Temperature Controlled Self-Folding Design Using Thermo-Sensitive Hydrogel Pnipam

Abstract

PNIPAM, a typical thermo-sensitive hydrogel, possesses the ability to swell significantly under its lower critical solution temperature (LCST), offering a novel way to assembly 3D film structures. To clarify the mechanism of the assembly process, we apply PNIPAM to thin rectangular bilayers with another hydrophobic polymer polycaprolactone (PCL), which can turn into self-bending curved bridges in 25 °C aqueous environment. This simple bilayer geometry makes it possible from 2D to 3D automatically and can be applied to thermally responsive actuation of micro-devices. Then we proposed a self-folding table-like structure which is thermally responsive. Moreover, the finite element analysis (FEA) and experiments are employed to validate the assembly process. The design concepts and simulation techniques may serve as the guidelines for the thermal driven assembly design.