Emulsion Hydrogel Soft Motor Actuated by Thermal Stimulation.

An emulsion hydrogel motor (E-H motor), constituted by low-boiling-point oil fuel and a hydrogel matrix, is prepared through a simple yet versatile oil-in-water (O/W) emulsion template method. The E-H motor can be efficiently propelled by the bubbles generated under a thermal stimulus. As thermally induced explosion occurs inside the E-H motor (diameter ∼4.0 mm and length ∼6.0 mm), the gas bubbles resulting from thermotropic phase transition are violently ejected from one side, leading to a fast speed of 14.78 ± 4.82 mm s-1 in a 60 °C aqueous solution. Additionally, multiple water-insoluble organic solvents can serve as the fuel for self-propulsion, which demonstrates the favorable universality of the E-H motor. The magnetic navigation and near-infrared propulsion can be realized through incorporating hydrophilic iron oxide (Fe3O4) nanoparticles and graphene oxide (GO) into the aqueous phase. Moreover, the synchronous integration of GO and enrofloxacin bactericide can enable intelligent targeted cargo transportation and delivery. The attractive self-propulsion performance, precise locomotion control, and formidable integration ability of the emulsion hydrogel-based miniaturized soft motor hold great promise for numerous practical applications.