Synthesis of Water- and Humidity-Responsive Liquid Crystal Elastomers and Their 4D Printing
발표자
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초록
내용
In this study, we synthesized a water- and humidity-responsive liquid crystal elastomer (LCE) by aza-Michael addition using N,N’-dimethylethylenediamine, followed by photopolymerization. To enable water and humidity responsiveness, the top surface of aligned LCE film was activated by acidic solution which generated cations on the surface, resulting in increased hydrophilicity. Due to anisotropic mechanical properties and asymmetric hydrophilicity, a macroscopically aligned LCE film underwent bending when exposed to water or humidity. The shape changes can be also controlled by the cutting angle with respect to the nematic director as well as by localizing the activated areas of the LCE film. Lastly, we have successfully fabricated humidity-responsive 3D-printed LCEs via UV-assisted direct-ink-writing. Our water and humidity-responsive shape programmable LCEs can find interesting applications in sensors, smart textiles and biomedical devices.