Preparation and properties of PEDOT:PSS/poly(acrylamide-co-methacrylic acid) conductive hydrogels

In this work, in-situ free-radical solution polymerization method was used to fabricate poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/poly(acrylamide-co-methacrylic acid) (P(AAM-MAA)) conductive hydrogels. The composition and morphology were characterized by FTIR, Raman, TGA, and SEM, respectively. The visible-light transmittance, electrical conductivity, tensile properties, and strain sensitivity were also tested. The results show that PEDOT:PSS is well dispersed in the P(AAM-MAA) hydrogel network, and the hydrogel shows good conductivity and transparency (>50%). The introduction of MAA not only improves the electrical conductivity but also enhances the tensile properties and strain sensitivity of the hydrogel. When the amount of MAA increases from 0wt% to 2.52wt%, the conductivity of PEDOT:PSS/P(AAM-MAA) rises from 0.043 S·m⁻¹ to 0.060 S·m⁻¹, and the tensile strength, elongation at break increases from 46 kPa, 76% to 68 kPa, 129%, respectively. PEDOT:PSS/P(AAM-MAA) also has demonstrated excellent linear sensitivity (R²>0.983) (strain: 0%-70%). The resistance variation curve shows that the prepared hydrogels can be used as sensors to monitor various small movements of human body through the resistance signal change.