Multifunctional electromechanical and thermoelectric polyaniline-poly(vinyl acetate) latex composites for wearable devices

Abstract

This paper reports on the piezoresistive, thermoresistive and thermoelectric behaviour of polymer-based nanocomposites, composed of polyaniline and poly(vinylacetate) latex (PANI/PVAc) matrix. The samples were prepared by simple, scalable, eco-friendly and low-cost latex technology with PANI concentrations spanning form 2.5 to loadings of 60 wt.%. The observed electrical and mechanical behaviour can be explained in the framework of the percolation theory. Specifically, stretchable PANI/PVAc films with PANI contents ranging from 10 to 30 wt.% are particularly useful for applications involving electrical conductivity with elastomeric performance. Due to the combination of the reinforcement effect of PANI and enhanced interfacial adhesion via H-bonding between PANI and the polymer matrix, they present higher Young´s modulus and tensile strength together with a slight decrease in ductility, compared to pure PVAc latex. PANI/PVAc ratio plays an important role in the electromechanical composites, both in the GF values and fatigue. Accordingly, the mechanical properties of PVAc latex, tailored with conductive PANI, can develop interesting electromechanical properties for sensors devices up to large deformations. This tunability together with the soft nature of composites paves the way for low-cost macroscale diverse and adaptable applications such as temperature sensing, mapping, and compensation in stretchable and wearable electronics.