Optics & Laser Technology 180 (2025) 111479

Available online 18 July 2024
0030-3992/© 2024 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-
nc-nd/4.0/).

Full length article

Femtosecond laser removal of antifouling paints on glass fibre reinforced
plastic used in maritime industry

Alicia Moreno-Madariaga a,*, Aurora Lasagabáster-Latorre b, María L. Sánchez Simón c,
Javier Lamas a, Alberto Ramil a, Ana J. López a

a Campus Industrial de Ferrol, Laboratorio de Aplicaciones Industriales del Láser, CITENI, Universidade de Coruña, Spain
b Dpto Química Orgánica I, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Spain
c Campus Industrial de Ferrol, Escuela Politécnica de Ingeniería de Ferrol, Universidade da Coruña, Spain

A R T I C L E I N F O

Keywords:
Femtosecond laser
Laser cleaning
Antifouling paint
GFRP
Maritime environment

A B S T R A C T

In this work we investigated the use of ultrashort laser pulses to clean antifouling paint from samples of glass
fibre reinforced polymer (GFRP), a composite material widely used in shipbuilding. Samples were prepared with
two types of paint, self-polishing and hard matrix, according to the scheme used in the shipyard. The paints and
the GFRP substrate were characterised by Fourier transform infrared (FTIR) spectroscopy and scanning electron
microscopy (SEM) with energy dispersive X-ray spectrometry (EDS). The effectiveness of the cleaning treatment
and the effects on the substrate were evaluated by optical microscopy, interferometric microscopy, SEM-EDS and
FTIR spectroscopy. The results indicate that satisfactory cleaning was achieved with controlled removal of un-
wanted layers without damaging or chemically altering the polymer bulk. The surfaces were also evaluated by
SEM and interferometric microscopy to characterise morphological changes, and their wettability was charac-
terised by contact angle measurements. In addition, the results were compared with those obtained by the
conventional mechanical method (paint scraping and sanding). A roughening of the laser cleaned surfaces was
observed compared to untreated surfaces as well as compared to mechanically cleaned surfaces. Laser treatment
caused a decrease in wettability; sanded surfaces showed comparable behaviour. This study demonstrates the
potential of femtosecond lasers for safe and effective cleaning of GFRP substrates in a more environmentally
friendly manner.

1. Introduction

Composite materials are extensively used in maritime applications
due to their corrosion resistance, lightweight, and ability to manufacture
complex shapes without expensive tooling, making them advantageous.
Glass fibre reinforced plastics (GFRP) are widely used for the hulls of
pleasure boats, military crafts, fishing boats, and catamarans. They are
also used in Marine Renewable Energy Production for elements such as
turbine blades and propellers [1].

Biofouling is a significant issue for the maritime industry, involving
the attachment of marine flora and fauna to submerged structures [2].
When marine organisms attach to the hull of ships or naval vessels, they
can increase frictional resistance, reducing speed and manoeuvrability,
increasing fuel consumption and corrosion damage, and posing a bio-
security risk. In addition, hull fouling can increase the frequency of dry-
docking, resulting in significant economic losses [3,4]. Therefore, it is

important to prevent such attachments [5,6].
One of the most commonly used preventive methods nowadays is the

application of antifouling paints that contain biocides. These biocides
act as repellents or poisons for potential settling organisms. In the EU,
antifouling products are regulated under the Biocidal Products Regula-
tion (BPR), which stipulates that the recommended dose should be the
minimum necessary to achieve the desired effect. Therefore, periodic
cleaning and repainting of the surface are necessary to maintain anti-
fouling performance. Currently, antifouling paints are typically removed
using mechanical methods such as hydroblasting, sandblasting,
scraping, or sandpapering. However, these methods generate paint
waste and/or wastewater that is highly contaminated with metals and
other biocides; and even biological risks when in-water cleaning systems
remove hull fouling [7–10]. So that, it is important to find alternative
methods that are more environmentally friendly [11–14].

In this context, the laser cleaning technique is presented as a highly

* Corresponding author.
E-mail address: alicia.moreno@udc.es (A. Moreno-Madariaga).

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Optics and Laser Technology

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https://doi.org/10.1016/j.optlastec.2024.111479
Received 10 April 2024; Received in revised form 18 June 2024; Accepted 13 July 2024

mailto:alicia.moreno@udc.es
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Optics and Laser Technology 180 (2025) 111479

2

effective alternative for removing various types of paints and coatings.
Laser cleaning has been applied in various industrial fields, including
aerospace and automotive [15–19], and even for the removal of radio-
active contaminants [20]. It has also been used in fields such as dentistry
[21] and heritage conservation [22–25]. Compared to conventional
cleaning methods, laser cleaning offers several advantages. It is a se-
lective, non-contact, and environmentally friendly technique [26].
When combined with industrial robots, laser technology can accurately
clean contaminants in large and complex structures, which greatly im-
proves quality and efficiency [27–32].

Short pulse lasers with pulse durations in the nanosecond or micro-
second range are commonly used for cleaning, and research on paint
removal has mainly focused on metal matrices [33–38], with relatively
little research reported on fiber reinforced composites [39–41]. The
main challenge in laser processing of composites is the suppression of
thermal damage to the bulk resin or load-bearing fibres [42], because of
the the difference in thermophysical properties of fibres and matrices
[43]. In this sense, studies on the effects of nanosecond lasers with
wavelengh in the IR and UV rarge on fibre reinforced plastics showed
that in both regimes the thermal effect of the laser is the dominant
cleaning mechanism in paint stripping; even in the UV range where
photochemical mechanisms are involved in addition with thermal stress
[44–46]. On the other hand, with ultra-short pulsed lasers (picosecond
or femtosecond range), the interaction between the laser and the ma-
terial is based on electrostatic processes and the pulse duration is shorter
than the time required for heat to diffuse through the material [47]. As a
result, there is minimal heat transfer into the bulk of the material and
they are therefore increasingly used, particularly for processing heat-
sensitive materials such as cultural heritage objects [48–52] or com-
posites [53–56]. Focusing on laser processing of GFRP composites, many
scholars have studied GFRP laser cutting and drilling and found that
thermal damage is reduced by minimisation of irradiation time,
furthermore using ultrashort pulses, the pulse duration and wavelength
had a great impact on the heat-affected zone (see Bhaskar et al. [57] and
references therein); however, to the best of our knowledge, few litera-
tures have reported paint removal on GFRP, and in such cases IR lasers
have been used. [58].

So that, although studies on UV laser surface treatment of composites
have shown promising results [59,60], their use in automation processes
or integration with robots is limited because UV lasers cannot be guided
by conventional silica based optical fibre [61]. Infrared lasers, on the
other hand, can be guided through an optical fibre and are therefore
very suitable for automation [35,62,63]. This aspect is of great impor-
tance when considering the applicability of this study in industrial fields,
given the size and shape of the surfaces to be cleaned, ship hulls and
other elements with very different sizes and shapes, which can, how-
ever, be tackled thanks to the technological advances in high power
ultrafast fiber laser systems [41,64,65].

In the context of maritime applications, there is limited literature on
laser cleaning of paints or coatings, and where such references exist,
they typically involve the use of nanosecond lasers [66–72]. Further-
more, due to the fact that functional paints or coatings are made up of a
combination of different pigments, resins and other additives designed
to improve specific properties, the response of different types of paint to
laser irradiation can be a challenge [24,48,73,74].

This work investigates the use of ultrashort pulse laser cleaning
technology for removing antifouling paints from GFRP surfaces used in
shipbuilding. The study focuses on two commonly used antifouling
coatings: self-polishing and hard matrix. Prior to laser cleaning, the
paints and GFRP surface were characterized, and the efficiency of the
laser ablation process was evaluated. The paint removal efficiency and
effects on the substrate, including its chemical composition, surface
roughness, and wettability, were used to characterize the results. These
factors could potentially impact the repainting procedure. Additionally,
the study compared the results of decoating laser with those of the
conventional mechanical method.

2. Materials and methods

2.1. Samples preparation

The composite samples utilised in this study were prepared in the
shipyard using the manual laminating method, which consists of adding
successive layers of resin and fibre in a mould. The process of con-
structing a hull laminate begins with a mould that has been impregnated
with release agents (wax). Fibreglass mats, which have been impreg-
nated with polyester resin, are then applied layer by layer and welded
together once the resin has cured. To create the external surface of the
hull, a layer of gel-coat was applied before layering the part [75,76]. The
resin used, identified as POLYCOR ISO NPG PA and manufactured by
Polynt Composites, is a white isophthalic neopentylglycol chosen for its
high resistance to water and blistering. After demoulding, the gel-coat
surface was sanded to remove all traces of release agent and achieve
good mechanical anchorage for the painting scheme. A white primer
coat was applied to improve mechanical adhesion for the antifouling
paint application. Additionally, the primer provides protection, espe-
cially for boats laminated with polyester. Finally, two coats of anti-
fouling paint were applied. All coats were applied using a roller.

Two types of Hempel antifouling coatings were used in this study: a
red self-polishing coating, referred to as ’red-SP’, and a hard or insoluble
matrix antifouling white paint, identified as ’white-HM’. After the
painting process was completed, the glass fibre reinforced plastic
(GFRP) laminate, which was approximately 8 mm thick, was cut into flat
sheets measuring (100 × 100) mm2.

To be used as a reference, unpainted gel-coat samples were also
available. Prior to applying analytical techniques, the gel-coat surfaces
were cleaned with detergent-based cleaners and a special solvent to
remove all traces of the release agent.

To compare the effects of laser treatments with those of the con-
ventional mechanical method, we reproduced the manual process in the
laboratory. We used a paint scraper to clean the gel-coat surfaces and
then abraded them with 120 grit sandpaper using an orbital sander to
obtain a good mechanical grip for the application of the new paint.
Finally, we rinsed the prepared surfaces with fresh water to remove dust
and sandpaper residue.

2.2. Femtosecond laser system

The samples were subjected to laser irradiation to completely
remove the antifouling paint while minimizing damage to the gel-coat
surface. The laser used was the Spirit system from Spectra Physics,
emitting at a wavelength of 1040 nm and with a pulse width of less than
400 fs. The laser output had a near-Gaussian intensity profile (M2 < 1.2)
and a beam diameter of 1.5 mm at the laser head exit. The laser beam has
a horizontal polarisation (>100:1). The pulse rate can be adjusted from a
single shot up to 1 MHz, with a maximum pulse energy of 40 μJ at 100
kHz. The maximum average output power exceeds 4W. To scan the laser
beam in the X-Y direction, a two-mirror galvanometric scanner (Raylase
SuperscanIII-15) was utilised. The beam was focused to a diameter of 30
μm using an F-theta objective lens with a focal length of 160 mm. At the
working plane, the beam polarisation is parallel to the Y direction.

The samples undergo processing in ambient air, and the laboratory’s
extraction system is utilized to eliminate gases and particles produced
during ablation. A scheme of the experimental setup used is shown in
Fig. 1.

2.3. Analytical techniques

The surfaces were characterized before and after laser processing
using various techniques:

2.3.1. Optical microscopy
To assess the continuity of the coating layers and measure their

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Optics and Laser Technology 180 (2025) 111479

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thickness, as well as to obtain a first qualitative assessment of the laser’s
effectiveness in removing paint, we used a Nikon Eclipse L150 on pol-
ished cross-sections of fresh samples.

