The Application Of Soft Lithography In Polymer Science

P7olymer is the perfect micro/nano-meter architecture material because of the peculiar macromolecule chain structure,chemical and physical characteristic. Polymeric microstructures have special functions and had applications in the fields such as chemistry, biology, communication, and physics. Soft lithography (SL) is one low-cost and high-precision microfabrication technology, it can effectively fabricate abundant microstructures of many kinds of materials without costly equipments and rigorous environment. SL has a wonderful applied foreground.In this Ph.D. dissertation, author introduced SL technology into polymer science and fabricated polymeric microstructures via SL technology, these microstructures had been of value of scientific research or applications, the obtained results are summarized as following:1. Micromolding in Capillaries by Swollen Elastomeric StampThe PDMS elastomeric stamp can be swelled by some organic solvent, the swollen PDMS stamp induce the distortion of microstructure, which is one of disadvantages of SL. We changed this disadvantage into one new advantage and obtained polymethylmethacrylate (PMMA) microstructure via micromolding in capillaries by the swollen PDMS elastomeric stamp (MIMICSES). In MIMICSES, the polymeric microstructure can be controlled by changing the amount of polymer solution and the external pressure. MIMICSES extends the variety of materials patterned via SL, and offers us a new microfabrication technique of polymer.2. Micro-lens Array of Polymer Fabricated via Micro-molding and HeatingMicro-lens and micro-lens array are important optical components widely usedin many fields. Taking advantage of the principle of liquid or melting matters will be the most stable state by means of reducing its surface energy to minimum, the micro-hemispheroid arrays of PMMA and polystyrene (PS) were successfully obtained via micro-molding of SL and heating technology . The optical imaging testing indicated that these micro-hemispheroid arrays had good optical behavior and could be used as micro-lens arrays. This micro-molding & heating technology is easy and low-cost with high precision and can be suitable for other transparent plastics, it offers us a new microfabrication technique of polymer micro-lens array.3. Polymer Microstructures Array Fabricated via Micro-Contact Printing (μCP) TechniqueUsing octadecyltrichlorosilane (OTS) as "ink", Micro-reactions array was fabricated viaμCP on hydrophilic silica, then the array was immerged into the reaction system making up of methylmethacrylate (MMA) & benzonphenone(BP) , and then polymerized by UV. PMMA microstructures array was obtained. Research results indicated that the micro-polymerization occurred in the hydrophobic OTS micro-area, which tallied hydrophobia characteristic of the reaction system. PMMA particles of microstructure array depended on the ratio MMA to BP. Micro-reactions array offers us an new polymer micro/nano- patterning technology which fabricates polymer micro/nano- particles array with monomer, and it also offers us an new method fabricating polymer micro/nano- particles with different crystals.4. Fabrication of the Micro-mold of Macromolecule Chain(1) Single linear PS microspheres chain was successfully obtained respectively via MIMIC technology and magnetic field self-assembly technology. We investigated respectively the mechanisms and condition of PS microspheres arranging into linear PS microspheres chain and the controllability of linear PS microspheres chain, and found that magnetic field self-assembly technology is better simple and effective.(2) The neighboring PS microspheres of linear microspheres chain were linked respectively by heating and polyvinylpyrrolidone (PVP) linker. The linear PS microspheres chain linked by heating was most brittle and ruptured under slight outside force, and didn't curve; we named it "rigid macromolecule chain". The linear PS microspheres chain linked by PVP was stable with some degree of flexibility; we named it "soft macromolecule chain" and looked it as the micro-mold of real macromolecule chain to simulate the condensed state of polymers in mesoscopic scale.5. Simulating. the Condensed Process of Macromolecule Chain in Mesoscopic Scale Looking the linear PS microspheres chain linked by PVP as the micro-mold of real macromolecule chain, we simulated respectively the condensing process of macromolecule chain with different configuration in mesoscopic scale by solvent-volatilizing, and observed the condensing action and condensed state of "soft macromolecule chain" at different conditions. The experiment results tallied the existing theories at certain degree. We hope that this work could offer one new method for the study of the condensed state physics of polymers.