Photocurable printed piezocapacitive pressure sensor based on an acrylic resin modified with polyaniline and lignin

Abstract

The design of suitable materials for the manufacture of pressure sensors withhigh sensitivity and flexibility in wearable electronics is still a challenge. In thisstudy, a flexible and portable pressure sensor is developed based on a pho-topolymeric formulation of polyaniline (PANI)/Lignin/acrylate. The amountof photoinitiator and the presence of lignin within the filler are investigated toobtain the best printability and capacitive response. Low PANI contents drasti-cally increase the dielectric constant and 4 wt% photoinitiator improves thesignal and sensitivity. A sensitivity of 0.012 kPa–1 is achieved in a linear range(0–10 kPa) with only 3.5 wt% PANI. Lignin improves both the dispersion of thefiller within the matrix and the printability of the resin, due to lower absorptivityat the UV wavelength of the 3D printer. Thus, the PANI-Lignin filler is selectedfor the fabrication of a piezocapacitive prototype transducer. The pressuretransducer demonstrate its practical application by responding to a humanfootfall and transmitting its corresponding electrical signal. This study showsthe enhanced properties of lignin modified PANI acrylate composites. Basedon lignin, an abundant natural waste, a sustainable photocurable cost-effectivepolymer is proposed for the fabrication of printable, wearable electronics.