Fabrication And Application Of Polymer-based Micromotors And Micropumps

In recent years,the micromachines which are capable of moving autonomously in the liquid environment or pumping the surrounding fluids,have attracted more and more attention.Generally speaking,micromotor and micropump are two different types of micromachines.Micromotor mimic the biological motor,which is a nano-or microscale device and can convert chemical,physical and other energy into mechanical energy,resulting in spatial movement of the microdevice.On the other hand,micropump represents another type of micromachine,which can drive the surrounding fluids and particles.However,the fabrication of micromotor and micropump is relatively complicated,compared with the reported method.Besides,the materials for micromotors and micropumps are not biocompatible,which limited the application of micromotor and micropump in the fields of drug transportation,environmental remediation and microfluidics.On the basis of the above,this thesis uses a simple synthesis method to fabricate micromotor with biological compatibility.We fabricated the micromotors and studied their application in pH sensing and environmental remediation.We also fabricated a binary micropump and studied its application in smart window and long-range transportation.The work of this thesis is divided into the following three parts.1?A cartridge-case-like structure is constructed by the template synthesis method.The cartridge-case-like structure consists of a gelatin shell with platinum nanoparticles decorating its inner surface.Due to the catalytic activity and the pH responsiveness originating from the platinum nanoparticle and the gelatin,the resulting cartridge-case-like structure can not only move autonomously in the presence of the hydrogen peroxide fuel but also exhibit the pH-dependent motion behavior.The moving velocity increases proportionately with the increase of pH.By studying the morphology and motion differences under different pH conditions,we find out that the unique sensing phenomenon relies on the pH-dependent catalytic activity and the swelling behavior originating from the PtNPs and the gelatin(pH-dependent catalytic activity of PtNPs and the swelling behavior of the gelatin),respectively.Our current work not only illustrates how the property of the constituent parts may influence the motion behavior of a micromotor under different conditions but also paves the way toward the further development of motion-based sensors.2.We fabricate a porous microsphere by electrospinning method.The structure is made up of catalase and polycaprolactone.The hydrogen peroxide can be decomposed by the catalase,resulting that the micromotor exhibits autonomous movement in the presence of the hydrogen peroxide fuel.Due to the hydrophobic nature of the polymer biocompatible to the micromotor,the autonomous moving micromotor can attach spilled oil droplet dispersed in the solution through hydrophobic hydrophobic interreaction once it collides with the oil droplet.Therefore,the fabrication of the current multiple functional micromotor not only greatly simplifies the construction of a micromotor,but also holds great promise in the field of environmental remediation due to the bio-friendly nature of the current biopolymer-based micromotor.3?Micropump refers to a microdevice which can induce the flow of its surrounding fluids.We fabricate a binary micropump based on the electrospinning technology,which consists of perovskite and poly[(2-methoxy-5-ethylhexyloxy)-1,4-phenylenevinylene](MEHPPV).The micropump has a pancake-like shape and is operational under the influence of light.Light shows great versatility in controlling the pumping phenomenon of the micropump.It not only gove rns the start and stop but also regulates the velocity and directions.The direction control opens up a great opportunity for the development of micropumps with unprecedented pumping behaviors and functions(such as heartbeat-like pumping,rectification and amplification),making them potentially useful in various fields.We thus believe the micropump reported in the current study shows a key step toward the further development of more sophisticated micropumps for diverse applications.