Nature-Inspired Janus Actuators with Structurally Engineered PEDOT:PSS

Inspired by natural systems such as pinecones and seedpods, bilayer actuators enable programmable shape transformations through differential responses to external stimuli, making them promising for soft robotics and adaptive devices. However, issues such as interfacial delamination, high driving voltages, and excessive heat generation hinder their practical use. Here, a facile strategy is developed to fabricate a high-performance poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) Janus actuator capable of large, reversible bending deformation in response to electrical current, heat, humidity, and organic vapor. The actuator features a seamless interface between a conductive, hydrophobic-treated layer and a semiconductive, hydrophilic untreated layer, effectively eliminating delamination common in bilayer structures. This structural engineering is enabled by a novel "dual treatment" approach that combines solvent doping and acid post-treatment, producing a substantial conductivity contrast (≈2000 S cm^-1) between the two sides while preserving structural integrity. The resulting actuator exhibits excellent electro-thermo-mechanical performance, achieving reversible curvature values of 2.4 to 3.4 cm^-1 at low operating voltages (2 to 6 V) with minimal surface heating (≈5 °C). It also demonstrates outstanding durability over 2,400 actuation cycles. This work introduces a scalable and energy-efficient design platform for next-generation soft actuators, bio-inspired adaptive materials, and intelligent sensing systems.