Microcontact Printing Induced Supramolecular Self-assembly For Patterned Polymeric Surface And Its Application Research

Functional polymers with patterned surfaces have attracted tremendous interest because of the abundant functionalities of polymers and a wide range of applications including cell biology, tissue engineering, medical science, optics and electronics. Fabricating patterned polymer surfaces with complex microstructure is in great request. Supramolecular self-assembly is demonstrated as an aggregation of molecules driven by hydrogen bond, electrostatic interaction, etc. In this thesis, patterned polymer surface with various complex morphologies were fabricated by one-step microcontact printing(μCP) induced supramolecular self-assembly. Self-initiated photo grafting and photopolymerizaion(SIPGP) becomes a facile and highly efficient method due to the absence of surface-bonded initiator and any photo sensitizer. By combination of supramolecular self-assembly and SIPGP, we demonstrated that a commercial polymer of polyethyleneimine(PEI) with rich amino groups can be used as a versatile “ink” for the direct fabrication of patterned PEI surfaces via a supramolecular interaction between amino groups in PEI and –OH on a silicon wafer induced by μCP, and that the obtained patterned polymeric surfaces could be amplified further to grow other polymer brushes. Moreover, the patterned PEI surfaces can also be explored as novel surface-enhanced Raman scattering(SERS) active materials by electrostatic adsorption with negatively-charged gold nanoparticles(Au NPs). We obtained some new results in following aspects: 1. Construction of pattterned catonic polymer surface by microcontact printingPatterned polymer surface with various complex morphologies were fabricated by one-step microcontact printing(μCP) induced supramolecular self-assembly. The thickness, size and morphology of PEI patterns can be controlled by varying reaction condition. Importantly, new microstructures that not exsit on the original stamp can be obtained. 2. Functionalization of patterned polymer surfacePatterned PEI-g-PS polymer brush was obtained by SIPGP due to the high photoactivity of amino groups in PEI molecular. The thickness of patterned PEI-g-PS polymer brush can be controlled by varying the thickness of patterned PEI surface before SIPGP. Au NPs with negative charge can self-assemble on patterned PEI surface with positive charge by electrostatic adsorption to fabricate patterned Au NPs surface. The patterned Au surface can be used in SERS which significantly enhanced the Raman signal of R6 G.