2.3.2. Scanning electron microscopy (SEM)
The study employed a JEOL JSM-7200F scanning electron micro-

scope (SEM) with energy dispersive X-ray spectrometry (EDS) capabil-
ities in both secondary electrons (SE) and back-scattered electrons (BSE)
modes. The samples were carbon-coated using a Cressintong 208HR
turbo molecular pump. Optimal observation conditions were achieved
with an accelerating voltage of 15 kV and a working distance of 9–10
mm. Analyses were conducted on both the surface and cross-section of
the samples.

2.3.3. Fourier transform infrared spectroscopy FTIR
The Fourier Transformed Infrared (FTIR) data were performed on a

Jasco 4700 spectrometer coupled with an IRT-7100 Microscope equip-
ped with an MCT detector. The spectra were conducted in the Attenu-
ated ReflectanceMode (ATR) by using the ATR-5000-SS Clear-View ATR
objective with a ZnS prism. At least three individual spectra were
collected for each sample area between 3600 and 650 cm− 1. Each
spectrum was compiled from 64 scans with a resolution of 4.0 cm− 1. The
original paints, the gel-coat and a completely cleaned area were also
examined in the conventional ATR spectrometer between 3800 and 550
cm− 1. All the spectra were analysed using the Bruker OPUS® software
version 5.5. They were subjected to baseline, ATR correction and nor-
malised with respect to the C–H stretching bands (3000–2710 cm− 1).

Fig. 1. Scheme of the experimental setup.

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This group of bands has been selected owing to the fact that they are the
least affected by the laser cleaning treatment.

2.3.4. Interferometric microscopy
The surface texture was characterized using a Zygo NewView 600

profilometer with a 20x objective (field of view 349 μm × 262 μm,
resolution 640× 480 pixels, Z-scan resolution 0.1 nm). Scientific Python
was used for data processing, analysis, and visualization. Areal rough-
ness parameters were used to characterize the surface roughness before
and after paint removal, following standard UNE-EN ISO [77].

2.3.5. Contact angle measurement
To assess surface wettability, we measured the static contact angle

using a Krüss Drop Shape Analyzer-DSA25 with an automatic dosage
system and a Guppy PRO F-032B CCD camera. We followed the sessile
drop method outlined in Standard UNE-EN [78] and measured the static
contact angles of four 4 µL deionized water droplets.

3. Results and discussion

3.1. Samples characterization

Fig. 2 displays optical microscope images of the cross sections of the
samples, revealing the distinct layers of the laminate coating system.
The thicker GFRP layer is located at the bottom. It is evident that the
paint layer’s continuity is comparable in both cases, red-SP and white-
HM, but with varying thicknesses. The mean value for the red paint is
(78.9 ± 8.7) µm, while for the white paint, it is (100.0 ± 9.0) µm. The
thickness of the intermediate primer is (29.6 ± 2.5) µm in both cases.
The gel-coat layer has a thickness of (193.7 ± 15.7) µm for the red-SP
sample and (128.1 ± 7.5) µm for the white-HM one.

The composition determination of both the gel-coat and the

antifouling paint was carried out by ATR-FTIR and SEM-EDS. Fig. 3
shows the normalised ATR-FTIR spectra of the gel-coat and the original
red and white paints. The band assignments are described in detail in
Table 1. In coherence with the composition of POLYCOR ISO NPG PA,
the spectral bands of the gel-coat correspond to an aromatic polyester
resin, specifically indicated by the presence of the carbonyl (C=O) and
asymmetric C-O-C stretching bands of the ester groups at 1723 and
1230 cm− 1, respectively. The presence of the isophthalic moiety is

Fig. 2. Optical microscopy images (10x) of cross sections of the red-SP (a) and white-HM (b) samples. (For interpretation of the references to color in this figure
legend, the reader is referred to the web version of this article.)

Fig. 3. Normalised ATR-FTIR spectra of the gel-coat and the red and white
paints. (For interpretation of the references to color in this figure legend, the
reader is referred to the web version of this article.)

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confirmed by the small bands at 3074 and 1610 cm− 1 ascribed to C–H
and C=C stretching in aromatic rings, respectively [79]. Adsorbed water
is revealed by the absorption bands associated with the O–H stretching
and bending vibrations at 3600–3000 cm− 1 and 1646 cm− 1,
respectively.

An FTIR analysis between 4000 and 600 cm− 1 does not unambigu-
ously detect most inorganic elements. The presence of Ti (11.8 %), Si
(3.5 %), Mg (1.7 %) and Al (0.5 %) is revealed by SEM-EDS elemental
analyses. With this fact in mind the medium-intensity band at 727 cm− 1

may be ascribed to the Ti-O stretching of TiO2; this oxide is added as a
white pigment for providing maximum whiteness and opacity, besides
UV protection [80]. Furthermore, although SEM elemental analysis
detects Si, the relatively low intensity of the band at 1027 cm− 1 (nor-
mally a very strong band attributed to O-Si-O stretching vibrations)
[81], may be due to the limitations of the ATR mode in heterogeneous
samples, due to the shallow depth of penetration of the radiation;
therefore, the analysis is limited to the upper few microns of the surface.
The presence of Si may be due to silicate particles (SiO2) frequently
included to enhance the coating’s mechanical properties [81]. At any
rate, these instances highlight the restrictions of FTIR and the need to
combine several techniques in any investigation of complex mixtures of
unknown materials.

Concerning the spectra of the red and white paints compared in
Fig. 3, they consist mostly of the binder plus bands assigned to metal
complexes, pigments used as biocides and other fillers (Table 1). FTIR
spectra reveal that the binders of both paints consist of blends or co-
polymers of acrylate esters and acrylic acid. Both paints exhibit strong
metal carboxylates bands (CO2

–) formed by the reaction of the carboxylic
acid groups of the binder with the metals present in the aforementioned
fillers, often metal oxides such as Cu2O, red colored biocide probably the
main additive in the red paint, and ZnO, frequently synergistically
combined with copper compounds [82,83]. Specifically, the strong

peaks in the region 1585–1540 cm− 1 and the bands in the range
1460–1390 cm− 1 are due to the asymmetric and symmetric stretching
vibrations of the aforementioned CO2

– groups, respectively [81]. These
carboxylate bands are more intense in the red paint than in the white
paint. Besides, the broad bands between 3600–3100 cm− 1, due to the
stretching of hydroxyl groups, is shifted to lower wavenumbers in the
red-SP compared to the white-HM, indicating stronger hydrogen-
bonding.

Further, the red paint spectrum exhibits stronger bands in the range
between 1094–1010 and 974 cm− 1 which can be assigned the stretching
of O-Si-O bonds of silicate (SiO2) [84]. Nevertheless, copper oxide
(Cu2O) also contributes to the 974 cm− 1 band intensity [85,86]. In
addition, the spectrum of the red paint exhibits a strong band centered at
604 cm− 1, which may be allotted to the Cu-bond in Cu2O, although this
band is shifted to lower wavenumbers compared to literature [87]. By
contrast, the main absorption of ZnO occurs below 600 cm− 1, which is
out of the detection range of the FTIR spectrometer [88]. Finally, the
biocide Copper(I) thiocyanate (CuSCN) is unambiguously identified in
spectrum of the white paint due to the band at 2155 cm− 1, ascribed to
the stretching vibration of the SCN- group [89]. This band is absent in
the red paint.

To complete the identification of the paint compositions, the SEM-
EDS elemental analyses of the red paint detected Cu (4.5 %), Zn (3.9
%), Si (0.8 %) and S (0.8 %). These results confirm the synergistic
combination of the biocides Cu2O and ZnO, being S a frequent impurity
present in ZnO. In relation with the white paint, the elemental analysis
revealed Cu (3.8 %), S (2.2 %), Zn (12.1 %), Ti (9.9 %) and Si (1.1 %).
Further, the coincidence of the color mapping distributions of Cu and S
elements ratify the presence of Copper(I) thiocyanate as biocide; similar
to the red paint, ZnO is combined with a copper compound to syner-
gistically increase antifouling effects and TiO2 is added to provide
whiteness, opacity and UV protection [80]. Finally, Si is present in both
the red and white paints, probably as SiO2, to improve mechanical
properties and/or to the silanes used in the primer coat [81]. SEM mi-
crographs (BSE) at different magnifications together with composition
maps of the red and white paints are available in supplementary mate-
rial (Fig. S1).

3.2. Laser paint removal

3.2.1. Efficiency of paint removal
Laser ablation tests were conducted on a (10 × 10) mm2 surface

using parallel sweeps separated by a distance that ensured a clean zone.
The tests were performed with the laser beam focused at the sample
surface at normal incidence. Decisions on the most appropriate values
for efficient paint removal (higher extraction) were made through a
series of exploratory experiments, taking into paint removal were made
through a series of exploratory experiments, taking into account previ-
ous studies on the removal of spray paint using ultrashort pulse lasers.
The parameters involved in laser treatments, such as repetition fre-
quency, fluence, scan speed, and laser trajectories, were considered
[90].

The preliminary test results were evaluated through visual inspec-
tion using an optical microscope. The selected irradiation conditions for
this study were those that produced a clean surface with no significant
paint residue and no visible damage to the gel-coat. Therefore, the
values used were: average powerP = 4 W; repetition frequencyf = 50
kHz; working distancewd = 0; scan speedv = 750 mm•s− 1; and line-to-
line displacement of 15 μm. The applied fluence was 10 J•cm− 2. With
these parameters, successive horizontal and vertical scans were per-
formed until the treated area was free of paint.

Fig. 4 displays optical microscope images of the laser-treated areas as
the number of laser passes increases. For the red-SP sample (Fig. 4a), the
degree of paint removal is low after 2 passes, and a darkening of the
remaining paint is visible. After 5 passes, the paint is entirely removed,
and the intermediate primer layer (dark grey) becomes visible. At 6

Table 1
Assignment of the infrared absorption bands of the normalised spectra of the
original materials.

Wavenumber (cm− 1) Group vibration Origin

3600–3100 OH stretching Water molecules
3074 aryl CH stretching Aromatic rings, Gel-coat
2954 CH3 asym. stretching Polyester and

polyacrylic resin
2926 CH2 asym. stretching Polyester and

polyacrylic resin
2854 CH3 CH2 sym. stretching Polyester resin, Gel-coat
2155 SCN stretching Copper(I) thiocyanate

biocide
1723 C=O stretching Polyester and

polyacrylic resin
1646 OH bending Water molecules
1610 C=C aromatic stretching Aromatic rings, Gel-coat
1583/1542*, 1578/

1536**
Metal carboxylate COO–
asym. stretching

Metal complex,
polyacrylic resin

1457 C–H scissoring of CH2 Polyester and
polyacrylic resin

1405*, 1397** Metal carboxylate COO-sym.
stretching

Metal complex,
polyacrylic resin

1230 C-O-C asymmetric stretching Polyester and
polyacrylic resin

1230 Si-CH3 bending Silanes, imprinting layer
1145 C-O-C symmetric stretching Polyester and

polyacrylic resin
1015 Si-O-Si stretching SiO2, silanes
973 Si-O-C, Cu–O SiO2, Cu2O
821 Si(CH3)2 rocking Silanes, imprinting layer
804 Skeletal vibrations Polyester and

polyacrylic resin
727 Ti-O stretching Gel-coat
676 Pigment
604** Cu–O bond Cu2O Biocide pigment
red ** and white* paint

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6

passes, most of the substrate is clean (lighter areas). Finally, after 7
passes, the surface achieves a satisfactory level of cleanliness. At this
microscope magnification, no traces of coating, paint or primer can be
detected. The images of the white-HM sample (Fig. 4b) indicate a slower
transition between the different layers. Therefore, after 3 passes, the
degree of paint removal is low and the darkening of the antifouling paint
is visible. After 6 passes, the substrate is still partially coated with
antifouling paint, while most of it is covered by the primer film. By the
7th pass, the paint is almost completely removed, and the substrate is
almost entirely covered by the primer film. After 9 passes, the paint is
satisfactorily removed. It is important to note that achieving a total and
uniform cleaning of the red and white painted surfaces required 7 and 9
passes, respectively. This was due to the non-uniformity of the layers.

