The Interplay between Different Stimuli in a 4D Printed Photo‐, Thermal‐, and Water‐Responsive Liquid Crystal Elastomer Actuator

Abstract

Multi‐stimuli responsivity in 3D‐printed objects is receiving much attention. However, the simultaneous interplay between different environmental stimuli is largely unexplored. In this work, we demonstrate direct ink writing of an oligomeric ink containing an azobenzene photo‐switch with an accessible hydrogen bond allowing triple responsivity to light, heat, and water. The resulting printed liquid crystal elastomer performs multiple actuations, the specific response depending on the environmental conditions. Bilayer films formed by printing on a static substrate can rapidly change shape, bending almost 80 degrees if irradiated in air or undergoing a shrinkage of about 50 % of its length when heated. The bilayer film assumes dramatically different shapes in water depending on combined environmental temperature and lighting conditions.

Programmable Liquid Crystal Defects and Dynamically Manipulation with Mechanical Stress

“…[47,48] But the effect of a single external field is insufficient to meet more complex and precise regulation. As a result, multiple field interactions produce more possibilities, such as the response to external stimuli of light, temperature [49] and electric fields. [46,50] However, as conventional regulatory methods gradually approach their bottlenecks, new methods will expand the dimensions of manipulation, and the combined action of multiple fields will make further manipulation of topological structures possible.…”