Construction Of Conducting Polymer Patterns Based On The Nanoimprint Lithography

In the past decades, conducting polymer patterns have been employed in many different kinds of devices, such as field-effect transistors (FETs), light emitting diodes, integrated circuits, and sensors. And the patterns with the feature sizes of sub-micrometer to nanometer have recently received much attention because of their unique properties. To fabricate the conducting polymer patterns, various approaches, including photochemical patterning, microcontact printing (μCP), scanning probe lithography (SPL), electron-beam lithography (EBL), and many other methods have been proposed. However, scientists are still searching for the cost-efficient method for patterning conducing polymers with high resolution on large area.For its relative low cost, high throughput, high reproducibility, and enviable resolution of a few nanometers over large area, nanoimprint lithography has been used for pixeled color structures, light emitting devices, electronic device and other devices. Comparing with the aforementioned methods, nanoimprint lithography has made a large progress in patterning. However, the cost and the lifetime of the stamp are still restricting the spread of the technique, which requires a good many efforts.In this thesis, we aimed on the development of the conducting polymer patterning methods which are both simple and cost-effective. The works accomplished are listed as follows:Firstly, the nanoimprint course was studies in detail. Although there have been a lot of papers focused on the nanoimprint course, no one have been exactly discussed the course when the stamp is with large cavity and small depth, while the resist polymer is relatively thin. Based on the phenomena we found, the inadequate imprinting course was well discussed. And the high resolution patterns were fabricated by low resolution stamp.Secondly, by the combination of inadequate imprinting and the isotropic etching, high resolution conducting polymer patterns were fabricated by low resolution stamps. The resolution of the conducting polymer patterns are exactly controllable by designing the imprinting and etching course. Moreover, the property of the conducting polymer pattern was well kept, with a most improvement on the resolution of ten times. A cost-effective imprinting method was proposed.Thirdly, to exploit the usage of the conducting polymer patterns on the biosensors, by using the polyaniline pattern as the templete and controlling the deposition condition, the Silver nanoparticles were selectively adsorbed on the polyanilane patterns by the electrostatic interaction, and the combined patterns with high resolution were constructed.Fourthly, based on the PS colloid sphere self-assembling technique, we fabricated polymer stamps which are suitable for hot embossing nanoimprint. It is worthy to mention that both the stamps with positive and negative patterns were fabricated by one stamp fabrication course. PMMA patterns with different periodicity were fabricated by the utilization of PS colloid spheres with different diameters. And by using conducting polymer deposition, polyanilane dot arrays with different periodicity were constructed. Further more, modulating the PMMA pattern etching duration, the diameter of the polyanilane dot was controlled. Moreover, polyanilane network patterns were fabricated by the negative patterned stamp.In conclusion, two smart large area conducting polymer patterning methods were introduced in this thesis. Avoiding the high cost of the stamp fabrication, new cost-effective strategies were illustrated for the fabrication of conducting polymer patterns over large area.