To measure the ablation rate of both antifouling paints, we analysed
the laser-generated cavities using microscope interferometry and
measured their depth as the number of laser passes increased. Fig. 5
displays the topographic reconstruction of the well-defined structures in
the red-SP (Fig. 5a) and white-HM (Fig. 5b) paints after 6 and 7 passes,
respectively, as well as the cavity depth as a function of the number of
laser passes for each sample (Fig. 5c). The data show that the ablation
depth increases in a nearly linear manner with the number of laser
passes. The slopes obtained from the linear fit indicate a lower ablation
rate (17.87 μm⋅pass− 1) for the hard matrix paint, white-HM, compared
to the self-polishing, red-SP (21.76 μm⋅pass− 1), which is expected due to
the good mechanical resistance of the hard matrix antifouling. Both
removal rate, expressed in mm3⋅min− 1, and removal efficiencies
expressed in mm3⋅(min⋅W)–1, were also calculated and the results are
shown in Table 2. The correlation coefficient R2 of the fitted model is
given in parentheses.

3.2.2. SEM-EDS and ATR analysis
SEM-EDS and FTIR-ATR were utilised to assess the effectiveness of

the laser in removing the antifouling paints and to analyse the chemical
composition of the gel-coat surface exposed after laser cleaning. The
analysis focused on areas without paint and those with paint residues
under the optical microscope. Specifically, for the red-SP sample, the
areas treated with 2, 4, and 5 laser passes were examined, while for the
white-HM sample, the areas treated with 3, 4, and 6 laser passes were
analysed. Fig. 6 displays SEM images collected using the backscattered
electron detector (BSE, 50x) alongside the composition maps for areas

treated with 4 passes for the red SP sample (Fig. 6a, b) and 6 passes for
the white-HM sample (Fig. 6d, e). The analysis focused on an area where
the different layers (traces of paint, primer and gel-coat) were visible.

It can be seen from the micrographs that the composition of each
layer is clearly distinguishable thanks to their particular textures; so that
in the area with red antifouling paint (Fig. 6a), the markers are the high
contrast grains composed of Cu (CuO2) and Zn (ZnO). EDS elemental
analysis indicated the presence of Cu (11.4 %), Zn (10.3 %), Si (1.7 %)
and S (1.3 %) in this zone, as shown in the corresponding composition
map (Fig. 6b). In the white antifouling zone (Fig. 6d), the markers are
the high-contrast coarser grains composed of Cu and S (CuSCN), as well
as the finer and evenly distributed particles of Zn (ZnO) and Ti (TiO2),
both with strong contrasts. EDS elemental analysis revealed the presence
of Cu (4.4 %), S (2.5 %), Zn (9.2 %), Ti (9.0 %) and Si (1.3 %) (Fig. 6e).
The results of the SEM-EDS analyses showed that the composition of the
primer and gel-coat layers is the same for the red-SP and white-HM
samples; therefore, they are described together (EDS spectra data
correspond to the red-SP sample). With respect to the primer layer
(Fig. 6a, d), the marker is Si in the form of large particles of intermediate
contrast on the surface and Ti is also present in the form of small par-
ticles of high contrast. The spectrum collected in this area indicates that
the primer contains Si (7.0 %), Ti (4.9 %) and Mg (3.5 %) as major el-
ements and Fe (0.6 %) and Al (0.5 %) in smaller amounts (Fig. 6b, e).
The presence of Si may be due to the silane coupling agents used to
improve the adhesion on the substrate (gel-coat) [91]. Finally, the gel-
coat zone (Fig. 6a, d) is distinguished by its dark contrast; the pres-
ence of high-contrast Ti particles is also observed in this layer. EDS
analysis revealed that the dark contrast zone is due to C enrichment; in
addition, Ti (9.2 %), Si (3.5 %), Mg (1.6 %) and Al (0.4 %) were detected
(Fig. 6b, e).

By SEM-EDS, no traces of antifouling paints or primer were detected
on the revealed gel-coat surface after laser treatment. Indeed, the gel-
coat layer is easily identified by its low contrast in BSE mode and its C
and Ti content in the micrographs corresponding to the red-SP (Fig. 6c)
and white-HM (Fig. 6f) samples.

The spectra obtained by FTIR microscopy in the ATR mode for both
red and white paints and the corresponding treated surfaces upon
increasing laser passes are plotted in Fig. 7. The spectra of two different
areas after 4 and 6 passes in Fig. 7a and b, respectively, have been
included in order to show the heterogeneity of the surface at these stages

Fig. 4. Optical microscope images of the red-SP (a) and white-HM (b) samples after laser cleaning with increasing number of passes (indicated by the number in the
box). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

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of the cleaning process. The corresponding spectra are noted as 4.1, 4.2
passes and 6.1, 6.2 passes for the red-SP and white-HM samples,
respectively.

In relation with the red-SP sample (Fig. 7a), increasing the number of
laser passes leads to the progressive decrease of the bands assigned to
the metal carboxylate complexes at around 1585–1540 cm− 1 and 1390
cm− 1, asymmetric and symmetric stretching vibrations of the CO2

–

groups, respectively. These bands disappeared completely after 5 passes
and in the most part of the treated surface after 4 passes (Fig. 7a,
spectrum noted as 4.2). Additionally, the ATR conventional spectrum of
a totally cleaned area (see Fig. S2 in supplementary data) showed the
complete disappearance of the strong band at 604 cm− 1 allotted to the

Cu–O bond. These spectral alterations agree with the SEM-EDS
elemental analyses which demonstrate the absence of Zn and Cu ele-
ments and therefore, the complete paint removal in the areas identified
as primer and gel-coat. Concerning the white-HM sample (Fig. 7b), the
most noticeable changes in the infrared spectra from the first laser
passes are the progressive reduction of the band assigned to the thio-
cyanate at 2155 cm− 1, along with the bands attributed to the metal
carboxylate complexes at around 1585–1540 cm− 1 and 1390 cm− 1

(υCOO
– asymmetric and symmetric, respectively) until their complete

disappearance in most spots after 6 passes (Fig. 7b, spectrum noted as
6.2 in contrast with spectrum 6.1, showing the SCN band indicative of
paint residues) and on the cleaned surface. As well as in the red-SP
sample, these spectral modifications support the results obtained by
SEM-elemental analysis in the areas identified as primer and gel-coat, in
which no Zn, Cu or S are detected, ratifying the efficiency of the cleaning
treatment.

The rest of the spectral changes observed are very similar in the red-
SP and white-HM samples, thus they are described together. Parallel to
the disappearances of the aforementioned bands, the progressive
appearance of new strong bands is detected. The most intense one is the
broad band spanning from 1063 to 840 cm− 1, centered at 1000 cm− 1

and with some shoulders in the lower frequency region. These features
reveal the presence of several asymmetric Si-O-Si stretching modes

Fig. 5. Topographic reconstruction of the cavities created on the red-painted (a) and white-painted (b) samples at 6 and 7 passes, respectively. (c) Cavity depth as a
function of the number of laser passes for each sample. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of
this article.)

Table 2
Depth per pass and R2 (in parentheses), material removal rate and ablation ef-
ficiency for each sample.

Sample Depth
[µm pass− 1]

Removal rate [mm3

min− 1]
Efficiency [mm3 (min W)-
1]

red-SP 21.76
(0.93)

7.12 1.78

white-
HM

17.87
(0.99)

5.84 1.46

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8

[92,93]. Further, the new peaks centered at 1230 and 821 cm− 1 can be
assigned to the bending and rocking vibrations of Si-CH3 and Si-(CH3)2
groups, respectively. Simultaneously, the increase of the broad band
between 3600–3000 cm− 1 (νOH) may be caused by the occurrence of –Si-
OH groups. These bands can be mainly ascribed to the silicate filler
(SiO2) and even to traces of the silanes in the primer [93]. Only in the
red-SP sample and in some areas after 4 or 5 passes, the band assigned to
the stretching of Ti-O bond at 727 cm− 1 (clearly detected in the original
gel-coat spectrum) reappears [80]. The changes just described, together

with the results of SEM-EDS analysis, can be explained by the progres-
sive exposure of the primer layer and gel-coat after paint removal.

Further, additional new bands are detected at around 1643 and 1506
cm− 1 from 4 and 6 passes for the red-SP and white-HM samples,
respectively. These bands are not present in the original gel-coat spec-
trum and their origin could be ascribed to the bending of OH groups
from water molecules hydrogen bonded to the Si-O-Si structure, and to
the appearance of negatively charged silane groups (− SiO-), respec-
tively [92]. Another possible origin of these bands is the increasing

Fig. 6. SEM micrographs (BSE, 50x) together with composition maps of the surface after laser cleaning with different number of passes. (a-c) red-SP sample and (d-f)
white-HM sample. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

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9

presence of aromatic moieties, which together with the decrease in the
carbonyl stretching band centered at 1723 cm− 1, may be due to the
chemical degradation of the polyester resin produced by laser radiation
[94,95]. The latter degradation reactions might explain the change in
coloration to a greyer and darker appearance of the gel-coat after the
laser treatment. Similar changes in coloration and increasing darkness
have been described by previous authors in laser cleaning of spray paints
[74,96]. Further, using optical microscopy and SEM of cross-sections of
the laser-treated samples (see Fig. S3 in supplementary data), it was
possible to estimate the thickness of the altered gel-coat layer to be
about 10 − 15 μm i.e. the laser alteration effects are confined to the
outermost layers of the gel-coat and do not affect the polymer bulk.

3.3. Surface morphology characterization

The morphology of the laser cleaned surfaces was observed by both
electron microscopy and interferometric microscopy.

SEM images in secondary electron mode of the surfaces before and
after laser cleaning are shown in Fig. 8. Areas with residues of paint were
also analyzed, the corresponding micrographs are provided in supple-
mentary material (Fig. S4). As can be seen, superimposed to the laser
generated crosshacht pattern, small bumps appear, not noticeable in BSE
mode, and the surfaces become rough after processing of both red-SP
(Fig. 8a, b) and white-HM (Fig. 8a, d) samples. It can be observed that
the femtosecond pulses generated a micrometer-scale (<10 µm) a
granulate or globularpattern on the surfaces (Fig. 8c, e).

