Actuation of Hydrogel Architectures Prepared by Electrophoretic Adhesion of Thermoresponsive Microgels

Owing to their unique properties, hydrogels may be used for preparingsoft actuators. Soft actuators are expected to respond quickly; however, the responsespeed of gels is slow. To study this issue and overcome it, thermoresponsive softactuators were prepared by the electrophoretic adhesion of cationic and anionicthermoresponsive microgels, comprising poly(diallyldimethylammonium chloride) andpoly(styrenesulfonate) sodium salt, respectively. The kinetics of the prepared hydrogelarchitectures in response to temperature depended on the microgel diameter instead ofthe architecture size. We also prepared bilayered hydrogel architectures by adhesion ofthermoresponsive and/or nonthermoresponsive microgels. These bent rapidly inresponse to temperature because these architectures consisted of microgel assemblies.In addition, specific bending motion was demonstrated by the adhesion of microgellayers of different sizes. The present study provides not only a guideline for the design ofhydrogel actuators with quick response but also presents a method for the free-formfabrication of functional hydrogel materials that undergo complex motions in response to stimuli