Controlled construction of flexible thermoelectric composite films with submicron porous structure

A bstract: To study polymer-based films with excellent flexibility and thermoelectric properties, we controllably construct poly (3, 4-ethylenedioxythiophene) -tosylate/polyether sulfone (PEDOT-Tos/PES) thermoelectric composite films with submicron porous structure by vapor-phase polymerization using a PES flexible filter membrane as the substrate. The effects of oxidant mass fraction (10% ~ 25%) and polymerization time on the microstructure and thermoelectric properties of the composite films are investigated. Accordingly, an optimized PEDOT-Tos/PES composite film with submicron porous structure and excellent thermoelectric properties is obtained with an oxidant mass fraction of 20% and a polymerization time of 2. 5 h. The prepared composite film exhibits a high electrical conductivity of (274 ± 9) S/m and a large Seebeck coefficient of (13. 8 ± 0. 5) μV/K. Moreover, it also displays excellent stable thermoelectric properties upon various mechanical bending cycles. This study provides a simple and feasible strategy for the preparation of free-standing conducting polymer-based films with excellent flexibility and thermoelectric properties.