Interferometric microscopy corroborates the SEM observations as
can be seen in Fig. 9 where topographies of the pristine gel-coat surface
(Fig. 9a) and the laser-treated surfaces (Fig. 9b, c) are shown. As can be
seen, the resulting surface is rougher after laser cleaning. As mentioned
previously, surface roughness could play a crucial role in the repainting
procedure, owing to the fact that suitable roughness favours the bonding
performance between coatings.

Roughness is typically characterised by the mean roughness Sa and
root mean square roughness Sq. However, these amplitude parameters
alone are insufficient to describe the complexity of the surface. There-
fore, this work includes parameters that evaluate the shape of the height
distribution, namely the skewness Ssk and the kurtosis Sku. In addition,
we have included the developed interfacial area ratio Sdr, which is a
significant parameter for surface wettability. Table 3 depicts the values
of these areal roughness parameters, measured before and after laser
treatment, in addition with those of the mechanically cleaned surface. It
can be seen that both Sa and Sq of the laser cleaned surface are about
twice the values of the untreated gel-coat. As for the parameters eval-
uating the shape of the height distribution, the skewness Ssk, is around

zero; which results congruent with the applied laser scanning scheme
(crosshatch) and the kurtosis Sku, around 3, indicating a more homo-
geneous height distribution and less pronounced surface peaks after
laser processing compared to the untreated gel-coat surface (reference
surface). With respect to the gel-coat after conventional mechanical
paint removing, Sa and Sq also increase, but unlike the laser treatment in
this case the distribution of heights is no longer symmetrical, with a
negative skewness Ssk and a kurtosis Sku above 3; which indicates the
presence of sharp peaks.

The developed interfacial area ratio, Sdr expressed as the percentage
of the definition area’s additional surface area contributed by the
texture as compared to the planar definition, experiments an important
increase with respect to the untreated gel-coat after laser paints removal,
so that Sdr = 0.10 ± 0.01 in the pristine gel-coat andSdr = 0.78 ± 0.00
andSdr = 0.68 ± 0.01 for removed red-SP and white-HM, respectively.
On the other hand, after mechanical cleaning, the resulting gel-coat
surfaces are more irregular (Fig. 9d, e) and with lower values of Sa
and Sq than the laser-treated ones, and consequently the developed area
Sdr is lower; resultingSdr = 0.38 for both red-SP and white-HM cleaned
samples.

3.4. Wettability evaluation

The behaviour of solid surfaces in a wide range of applications de-
pends on the wetting response; so that it is important to evaluate how
the surface modifications in the gel-coat layer after femtosecond laser
paint removal affects its wetting characteristics. The wettability is usu-
ally characterised in terms of the static contact angle, θ, that describes
the behaviour of a liquid droplet on a solid surface in air, and is defined
as the angle between the tangent at the three-phase point and the solid
surface. Solid surfaces with θ < 90◦ are considered hydrophilic, while
surfaces with θ ≥ 90◦ are considered hydrophobic. Fig. 10 shows the
contact angle values of the antifouling painted surfaces and the gel-coat,
obtained both for the pristine sample and for the samples cleaned by the
laser and mechanical methods; the contact angle values have been
calculated with 95 % confidence. As can be observed, the self-polishing
coating (red-SP) with θ = 92.8◦ ± 0.1◦ shows hydrophobic behaviour
(θ > 90◦ ) while the hard matrix one (white-HM) with θ = 78.3◦ ± 0.5◦

has hydrophilic character (θ < 90◦ ), in agreement with other reported
results [97].

With respect to the uncoated gel-coat surface (reference surface), the
contact angle is θ = 79.2◦ ± 0.2◦, corresponding to a hydrophilic char-
acter. After laser paint removal, the contact angle of the gel-coat in-
creases to θ = 112.7◦ ± 0.3◦ (red-SP) and θ = 112.2◦ ± 0.2◦ (white-HM),
so that the fs laser treated surface acquires a hydrophobic behaviour. In

Fig. 7. Normalised ATR-FTIR spectra of the red-SP (a) and white-HM (b) samples before cleaning and laser treated areas upon increasing laser passes. (For inter-
pretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

A. Moreno-Madariaga et al.



Optics and Laser Technology 180 (2025) 111479

10

the case of the abraded surfaces, the contact angle also increases,
although to slightly lower values than for the laser method, being θ =

111.1◦ ± 0.6◦ for the red SP andθ = 109.7◦ ± 0.4◦ for the white-HM. The
greater dispersion of these values compared to those obtained with the
laser method is due to the lower uniformity of the surface finish obtained
with the mechanical method, as mentioned above, which makes the
measurement more difficult.

Thus, despite the significant increase in gel-coat surface roughness
after the femtosecond laser process, the wettability of the surface

decreases; the same is observed when applying the conventional me-
chanical technique.

The wettability of a surface depends on its chemical composition and
morphology. The changes in chemical composition observed by FTIR
indicate a partial degradation of the gel-coat polyester resin with an
increase in aromatic moieties, which could enhance hydrophobicity
[94]. Although to a lesser extent than changes in surface roughness,
these chemical modifications could contribute to the transition from a
hydrophilic to a hydrophobic surface. Due to the greater importance of

Fig. 8. SEM micrographs (SE) at different magnifications of surfaces before and after laser cleaning. (a) untreated gel-coat; (b, c) red-SP sample and (d, e) white-
HM sample.

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11

roughness, the study focuses on this property in the following
paragraphs.

To explain the effect of surface roughness induced by the femto-
second laser on wettability, we must consider the Sdr parameter. This
parameter is the roughness parameter that best approximates the in-
crease in solid surface area in both the Wenzel and Cassie-Baxter
wettability models [98]. The Wenzel theory implies that a hydrophilic
surface (θ0 < 90◦ ) will become more hydrophilic as the surface rough-
ness increases. The Wenzel contact angle (θW) varies according to the
equation, equation (Eq. (1))

cosθW = rcosθ0 (1)

where the roughness ratio r is defined as the ratio of the actual surface
area wetted by the liquid and the projected planar area (r = 1 + Sdr).
Wenzel equation is based on the hypothesis that liquid enters irregu-
larities present on the surface, leading to a homogeneous wetting regime
with an increased contact area [99]. In the wetting regime given by the
Cassie-Baxter model (Eq. (2)), it is energetically favourable for the liquid
to form a droplet that rests on the edges of the surface while air fills the
space between solid and liquid, forming air pockets [99]. Consequently,

Fig. 9. Reconstruction of the surface topography of the samples before and after laser and mechanical cleaning: (a) untreated gel-coat; (b, c) laser cleaned red-SP and
white-HM samples and (d, e) mechanically cleaned red-SP and white-HM samples. (For interpretation of the references to color in this figure legend, the reader is
referred to the web version of this article.)

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12

only a small fraction of the solid surface is in contact with the liquid. The
Cassie-Baxter contact angle θCB can be calculated as:

cosθCB = − 1+ f + rf fcosθ0

or

cosθCB = rfcosθ0 − fG
(
rfcosθ0 +1

)
(2)

where f is the fraction of the projected area of the solid surface under the
drop that is wetted by the liquid (solid–liquid fraction), fG is the liq-
uid–air fraction (f +fG= 1) and rf is the roughness ratio of the wetted
area. When f = 1, rf = r and the Cassie-Baxter equation is equivalent to
the Wenzel equation. It is important to note that both equations are
correct only if the drop is sufficiently large in relation to the typical
roughness scale [100].

In this theoretical framework, the Cassie-Baxter model would explain
the behaviour of the gel- coat surface observed after the application of
laser and mechanical cleaning methods. By increasing the liquid–air
fraction fG, an initially hydrophilic surface can become hydrophobic
[101]. For this change in surface behaviour to take place,fG must have a
minimum value and, in addition, it must be higher the rougher the
surface is (increase of rf ) [102].

In previous work on femtosecond laser texturing [103,104] we have
found that the morphology and scale of roughness are influenced by a
variety of parameters, of which material properties and laser parameters
are themost important. Thus, for a givenmaterial, it might be possible to
modify its surface morphology to tailor its wettability by selecting the
appropriate laser processing parameters. However, in this work we have
focused on analysing the feasibility of the fs laser for the removal of
antifouling paints on a polymeric material, choosing the process pa-
rameters according to complete paint removal and minimal thermal
damage to the substrate gel-coat. Based on the results obtained, further
analysis of the irradiation parameters would be required to explore the
possibility of selectively roughening the gel-coat substrate to increase its
wettability.

4. Conclusions

In this paper we present what we consider to be, to the best of our
knowledge, a novel femtosecond laser cleaning method for the removal
of surface coatings of antifouling paints on GFRP laminates used in
maritime applications. The paints used in this study correspond to the
most common types in this field, referred to as hard matrix and self-
polishing antifouling paints, respectively. Prior to laser cleaning, the
paints and the GFRP surface were characterised and the efficiency of the
laser ablation process was evaluated in terms of paint removal and ef-
fects on the polymer substrate. The results were compared with those
obtained by the conventional mechanical method. The main conclusions
of this study are as follows:

• Characterisation of the different layers of the samples, i.e. gel-coat,
primer and antifouling paints was first carried by FTIR and SEM-
EDS. The gel-coat consists of an aromatic polyester resin, plus a
relatively high content of TiO2 and SiO2 added as fillers. Both anti-
fouling paints comprise a similar acrylic binder plus biocides and
other inorganic fillers. Especifically, the synergistic combination of
the biocides Cu2O and ZnO was proved in the red-SP, whereas
Copper(I) thiocyanate and ZnO have been detected in the white-HM.
The hard matrix paint further contains a relatively high amount of
TiO2. Lastly, Si (around 1%) was identified in both antifouling paints
and assigned to SiO2 and/or to the silanes used in the primer coat.

• The femtosecond pulsed laser can effectively clean the multi-layer
coating on the top surface of the GFRP with minimal thermal ef-
fects on the GFRP substrate by selecting the appropriate process
parameters. Complementary analyses by optical microscopy, SEM-
EDS and FTIR performed after successive passes of the laser,
allowed us to evaluate the effectiveness of the treatment. The

Table 3
Sa (arithmetic mean value), Sq (root mean square roughness), Ssk (skewness), Sku

(kurtosis) and Sdr (developed interfacial area ratio) for untreated and cleaned
samples.

Sa[µm] Sq[µm] Ssk Sku Sdr

UNTREATED SURFACES
red-SP 0.70 ±

0.18
0.87 ±

0.22
0.19 ± 0.32 3.48 ±

0.62
0.08 ±

0.01
white-

HM
0.91 ±

0.15
1.15 ±

0.22
0.28 ± 0.30 3.37 ±

0.34
0.13 ±

0.03
gel-coat 1.01 ±

0.15
1.31 ±

0.20
− 0.12 ±

0.27
3.85 ±

0.58
0.10 ±

0.01

LASER CLEANING
red-SP 2.05 ±

0.30
2.55 ±

0.38
0.01 ± 0.19 2.91 ±

0.01
0.78 ±

0.00
white-

HM
1.92 ±

0.25
2.38 ±

0.29
− 0.09 ±

0.01
2.88 ±

0.15
0.68 ±

0.01

MECHANICAL CLEANING
red-SP 1.51 ±

0.10
1.82 ±

0.13
− 0.41 ±

0.08
3.59 ±

0.17
0.38 ±

0.02
white-

HM
1.37 ±

0.09
1.74 ±

0.09
− 0.50 ±

0.11
3.62 ±

0.48
0.38 ±

0.01

Fig. 10. Contact angle θ [◦] for untreated and cleaned samples (reference surface contact angle has been repeated for easy reading).

