Self-Propelling Hydrogel Motors And Their Applications

We fabricate a kind of catalytic self-propelling hydrogel soft motors（H-motors）via a facile injection loading method with low energy consumption.The factors influencing the practicability of H-motors,including locomotive ability and reusability are investigated.The succession of rapid bubble evolution and propulsion endows the millimetre-sized columnar H-motors with length/diameter=1 a remarkable speed of 3.84 mm s^-1 in 10%（w/w）hydrogen peroxide（H2O2）solution.Moreover,the H-motors maintain undiminished propulsion capability and functionality even after repeated loading for 6 times.Additionally,we also fabricate emulsion-hydrogel soft motors（E-H-motors）templated from the oil/water（O/W）emulsion for the first time,which exhibit a faster speed of 4.33 mm s^-1 under the same conditions.It can be ascribed to the additional liberation of low-boiling oil phase stored in the emulsion-hydrogels caused by catalytic reaction heat,which is appropriate for larger propulsive situation.The stabilized,efficient and reusable H-motors are selected for industrial effluents purification to fit the imperious demands about the disposal of organic pollutants in water.The synergy effect between catalytic degradation and enhanced intermixing of the fluid flow around the miniaturized soft motors gives rise to an effective and exhaustive removal of organic contaminants.In the further work,a novel thermal-driven emulsion hydrogel motor（E-H-motor）was fabricated through a simple yet versatile oil-in-water（O/W）emulsion template method,which displayed a remarkable self-driven ability,favorable universality and strong integration capability.As thermal-inducted explosion occurred inside E-H-motor（diameter ～4.0 mm,length ～6.0 mm）,the oil bubbles resulting from thermotropic phase transition were violently ejected from the tail of it,which led to a fast speed of 14.78 ± 4.82 mm s^-1 at 60 ℃ pure water.Additionally,multiple water-insoluble organic solvents could serve as the oil fuel of self-propulsion that demonstrate the favorable universality of E-H-motor.By virtue of the intrinsic integration and encapsulation capability of the O/W emulsion hydrogel,we incorporated the hydrophilic iron oxide（Fe₃O₄）nanoparticles and graphene oxide（GO）into aqueous phase,achieving the functions of magnetic navigation and near-infrared（NIR）remotely driving.Moreover,as an introduce-of-new-concept,we synchronously integrated GO and enrofloxacin bactericide into the E-H-motor and realized an NIR-controlled sterilization platform as well as a targeted transportation and delivery,which made the integrated motor acting as an intelligent bacteria processor.The attractive fuel-contained propulsion performance,precise locomotion control,sensitive triggering release,and formidable integration ability of the emulsion hydrogel based miniaturized soft-motor hold great promising for multiple practical applications.