Preparation of highly conductive flexible polyurethane elastomers with low PEDOT:PSS content based on a novel pore collapse strategy

Meeting the requirements of flexible electronic devices remains a challenge in achieving stable and highly conductive polymer composites (CPCs) with minimal loading poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). In this study, PEDOT:PSS based CPCs were prepared using a novel method involving pore collapse of aerogels. Initially, polyurethane aerogels (PUAs) were synthesized with varying pore sizes ranging from 4.14 nm to 5.13 nm based on specific formula ratios. Subsequently, solvent evaporation at 120 °C caused shrinkage and collapse of the PUAs' pore structure, resulting in the formation of a continuous conductive circuit composed of PEDOT:PSS in polyurethane elastomers (CPUEs). CPUEs containing 1.53 wt% PEDOT:PSS exhibited remarkably high conductivity characteristics (1590 S/m). These CPUEs demonstrated excellent mechanical flexibility as they could withstand stretching, bending, and twisting without significant changes in resistance or affecting LED brightness. Moreover, they proved suitable for use as soft electrodes for electrocardiography (ECG) during exercise to monitor heart rate. This work presents an innovative approach for constructing highly conductive networks through pore collapse of aerogels and obtaining low-loading conductive polymers.