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Optics and Laser Technology 180 (2025) 111479

13

complete paint removal was achieved after 7 passes and 9 passes on
the red-SP and white-HM samples, respectively.

• The ablation rate values obtained for both coatings demonstrate the
feasibility of the fs laser to remove, layer by layer, a typical coating
thickness of about 100 μm. In this sense, an ablation rate of 17.87
μm⋅pass− 1 was obtained for the hard matrix antifouling paint and
21.76 μm⋅pass− 1 for the self-polishing paint.

• Chemical changes have been detected in the gel-coat after laser
treatment. The darkening of the gel-coat is parallel to the variation in
the elemental composition (enrichment in C, decrease in TiO2) and
the appearance of new bands in the FTIR spectrum (assigned to ar-
omatic groups due to partial degradation of the polyester resin).
Nevertheless, the alteration effects are limited to the outermost
layers of the gel-coat (10–15 μm) and do not affect the mass of the
polymer bulk.

• The morphology of the gel-coat surface after laser cleaning changes
and becomes rougher, with mean roughness values almost double
those of the uncoated gel-coat and also higher than those obtained by
the conventional mechanical method. In addition, the surface texture
produced by the fs laser has a regular pattern, with a more homo-
geneous height distribution and less pronounced surface peaks than
the mechanically treated surface. In addition, the fs laser gives a
significant increase in the developed area Sdr.

• The untreated gel-coat surface has a hydrophilic character with a
contact angle of 79.2◦. The laser treatment results in an increase in
the initial contact angle to a value of approximately 112◦; which
corresponds to the Casie-Baxter wettability model. Similar results
were obtained for the mechanically cleaned surfaces.

In conclusion, this work demonstrates the validity and efficiency of
the femtosecond laser cleaning method for paint removal on GFRP with
minimal thermal damage to the substrate. Furthermore, given that the
surface roughness can be controlled by tuning the laser parameters,
further work is required to optimise the irradiation parameters to
remove the paint and produce a texture that increases the wettability of
the surface.

CRediT authorship contribution statement

Alicia Moreno-Madariaga: Writing – original draft, Methodology,
Investigation, Formal analysis, Data curation, Conceptualization.
Aurora Lasagabáster-Latorre: Writing – original draft, Resources,
Investigation, Formal analysis. María L. Sánchez Simón: Resources,
Investigation. Javier Lamas: Resources, Investigation, Formal analysis,
Conceptualization. Alberto Ramil: Supervision, Software, Methodol-
ogy, Investigation, Formal analysis, Conceptualization. Ana J. López:
Writing – review & editing, Supervision, Project administration, Meth-
odology, Funding acquisition, Formal analysis, Conceptualization.

Declaration of competing interest

The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to influence
the work reported in this paper.

Data availability

Data will be made available on request.

Funding and Acknowledgements

This research was partially supported by Grant PID2021-123948OB-
I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A
way of making Europe”, by the “European Union”.

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.
org/10.1016/j.optlastec.2024.111479.

References

[1] F. Rubino, A. Nisticò, F. Tucci, P. Carlone, Marine Application of Fiber Reinforced
Composites: A Review, Journal of Marine Science and Engineering 8 (1) (2020)
26, https://doi.org/10.3390/jmse8010026.

[2] C. Scianni, E. Georgiades, Vessel In-Water Cleaning or Treatment: Identification
of Environmental Risks and Science Needs for Evidence-Based Decision Making,
Front. Mar. Sci. 6 (2019) 467, https://doi.org/10.3389/fmars.2019.00467.

[3] A. Carchen, M. Atlar, Four KPIs for the assessment of biofouling effect on ship
performance, Ocean Eng. 217 (2020) 107971, https://doi.org/10.1016/j.
oceaneng.2020.107971.

[4] M.P. Schultz, J.A. Bendick, E.R. Holm, W.M. Hertel, Economic impact of
biofouling on a naval surface ship, Biofouling 27 (1) (2011) 87–98, https://doi.
org/10.1080/08927014.2010.542809.

[5] R. Adland, P. Cariou, H. Jia, F.-C. Wolff, The energy efficiency effects of periodic
ship hull cleaning, J. Clean. Prod. 178 (2018) 1–13, https://doi.org/10.1016/j.
jclepro.2017.12.247.

[6] I. Davidson, C. Scianni, C. Hewitt, R. Everett, E. Holm, M. Tamburri, G. Ruiz,
Mini-review: Assessing the drivers of ship biofouling management – aligning
industry and biosecurity goals, Biofouling 32 (4) (2016) 411–428, https://doi.
org/10.1080/08927014.2016.1149572.

[7] B. Hyun, P.-G. Jang, M.-C. Jang, J.-H. Kang, J.-H. Kim, J.-S. Ki, D.H. Choi, O.
H. Yu, J.-Y. Seo, W.-J. Lee, K. Shin, Development of Biological Risk Assessment
Protocols for Evaluating the Risks of In-Water Cleaning of Hull-Fouling
Organisms, Journal of Marine Science and Engineering 12 (2) (2024) 234,
https://doi.org/10.3390/jmse12020234.

[8] Z.Y. Soon, J.-H. Jung, C. Yoon, J.-H. Kang, M. Kim, Characterization of hazards
and environmental risks of wastewater effluents from ship hull cleaning by
hydroblasting, J. Hazard. Mater. 403 (2021) 123708, https://doi.org/10.1016/j.
jhazmat.2020.123708.

[9] A. Turner, Marine pollution from antifouling paint particles, Mar. Pollut. Bull. 60
(2) (2010) 159–171, https://doi.org/10.1016/j.marpolbul.2009.12.004.

[10] A. Turner, Metal contamination of soils, sediments and dusts in the vicinity of
marine leisure boat maintenance facilities, J. Soil. Sediment. 13 (6) (2013)
1052–1056, https://doi.org/10.1007/s11368-013-0686-2.

[11] M. Carve, A. Scardino, J. Shimeta, Effects of surface texture and interrelated
properties on marine biofouling: a systematic review, Biofouling 35 (6) (2019)
597–617, https://doi.org/10.1080/08927014.2019.1636036.

[12] C.M. Magin, S.P. Cooper, A.B. Brennan, Non-toxic antifouling strategies, Mater.
Today 13 (4) (2010) 36–44, https://doi.org/10.1016/S1369-7021(10)70058-4.

[13] E.R. Silva, O. Ferreira, P.A. Ramalho, N.F. Azevedo, R. Bayón, A. Igartua, J.
C. Bordado, M.J. Calhorda, Eco-friendly non-biocide-release coatings for marine
biofouling prevention, Sci. Total Environ. 650 (2019) 2499–2511, https://doi.
org/10.1016/j.scitotenv.2018.10.010.

[14] J. Telegdi, L. Trif, L. Románszki, Smart anti-biofouling composite coatings for
naval applications, in: Smart Composite Coatings and Membranes: Transport,
Structural, Environmental and Energy Applications, Elsevier Inc., 2016,
pp. 123–155, https://doi.org/10.1016/B978-1-78242-283-9.00005-1.

[15] J. Liang, Z. Wang, J. Gao, K. Gao, Path planning algorithm for laser removal of
paint from aircraft skin, J. Coat. Technol. Res. 21 (2) (2024) 537–546, https://
doi.org/10.1007/s11998-023-00836-w.

[16] S. Marimuthu, H.K. Sezer, A.M. Kamara, Applications of Laser Cleaning Process in
High Value Manufacturing Industries, Developments in Surface Contamination
and Cleaning: Applications of Cleaning Techniques 11 (2019) 251–288, https://
doi.org/10.1016/B978-0-12-815577-6.00007-4.

[17] M.K.A.A. Razab, A. Mohamed Noor, M. Suhaimi Jaafar, N.H. Abdullah, F.
M. Suhaimi, M. Mohamed, N. Adam, A.N. Yusuf, N. a., A review of incorporating
Nd:YAG laser cleaning principal in automotive industry, J. Radiat. Res. Appl. Sci.
11 (4) (2018) 393–402, https://doi.org/10.1016/j.jrras.2018.08.002.

[18] G. Zhu, Z. Xu, Y. Jin, X. Chen, L. Yang, J. Xu, D. Shan, Y. Chen, B. Guo,
Mechanism and application of laser cleaning: A review, Opt. Lasers Eng. 157
(2022) 107130, https://doi.org/10.1016/j.optlaseng.2022.107130.

[19] Z. Zhou, W. Sun, J. Wu, H. Chen, F. Zhang, S. Wang, The Fundamental
Mechanisms of Laser Cleaning Technology and Its Typical Applications in
Industry, Processes 11 (5) (2023) 1445, https://doi.org/10.3390/pr11051445.

[20] A. Kumar, M. Prasad, R.B. Bhatt, P.G. Behere, M. Afzal, A. Kumar, J.P. Nilaya, D.
J. Biswas, Laser shock cleaning of radioactive particulates from glass surface, Opt.
Lasers Eng. 57 (2014) 114–120, https://doi.org/10.1016/J.
OPTLASENG.2014.01.013.

[21] M. Nevins, M. Nevins, A. Yamamoto, T. Yoshino, Y. Ono, C.-W. Wang, D. Kim, Use
of Er:YAG Laser to Decontaminate Infected Dental Implant Surface in Preparation
for Reestablishment of Bone-to-Implant Contact, Int J Periodontics Restorative
Dent 34 (4) (2014) 461–466, https://doi.org/10.11607/prd.2192.

[22] M.P. Fiorucci, A.J. López, A. Ramil, S. Pozo, T. Rivas, Optimization of graffiti
removal on natural stone by means of high repetition rate UV laser, Appl. Surf.
Sci. 278 (2013) 268–272, https://doi.org/10.1016/j.apsusc.2012.10.092.

[23] P. Pouli, M. Oujja, M. Castillejo, Practical issues in laser cleaning of stone and
painted artefacts: Optimisation procedures and side effects, Appl. Phys. A Mater.

