Novel electro-active shape memory polymers for soft actuators

Abstract

A novel electro-active shape memory polymer (SMP) was fabricated with fully soluble self-doped poly(3,4-ethylenedioxythiophene) (S-PEDOT) and SMP using a solution mixing method at various S-PEDOT weight ratios (WS-PEDOT). The percolation analysis showed an extreme low percolation threshold of 0.38 vol% and critical exponent of 1.15, which was associated with the S-PEDOT conductive networks formed by phase separation in the S-PEDOT:SMP composite. The shape memory characteristics were observed at WS-PEDOT ≤ 30 wt%, while the glass transition temperature (Tg) was almost constant ca. 50 °C. The S-PEDOT:SMP composite film at WS-PEDOT = 10 wt% showed electrical conductivity (σ), shape fixing ratio (Rf), and shape recovery ratio (Rr) of 29 S cm−1, 95.4%, and 90.1%, respectively. Furthermore, an electro-active SMP soft actuator, fabricated using the S-PEDOT:SMP composite film at WS-PEDOT = 10 wt%, quickly recovered from a temporary bent shape to its original open shape within 5 s upon application of 6 V.