Study On The Preparation And Performance Of Self-Propelled Polymer Janus Micromotor

Micromotors are tiny devices that can convert environmental energy（chemical reactions,light,electric field,magnetic field and others）into mechanical motion,which show broad application prospects in targeted drug delivery,non-invasive microsurgery,biosensing and environmental remediation.However,most of the existing techniques for fabricating micromotors involve complex processes and it is still challenging to prepare these micromotors at large scales,which will restrict its practical application.Here,basing on droplet microfluidics technology,self-propelled polymer micromotors with controllable shape and size were prepared on large-scale by using emulsions as the template.Then their movement behavior in fuel and performance of catalytic degradation of organic pollutant were studied.The specific research contents are as follows:（1）A one-step microfluidic method was developed to fabricate multifunctional polymer Janus micromotors.W/O/W double emulsion as the initial template was formed by the three-phase fluid in the microfluidic device.The evolution of the emulsion from initial core-shell structure to the desired shape was controlled by the composition of the organic mesophase.By adding functional nanoparticles to the inner phase and the middle fluid,the interface was independently controlled and further crosslinked after ultraviolet radiation to obtain the required multifunctional micromotor.The self propulsion characteristics of micromotors and catalytic degradation of organic pollutants in wastewater were systematically studied.（2）Based on microfluidic and solvent evaporation induced liquid-liquid separation method,Janus micromotor was prepared.Micromotors with controllable shape and size were developed for oxidative degradation of organic pollutants in wastewater.Using microfluidic emulsion as the template,monodispersed micromotors can be prepared in large quantities via phase separation and UV-induced monomer polymerization.By adjusting the volume ratio of two immiscible oil phases in the initial emulsion,the geometry of the micromotor can be precisely controlled,from nearly spherical,hemispherical to crescent.The size of the micromotor can be controlled by changing the fluid flow rates.In addition,by introducing functional nanoparticles into the asymmetric structure,the micromotor can be flexibly functionalized.（3）A microfiber-confined microfluidic method was proposed to controllably fabricate deformable droplets as templates for micromotors.The shape of the micromotor can be controlled from spherical,spindle to drum by changing the size and spacing of the deformable oil droplets in the alginate microfiber.In addition,the shape and size of the micromotor can be precisely adjusted by simply varying the flow rate of the fluid.By coating MnO₂ and magnetic Fe₃O₄ nanoparticles on the surface,the micromotor is endowed with dual functions of catalytic propulsion and magnetic guidance,which can perform complex tasks.The micromotor exhibits good degradation effect on methylene blue and can be recovered by magnet.In addition,this flexible strategy provides a facile method for finer control of particles,and has great prospect in various engineering applications.