A. Moreno-Madariaga et al.

https://doi.org/10.1016/j.optlastec.2024.111479
https://doi.org/10.1016/j.optlastec.2024.111479
https://doi.org/10.3390/jmse8010026
https://doi.org/10.3389/fmars.2019.00467
https://doi.org/10.1016/j.oceaneng.2020.107971
https://doi.org/10.1016/j.oceaneng.2020.107971
https://doi.org/10.1080/08927014.2010.542809
https://doi.org/10.1080/08927014.2010.542809
https://doi.org/10.1016/j.jclepro.2017.12.247
https://doi.org/10.1016/j.jclepro.2017.12.247
https://doi.org/10.1080/08927014.2016.1149572
https://doi.org/10.1080/08927014.2016.1149572
https://doi.org/10.3390/jmse12020234
https://doi.org/10.1016/j.jhazmat.2020.123708
https://doi.org/10.1016/j.jhazmat.2020.123708
https://doi.org/10.1016/j.marpolbul.2009.12.004
https://doi.org/10.1007/s11368-013-0686-2
https://doi.org/10.1080/08927014.2019.1636036
https://doi.org/10.1016/S1369-7021(10)70058-4
https://doi.org/10.1016/j.scitotenv.2018.10.010
https://doi.org/10.1016/j.scitotenv.2018.10.010
https://doi.org/10.1016/B978-1-78242-283-9.00005-1
https://doi.org/10.1007/s11998-023-00836-w
https://doi.org/10.1007/s11998-023-00836-w
https://doi.org/10.1016/B978-0-12-815577-6.00007-4
https://doi.org/10.1016/B978-0-12-815577-6.00007-4
https://doi.org/10.1016/j.jrras.2018.08.002
https://doi.org/10.1016/j.optlaseng.2022.107130
https://doi.org/10.3390/pr11051445
https://doi.org/10.1016/J.OPTLASENG.2014.01.013
https://doi.org/10.1016/J.OPTLASENG.2014.01.013
https://doi.org/10.11607/prd.2192
https://doi.org/10.1016/j.apsusc.2012.10.092


Optics and Laser Technology 180 (2025) 111479

14

Sci. Process. 106 (2) (2012) 447–464, https://doi.org/10.1007/s00339-011-
6696-2.

[24] T. Rivas, S. Pozo, M.P. Fiorucci, A.J. López, A. Ramil, Nd:YVO4 laser removal of
graffiti from granite. Influence of paint and rock properties on cleaning efficacy,
Appl. Surf. Sci. 263 (2012) 563–572, https://doi.org/10.1016/j.
apsusc.2012.09.110.

[25] S. Siano, J. Agresti, I. Cacciari, D. Ciofini, M. Mascalchi, I. Osticioli, A.
A. Mencaglia, Laser cleaning in conservation of stone, metal, and painted
artifacts: State of the art and new insights on the use of the Nd:YAG lasers, Appl.
Phys. A Mater. Sci. Process. 106 (2) (2012) 419–446, https://doi.org/10.1007/
S00339-011-6690-8/FIGURES/34.

[26] W.M. Steen, J. Mazumder, Laser Cleaning, in: Laser Material Processing, Springer,
London, 2010, pp. 417–440, https://doi.org/10.1007/978-1-84996-062-5_11.

[27] T. Kaster, J.-H. Rissom, L. Gorissen, P. Walderich, J.-N. Schneider, C. Hinke,
Approach toward the application of mobile robots in laser materials processing,
J. Laser Appl. 35 (4) (2023) 042015, https://doi.org/10.2351/7.0001127.

[28] H.C. Lee, N.E. Pacheco, L. Fichera, S. Russo, When the End Effector Is a Laser: A
Review of Robotics in Laser Surgery, Advanced Intelligent Systems 4 (10) (2022)
2200130, https://doi.org/10.1002/aisy.202200130.

[29] Z. Pan, D. Liu, S. Li, Z. Deng, J. Liu, T. Chen, Path planning and pose correction of
robot laser cleaning process for specific surfaces of parts, Int. J. Adv. Manuf.
Technol. 127 (1–2) (2023) 349–364, https://doi.org/10.1007/s00170-023-
11535-6.

[30] Rodríguez, A., López, A. J., Lamas, J., Moreno, A., & Ramil, A. (2021).
Development of a laser cleaning robot system for the processing of 3D surfaces. In
S. Negahdaripour, E. Stella, D. Ceglarek, & C. Möller (Eds.), Multimodal Sensing
and Artificial Intelligence: Technologies and Applications II (p. 28). SPIE.
10.1117/12.2592111.

[31] A. Rodríguez, A.J. López, J. Lamas, A. Moreno, A. Ramil, Robot-assisted laser
ablation for 3D surfaces. Application for paint removal with ultrashort pulse laser,
Opt. Lasers Eng. 160 (2023) 107284, https://doi.org/10.1016/j.
optlaseng.2022.107284.

[32] J. Shuo, R. Yuan, M. Qingzeng, G. Hailong, L. Wenlong, C. Wei, Off-line
programming of robot on laser cleaning for large complex components, J. Phys.
Conf. Ser. 1748 (2) (2021) 022027, https://doi.org/10.1088/1742-6596/1748/
2/022027.

[33] R. Delmdahl, J. Brune, R. Pätzel, Ultraviolet Laser Cleaning of Carbon Fiber
Composites, Powder Metall. Met. Ceram. 55 (1–2) (2016) 1–4, https://doi.org/
10.1007/s11106-016-9772-5.

[34] G. Greifzu, T. Kahl, M. Herrmann, W. Lippmann, A. Hurtado, Laser-based
decontamination of metal surfaces, Opt. Laser Technol. 117 (2019) 293–298,
https://doi.org/10.1016/J.OPTLASTEC.2019.04.037.

[35] S. Harder, H. Schmutzler, P. Hergoss, J. Freese, J. Holtmannspötter, B. Fiedler,
Effect of infrared laser surface treatment on the morphology and adhesive
properties of scarfed CFRP surfaces, Compos. A Appl. Sci. Manuf. 121 (2019)
299–307, https://doi.org/10.1016/j.compositesa.2019.02.025.

[36] H.A. Jasim, A.G. Demir, B. Previtali, Z.A. Taha, Process development and
monitoring in stripping of a highly transparent polymeric paint with ns-pulsed
fiber laser, Opt. Laser Technol. 93 (2017) 60–66, https://doi.org/10.1016/J.
OPTLASTEC.2017.01.031.

[37] T. Shan, F. Yin, S. Wang, Y. Qiao, P. Liu, Surface integrity control of laser cleaning
of an aluminum alloy surface paint layer, Appl. Opt. 59 (30) (2020) 9313,
https://doi.org/10.1364/AO.404030.

[38] Q. Sun, J. Zhou, X. Meng, P. Li, Mechanical properties and microstructure
characteristics of 2024–T351 aluminum alloy specimen subjected to paint
removal by laser cleaning, Vacuum 211 (2023) 111927, https://doi.org/
10.1016/j.vacuum.2023.111927.

[39] T.L. See, Z. Liu, S. Cheetham, S. Dilworth, L. Li, Laser abrading of carbon fibre
reinforced composite for improving paint adhesion, Appl. Phys. A 117 (3) (2014)
1045–1054, https://doi.org/10.1007/s00339-014-8527-8.

[40] Y. Song, S. Wang, Y. Pan, Z. Li, L. Yu, Current research status of laser cleaning of
carbon fiber reinforced polymers, Mater. Today Commun. 39 (2024) 109312,
https://doi.org/10.1016/j.mtcomm.2024.109312.

[41] Z. Wang, Y. Ma, B. Yuan, C. Wu, C. Li, S. Sun, Development of Laser Processing
Carbon-Fiber-Reinforced Plastic, Sensors 23 (7) (2023) 3659, https://doi.org/
10.3390/s23073659.

[42] L. Hou, F. Yin, S. Wang, J. Sun, H. Yin, A review of thermal effects and substrate
damage control in laser cleaning, Opt. Laser Technol. 174 (2024) 110613,
https://doi.org/10.1016/j.optlastec.2024.110613.

[43] A.A. Cenna, P. Mathew, Evaluation of cut quality of fibre-reinforced plastics—A
review, Int J Mach Tool Manu 37 (6) (1997) 723–736, https://doi.org/10.1016/
S0890-6955(96)00085-5.

[44] J. Gu, X. Su, W. Li, Y. Jin, J. Xu, B. Guo, Process and mechanism of paint stripping
on CFRP by UV nanosecond laser, Opt. Laser Technol. 171 (2024) 110461,
https://doi.org/10.1016/j.optlastec.2023.110461.

[45] Y. Lu, L. Yang, M. Wang, Y. Wang, Improved thermal stress model and its
application in ultraviolet nanosecond laser cleaning of paint, Appl. Opt. 59 (25)
(2020) 7652, https://doi.org/10.1364/AO.398101.

[46] Z. Zhao, X. Liu, J. Yang, W. Pan, Y. Li, F. Liang, Y. Tian, L. Liu, F. Song, Shape
evolution and characteristics of carbon fiber reinforced polymer surface in laser
ablation, Vacuum 217 (2023) 112572, https://doi.org/10.1016/j.
vacuum.2023.112572.

[47] Gamaly, E. (2011). Femtosecond laser-matter interaction: Theory, experiments
and applications (1st ed.). Jenny Standford Publishing. 10.1201/9789814267809.

[48] J. Brand, A.V. Rode, S. Madden, A. Wain, P.L. King, L. Rapp, Ultrashort pulsed
laser ablation of granite for stone conservation, Opt. Laser Technol. 151 (2022)
108057, https://doi.org/10.1016/J.OPTLASTEC.2022.108057.

[49] J. Brand, A. Wain, A.V. Rode, S. Madden, L. Rapp, Towards safe and effective
femtosecond laser cleaning for the preservation of historic monuments, Appl.
Phys. A 129 (4) (2023) 246, https://doi.org/10.1007/s00339-023-06455-x.

[50] M. Kono, K.G.H. Baldwin, A. Wain, A. Rode, v., Treating the untreatable in art
and heritage materials: Ultrafast laser cleaning of “cloth-of-Gold”, Langmuir 31
(4) (2015) 1596–1604, https://doi.org/10.1021/LA504400H.

[51] T. Rivas, A.J. Lopez, A. Ramil, S. Pozo, M.P. Fiorucci, M.E.L. de Silanes, A. García,
J.R.V. de Aldana, C. Romero, P. Moreno, Comparative study of ornamental
granite cleaning using femtosecond and nanosecond pulsed lasers, Appl. Surf. Sci.
278 (2013) 226–233, https://doi.org/10.1016/j.apsusc.2012.12.038.

[52] M. Walczak, M. Oujja, L. Crespo-Arcá, A. García, C. Méndez, P. Moreno,
C. Domingo, M. Castillejo, Evaluation of femtosecond laser pulse irradiation of
ancient parchment, Appl. Surf. Sci. 255 (5 PART 2) (2008) 3179–3183, https://
doi.org/10.1016/j.apsusc.2008.09.011.

[53] V. Oliveira, S.P. Sharma, M.F.S.F. de Moura, R.D.F. Moreira, R. Vilar, Surface
treatment of CFRP composites using femtosecond laser radiation, Opt. Lasers Eng.
94 (2017) 37–43, https://doi.org/10.1016/j.optlaseng.2017.02.011.

[54] F.L. Palmieri, R.I. Ledesma, J.G. Dennie, T.J. Kramer, Y. Lin, J.W. Hopkins, C.
J. Wohl, J.W. Connell, Optimized surface treatment of aerospace composites
using a picosecond laser, Compos. B Eng. 175 (2019) 107155, https://doi.org/
10.1016/j.compositesb.2019.107155.

[55] K. Sugioka, Progress in ultrafast laser processing and future prospects,
Nanophotonics 6 (2) (2017) 393–413, https://doi.org/10.1515/NANOPH-2016-
0004.

