The bending of porous PNIPAAm gels with deswelling-speed gradient by silicaconcentration gradient

Stimuli-responsive hydrogels have earned a reputation as "smart materials" change their volume or shape in response to an environmental signal. In the present study, we prepared "poregradient gel" which shows rapid bending in response to temperature change. The precursor of poregradient gels, gradient gels with silica concentration (silica-gradient gels) were prepared by electrophoresis of silica-suspended monomer solution in the presence of cross-linker and photo-initiator. After UV irradiation, the pore-gradient gels transcribed silica-gradient gel structures were obtained by the extraction of silica. The design of bending gels for thermoresponsive polymer gels is interesting for development of high-performance intelligent soft actuator.