Study On The Design And Preparation Of The Self-driven Micro Motor And The Movement Mechanism

With the rapid development of the global nanotechnology, research andapplications of nanotechnology and materials have been developed to span over thefields of bio-medicine, life sciences, textile processing, especially computers (which’sdevelopment was a driving force for nanotechnology) and many other fields. Artificialmicro motors are micro scale devices which can convert chemical energy intomechanical energy. Because of its huge potential application in switches, sensors anddrug delivery value, artificial motors already became one of the hottest research topics.In this thesis, molecular motor particles are investigated.The production of these plates was done by firstly producing a silicon master bymeans of conventional lithography. For the master production first CAD software todesign the basic pattern and size of the motor was painted and then the mask wasproduced. Utilizing standard photolithography to generate a patterned silicon substrateby hardening out the illuminated area and dissolving the non-crosslinked areas resultedinto a patterned master. Two systems to produce the polyelectrolyte multilayers (PEM)as the main body of the micro motors (plates) which’s diameter are5um、8um、10umwere used. The two methods to produce the plates are as follows:Method one: The patterned silicon substrate to produce patterned polydimethylsiloxane (PDMS) stamp (the stamp was produced by casting the liquid PDMS base andcuring agent mixture onto the silicon master and then curing it) which has themicropillars was assembled, and then the PEM on the surface of the PDMS stamp wasassembled with layer by layer method (LbL). When a micropillar stamp was used, thePEM on top of the micropillars was transferred on a glass slide coated with a thin filmof polyvinyl alcohol (PVA) or polystyrene (PS) by micro contact printing (μCP). Afterfinishing transferring the patterned PEM, the thin PVA or PS film was dissolved torelease the PEM plates into solution. This system was not found to be reliableMethod two: Making the thin PDMS thin film which’s thickness is around3mmand then assemble the PEM onto the surface of the PDMS film. The line tension andsurface energy of the polyelectrolyte multilayer depends on its composition (PAA, PAH,PDDA, PSS) film and therefore influences the interaction force between PEM, PDMSand the silicon substrate. The system was mathematically and experimentally optimizedfor the most suitable PEM system. Temperature, pressure and the time for printing withthe clean silicon master which has microwells were found to influence the system. Afterprinting, a lot of PEM plates on the PDMS film then with the same method as mentioned afore a sacrificial layer of PS or PVA was dissolved to release the PEMplates.In order to complete the functionalization of the PEM plates to make the plates runin the solution, method two was used. Platinum nanoparticles were used to catalyticallydecompose hydrogen peroxide. The platinum was added onto the PEM plates. One wayfor the addition of platinum is using the sputtering process in vacuum to deposit Pt ontothe surface of the PEM, then use warm water to dissolve PVA and release the plates.The second way is using ethanol to reduce chloroplatinic acid to systhesis Pt nanoparticles and then assemble these via electrostatic forces onto the PEM plates. Themechanism of the motor is the platinum catalytic decomposition of hydrogen peroxideto produce oxygen bubbles to drive the plates in solution. In this thesis the motor speedand trajectory in relationship between the oxygen bubbles and the motor movementdirection was analyzed.