[56] A. Wolynski, T. Herrmann, P. Mucha, H. Haloui, J. L’huillier, Laser ablation of
CFRP using picosecond laser pulses at different wavelengths from UV to IR, Phys.
Procedia 12 (2011) 292–301, https://doi.org/10.1016/j.phpro.2011.03.136.

[57] V. Bhaskar, D. Kumar, K.K. Singh, Laser processing of glass fiber reinforced
composite material: a review, Aust. J. Mech. Eng. 17 (2) (2019) 95–108, https://
doi.org/10.1080/14484846.2017.1363989.

[58] J. Cheng, J. Liao, Z. Yang, F. Xie, Y. Chen, H. Du, D. Liu, Laser stripping of
functional coatings on glass fiber reinforced plastic substrate, Appl. Opt. 61 (27)
(2022) 7867, https://doi.org/10.1364/AO.468960.

[59] J. Gu, X. Su, Y. Jin, W. Li, Z. Zeng, D. Zhang, J. Xu, B. Guo, Towards low-
temperature laser paint stripping by photochemical mechanism on CFRP
substrates, J. Manuf. Process. 85 (2023) 272–280, https://doi.org/10.1016/j.
jmapro.2022.11.041.

[60] B. Rauh, S. Kreling, M. Kolb, M. Geistbeck, S. Boujenfa, M. Suess, K. Dilger, UV-
laser cleaning and surface characterization of an aerospace carbon fibre
reinforced polymer, Int. J. Adhes. Adhes. 82 (2018) 50–59, https://doi.org/
10.1016/J.IJADHADH.2017.12.016.

[61] P. Karlitschek, G. Hillrichs, K.-F. Klein, Photodegradation and nonlinear effects in
optical fibers induced by pulsed uv-laser radiation, Opt. Commun. 116 (1–3)
(1995) 219–230, https://doi.org/10.1016/0030-4018(95)00057-F.

[62] K. Takahashi, M. Tsukamoto, S. Masuno, Y. Sato, H. Yoshida, K. Tsubakimoto,
H. Fujita, N. Miyanaga, M. Fujita, H. Ogata, Influence of laser scanning conditions
on CFRP processing with a pulsed fiber laser, J. Mater. Process. Technol. 222
(2015) 110–121, https://doi.org/10.1016/j.jmatprotec.2015.02.043.

[63] D. Zhang, J. Xu, Z. Li, K. Li, C. Wang, D. Shan, B. Guo, Removal mechanism of
blue paint on aluminum alloy substrate during surface cleaning using nanosecond
pulsed laser, Opt. Laser Technol. 149 (2022) 107882, https://doi.org/10.1016/J.
OPTLASTEC.2022.107882.

[64] D.C. Kirsch, S. Chen, R. Sidharthan, Y. Chen, S. Yoo, M. Chernysheva, Short-wave
IR ultrafast fiber laser systems: Current challenges and prospective applications,
J. Appl. Phys. 128 (18) (2020), https://doi.org/10.1063/5.0023936.

[65] J. Schille, U. Loeschner, Ultrashort pulse lasers in high-rate laser micro processing
– Quo vadis? Advanced Optical Technologies 10 (4–5) (2021) 233–237, https://
doi.org/10.1515/aot-2021-0049.

[66] J.-E. Kim, J.-M. Lee, J.-H. Hyun, J.-H. Jeong, J.-D. Kim, A Study on the Laser
Removal of Epoxy Coatings on SS400 Surface by Beam Scanning Patterns,
Coatings 11 (12) (2021) 1510, https://doi.org/10.3390/coatings11121510.

[67] J.-E. Kim, M.-K. Song, M.-S. Han, J.-D. Kim, A study on the application of laser
cleaning process in shipbuilding industries using 100 W fiber laser, J. Mech. Sci.
Technol. 35 (4) (2021) 1421–1427, https://doi.org/10.1007/s12206-021-0113-
3.

[68] L. Liu, X. Liu, L. Kong, M. Wang, P. Hu, D. Wang, Effect of laser surface treatment
on surface and bonding properties of carbon fiber reinforced composites, Int. J.
Mater. Form. 13 (6) (2020) 885–895, https://doi.org/10.1007/s12289-019-
01509-z.

[69] Y. Liu, W. Liu, D. Zhang, Z. Tian, X. Sun, Z. Wei, Experimental investigations into
cleaning mechanism of ship shell plant surface involved in dry laser cleaning by
controlling laser power, Appl. Phys. A 126 (11) (2020) 866, https://doi.org/
10.1007/s00339-020-04050-y.

[70] Md. Shamsujjoha, S.R. Agnew, J.R. Brooks, T.J. Tyler, J.M. Fitz-Gerald, Effects of
laser ablation coating removal (LACR) on a steel substrate: Part 2: Residual stress
and fatigue, Surf. Coat. Technol. 281 (2015) 206–214, https://doi.org/10.1016/j.
surfcoat.2015.02.034.

[71] Z. Tian, Z. Lei, X. Chen, Y. Chen, Evaluation of laser cleaning for defouling of
marine biofilm contamination on aluminum alloys, Appl. Surf. Sci. 499 (2020)
144060, https://doi.org/10.1016/J.APSUSC.2019.144060.

[72] Z. Tian, J. Feng, X. Chen, Z. Lei, Y. Chen, Hybrid laser cleaning characteristic of
marine barnacles fouling attached on Al alloys, J. Laser Appl. 33 (4) (2021)
042036, https://doi.org/10.2351/7.0000424.

A. Moreno-Madariaga et al.

https://doi.org/10.1007/s00339-011-6696-2
https://doi.org/10.1007/s00339-011-6696-2
https://doi.org/10.1016/j.apsusc.2012.09.110
https://doi.org/10.1016/j.apsusc.2012.09.110
https://doi.org/10.1007/S00339-011-6690-8/FIGURES/34
https://doi.org/10.1007/S00339-011-6690-8/FIGURES/34
https://doi.org/10.1007/978-1-84996-062-5_11
https://doi.org/10.2351/7.0001127
https://doi.org/10.1002/aisy.202200130
https://doi.org/10.1007/s00170-023-11535-6
https://doi.org/10.1007/s00170-023-11535-6
https://doi.org/10.1016/j.optlaseng.2022.107284
https://doi.org/10.1016/j.optlaseng.2022.107284
https://doi.org/10.1088/1742-6596/1748/2/022027
https://doi.org/10.1088/1742-6596/1748/2/022027
https://doi.org/10.1007/s11106-016-9772-5
https://doi.org/10.1007/s11106-016-9772-5
https://doi.org/10.1016/J.OPTLASTEC.2019.04.037
https://doi.org/10.1016/j.compositesa.2019.02.025
https://doi.org/10.1016/J.OPTLASTEC.2017.01.031
https://doi.org/10.1016/J.OPTLASTEC.2017.01.031
https://doi.org/10.1364/AO.404030
https://doi.org/10.1016/j.vacuum.2023.111927
https://doi.org/10.1016/j.vacuum.2023.111927
https://doi.org/10.1007/s00339-014-8527-8
https://doi.org/10.1016/j.mtcomm.2024.109312
https://doi.org/10.3390/s23073659
https://doi.org/10.3390/s23073659
https://doi.org/10.1016/j.optlastec.2024.110613
https://doi.org/10.1016/S0890-6955(96)00085-5
https://doi.org/10.1016/S0890-6955(96)00085-5
https://doi.org/10.1016/j.optlastec.2023.110461
https://doi.org/10.1364/AO.398101
https://doi.org/10.1016/j.vacuum.2023.112572
https://doi.org/10.1016/j.vacuum.2023.112572
https://doi.org/10.1016/J.OPTLASTEC.2022.108057
https://doi.org/10.1007/s00339-023-06455-x
https://doi.org/10.1021/LA504400H
https://doi.org/10.1016/j.apsusc.2012.12.038
https://doi.org/10.1016/j.apsusc.2008.09.011
https://doi.org/10.1016/j.apsusc.2008.09.011
https://doi.org/10.1016/j.optlaseng.2017.02.011
https://doi.org/10.1016/j.compositesb.2019.107155
https://doi.org/10.1016/j.compositesb.2019.107155
https://doi.org/10.1515/NANOPH-2016-0004
https://doi.org/10.1515/NANOPH-2016-0004
https://doi.org/10.1016/j.phpro.2011.03.136
https://doi.org/10.1080/14484846.2017.1363989
https://doi.org/10.1080/14484846.2017.1363989
https://doi.org/10.1364/AO.468960
https://doi.org/10.1016/j.jmapro.2022.11.041
https://doi.org/10.1016/j.jmapro.2022.11.041
https://doi.org/10.1016/J.IJADHADH.2017.12.016
https://doi.org/10.1016/J.IJADHADH.2017.12.016
https://doi.org/10.1016/0030-4018(95)00057-F
https://doi.org/10.1016/j.jmatprotec.2015.02.043
https://doi.org/10.1016/J.OPTLASTEC.2022.107882
https://doi.org/10.1016/J.OPTLASTEC.2022.107882
https://doi.org/10.1063/5.0023936
https://doi.org/10.1515/aot-2021-0049
https://doi.org/10.1515/aot-2021-0049
https://doi.org/10.3390/coatings11121510
https://doi.org/10.1007/s12206-021-0113-3
https://doi.org/10.1007/s12206-021-0113-3
https://doi.org/10.1007/s12289-019-01509-z
https://doi.org/10.1007/s12289-019-01509-z
https://doi.org/10.1007/s00339-020-04050-y
https://doi.org/10.1007/s00339-020-04050-y
https://doi.org/10.1016/j.surfcoat.2015.02.034
https://doi.org/10.1016/j.surfcoat.2015.02.034
https://doi.org/10.1016/J.APSUSC.2019.144060
https://doi.org/10.2351/7.0000424


Optics and Laser Technology 180 (2025) 111479

15

[73] D. Ciofini, M. Martínez-Weinbaum, M. Castillejo, M. Oujja, C. Chillé, S. Siano,
I. Osticioli, Quantitative spectroscopic characterization of laser-induced effects on
oil paint films using 213, 266, or 2940 nm, J. Cult. Herit. 66 (2024) 155–165,
https://doi.org/10.1016/j.culher.2023.11.015.

[74] S. Samolik, M. Walczak, M. Plotek, A. Sarzynski, I. Pluska, J. Marczak,
Investigation into the removal of graffiti on mineral supports: Comparison of
nanosecond Nd:YAG laser cleaning with traditional mechanical and chemical
methods, Stud. Conserv. 60 (2015) S58–S64, https://doi.org/10.1179/
0039363015Z.000000000208.

[75] S. Kalpakjian, S. Schmid, V. Sekar, Manufacturing Engineering and Technology,
(7th edition)., Pearson Publications, 2013.

[76] M.P. Groover, Fundamentals of Modern Manufacturing: Materials, Processes, and
Systems (Fourth Edition), John Wiley & Sons Inc, 2010.

[77] UNE-EN ISO 25178-2:2013 Especificación geométrica de productos... (n.d.).
Retrieved December 26, 2021, from https://www.une.org/encuentra-tu-norma/
busca-tu-norma/norma?c=N0051160.

[78] UNE-EN 828:2013 Adhesivos. Mojabilidad. Determinación por medi... (n.d.).
Retrieved December 26, 2021, from https://www.une.org/encuentra-tu-norma/
busca-tu-norma/norma?c=N0051185.

[79] Nandiyanto, A. B. D., Oktiani, R., & Ragadhita, R. (2019). How to Read and
Interpret FTIR Spectroscope of Organic Material. Indonesian Journal of Science
and Technology, 4(1), 97. 10.17509/ijost.v4i1.15806.

[80] M. Al-Amin, S. Chandra Dey, T.U. Rashid, M. Ashaduzzaman, S.M. Shamsuddin,
Solar Assisted Photocatalytic Degradation of Reactive Azo Dyes in Presence of
Anatase Titanium Dioxide, International Journal of Latest Research in
Engineering and Technology 2 (2016) 14–21.

[81] M. Simon, A. Vianello, Y. Shashoua, J. Vollertsen, Accelerated weathering affects
the chemical and physical properties of marine antifouling paint microplastics
and their identification by ATR-FTIR spectroscopy, Chemosphere 274 (January)
(2021) 129749, https://doi.org/10.1016/j.chemosphere.2021.129749.

[82] M. Lagerström, E. Ytreberg, A.-K.-E. Wiklund, L. Granhag, Antifouling paints
leach copper in excess – study of metal release rates and efficacy along a salinity
gradient, Water Res. 186 (2020) 116383, https://doi.org/10.1016/j.
watres.2020.116383.

[83] C.A. Paz-Villarraga, Í.B. Castro, G. Fillmann, Biocides in antifouling paint
formulations currently registered for use, Environ. Sci. Pollut. Res. 29 (20) (2022)
30090–30101, https://doi.org/10.1007/s11356-021-17662-5.

[84] F.B. Reig, J.V.G. Adelantado, M.C.M. Moya Moreno, FTIR quantitative analysis of
calcium carbonate (calcite) and silica (quartz) mixtures using the constant ratio
method, Application to Geological Samples. Talanta 58 (4) (2002) 811–821,
https://doi.org/10.1016/S0039-9140(02)00372-7.

[85] P.K. Raul, S. Senapati, A.K. Sahoo, I.M. Umlong, R.R. Devi, A.J. Thakur, V. Veer,
CuO nanorods: A potential and efficient adsorbent in water purification, RSC Adv.
4 (76) (2014) 40580–40587, https://doi.org/10.1039/c4ra04619f.

[86] M. Shafiey Dehaj, M. Zamani Mohiabadi, Experimental study of water-based CuO
nanofluid flow in heat pipe solar collector, J. Therm. Anal. Calorim. 137 (6)
(2019) 2061–2072, https://doi.org/10.1007/s10973-019-08046-6.

[87] M.R. Johan, M.S.M. Suan, N.L. Hawari, H.A. Ching, Annealing effects on the
properties of copper oxide thin films prepared by chemical deposition, Int. J.
Electrochem. Sci. 6 (12) (2011) 6094–6104, https://doi.org/10.1016/s1452-
3981(23)19665-9.

[88] A. Artesani, F. Gherardi, A. Nevin, G. Valentini, D. Comelli, A photoluminescence
study of the changes induced in the zinc white pigment by formation of zinc
complexes, Materials 10(4)340 (2017), https://doi.org/10.3390/ma10040340.

[89] G.A. Bowmaker, J.V. Hanna, IR Spectroscopy of Two Polymorphs of Copper(I)
Thiocyanate and of Complexes of Copper(I) Thiocyanate with Thiourea and
Ethylenethiourea, Zeitschrift Fur Naturforschung - Section B Journal of Chemical
Sciences 64 (11–12) (2009) 1478–1486, https://doi.org/10.1515/znb-2009-11-
1231.

[90] A. Moreno, A.J. López, J. Lamas, A. Ramil, Femtosecond pulsed laser ablation for
paint removal at oblique illumination: Effect of the incidence angle, Optik 264
(June) (2022) 169428, https://doi.org/10.1016/j.ijleo.2022.169428.

[91] K. Ziętkowska, R. Kozera, B. Przybyszewski, A. Boczkowska, B. Sztorch,
D. Pakuła, B. Marciniec, R.E. Przekop, Hydro- and Icephobic Properties and
Durability of Epoxy Gelcoat Modified with Double-Functionalized Polysiloxanes,
Materials 16 (2) (2023) 875, https://doi.org/10.3390/ma16020875.

[92] R. Ellerbrock, M. Stein, J. Schaller, Comparing amorphous silica, short-range-
ordered silicates and silicic acid species by FTIR, Sci. Rep. 12 (1) (2022) 1–8,
https://doi.org/10.1038/s41598-022-15882-4.

[93] D.B. Mawhinney, J.A. Glass, J.T. Yates, FTIR study of the oxidation of porous
silicon, J. Phys. Chem. B 101 (7) (1997) 1202–1206, https://doi.org/10.1021/
jp963322r.

[94] A. Riveiro, A.L.B. Maçon, J. del Val, R. Comesaña, J. Pou, Laser surface texturing
of polymers for biomedical applications, Front. Phys. 5 (FEB) (2018), https://doi.
org/10.3389/fphy.2018.00016.

[95] D. Sola, R. Cases, High-repetition-rate femtosecond laser processing of acrylic
intra-ocular lenses, Polymers 12 (1) (2020) 1–9, https://doi.org/10.3390/
polym12010242.

[96] J. Brand, A. Wain, A.V. Rode, S. Madden, P.L. King, L. Rapp, Femtosecond pulse
laser cleaning of spray paint from heritage stone surfaces, Opt. Express 30 (17)
(2022) 31122, https://doi.org/10.1364/oe.468750.

[97] E. Almeida, T. Diamantino, O. de Sousa, Marine paints: The particular case of
antifouling paints, Prog. Org. Coat. 59 (1) (2007) 2–20, https://doi.org/10.1016/
J.PORGCOAT.2007.01.017.

[98] D. Quéré, Rough ideas on wetting, Physica A 313 (1–2) (2002) 32–46, https://
doi.org/10.1016/S0378-4371(02)01033-6.

[99] Al Balushi, K.M., Sefiane, K., & Orejon, D, Binary mixture droplet wetting on
micro-structure decorated surfaces, J. Colloid Interface Sci. 612 (2022) 792–805,
https://doi.org/10.1016/j.jcis.2021.12.171.

[100] A. Marmur, Wetting on Hydrophobic Rough Surfaces: To Be Heterogeneous or
Not To Be? Langmuir 19 (20) (2003) 8343–8348, https://doi.org/10.1021/
LA0344682.

[101] S. Banerjee, Simple derivation of Young, Wenzel and Cassie-Baxter Equations and
Its Interpretations. (2008). http://arxiv.org/abs/0808.1460.

[102] M. Nosonovsky, B. Bhushan, Superhydrophobic surfaces and emerging
applications: Non-adhesion, energy, green engineering, Curr. Opin. Colloid
Interface Sci. 14 (4) (2009) 270–280, https://doi.org/10.1016/j.
cocis.2009.05.004.

[103] A.J. López, J.S. Pozo-Antonio, A. Moreno, T. Rivas, D. Pereira, A. Ramil,
Femtosecond laser texturing as a tool to increase the hydrophobicity of
ornamental stone: The influence of lithology and texture, Journal of Building
Engineering 51 (2022) 104176, https://doi.org/10.1016/j.jobe.2022.104176.

[104] A.J. López, A. Ramil, J.S. Pozo-Antonio, T. Rivas, D. Pereira, Ultrafast laser
surface texturing: A sustainable tool to modify wettability properties of marble,
Sustainability 11 (15) (2019) 4079, https://doi.org/10.3390/su11154079.

A. Moreno-Madariaga et al.

https://doi.org/10.1016/j.culher.2023.11.015
https://doi.org/10.1179/0039363015Z.000000000208
https://doi.org/10.1179/0039363015Z.000000000208
http://refhub.elsevier.com/S0030-3992(24)00937-X/h0150
http://refhub.elsevier.com/S0030-3992(24)00937-X/h0150
http://refhub.elsevier.com/S0030-3992(24)00937-X/h0250
http://refhub.elsevier.com/S0030-3992(24)00937-X/h0250
http://refhub.elsevier.com/S0030-3992(24)00937-X/h0015
http://refhub.elsevier.com/S0030-3992(24)00937-X/h0015
http://refhub.elsevier.com/S0030-3992(24)00937-X/h0015
http://refhub.elsevier.com/S0030-3992(24)00937-X/h0015
https://doi.org/10.1016/j.chemosphere.2021.129749
https://doi.org/10.1016/j.watres.2020.116383
https://doi.org/10.1016/j.watres.2020.116383
https://doi.org/10.1007/s11356-021-17662-5
https://doi.org/10.1016/S0039-9140(02)00372-7
https://doi.org/10.1039/c4ra04619f
https://doi.org/10.1007/s10973-019-08046-6
https://doi.org/10.1016/s1452-3981(23)19665-9
https://doi.org/10.1016/s1452-3981(23)19665-9
https://doi.org/10.3390/ma10040340
https://doi.org/10.1515/znb-2009-11-1231
https://doi.org/10.1515/znb-2009-11-1231
https://doi.org/10.1016/j.ijleo.2022.169428
https://doi.org/10.3390/ma16020875
https://doi.org/10.1038/s41598-022-15882-4
https://doi.org/10.1021/jp963322r
https://doi.org/10.1021/jp963322r
https://doi.org/10.3389/fphy.2018.00016
https://doi.org/10.3389/fphy.2018.00016
https://doi.org/10.3390/polym12010242
https://doi.org/10.3390/polym12010242
https://doi.org/10.1364/oe.468750
https://doi.org/10.1016/J.PORGCOAT.2007.01.017
https://doi.org/10.1016/J.PORGCOAT.2007.01.017
https://doi.org/10.1016/S0378-4371(02)01033-6
https://doi.org/10.1016/S0378-4371(02)01033-6
https://doi.org/10.1016/j.jcis.2021.12.171
https://doi.org/10.1021/LA0344682
https://doi.org/10.1021/LA0344682
http://arxiv.org/abs/0808.1460
https://doi.org/10.1016/j.cocis.2009.05.004
https://doi.org/10.1016/j.cocis.2009.05.004
https://doi.org/10.1016/j.jobe.2022.104176
https://doi.org/10.3390/su11154079

	Femtosecond laser removal of antifouling paints on glass fibre reinforced plastic used in maritime industry
	1 Introduction
	2 Materials and methods
	2.1 Samples preparation
	2.2 Femtosecond laser system
	2.3 Analytical techniques
	2.3.1 Optical microscopy
	2.3.2 Scanning electron microscopy (SEM)
	2.3.3 Fourier transform infrared spectroscopy FTIR
	2.3.4 Interferometric microscopy
	2.3.5 Contact angle measurement


	3 Results and discussion
	3.1 Samples characterization
	3.2 Laser paint removal
	3.2.1 Efficiency of paint removal
	3.2.2 SEM-EDS and ATR analysis

	3.3 Surface morphology characterization
	3.4 Wettability evaluation

	4 Conclusions
	CRediT authorship contribution statement
	Declaration of competing interest
	Data availability
	Funding and Acknowledgements
	Appendix A Supplementary data
	References