Fabrication Of Patterned Colloidal Polymer Particles And Its Carbonization

The patterned arrays of colloidal particles have received substantial attention becauseof their wide range of potential applications in photonic band gap materials, chemicaland biochemical sensing, data storage etc. However, it is still a grand challenge toconstruct complex, high-ordered structures by assembling and positioning theseparticles in desired locations. Currently, the prevalent approaches used to fabricatesurface patterns comprise template-assisted method, Langmuir-Blodgett transference,electrophoretic deposition, convective self-assembly, controlled evaporative self-assembly in a restricted geometry, and drying-mediated self-assembly. Herein, wepresent our experimental observations on the rearrangement of irregularly shaped,crosslinked poly(4-vinylbenzyl acetate)(PVBA) nanoparticles from an emulsifiedcolloid during evaporation. The main contents are as follows:(1) Synthesis of colloidal PVBA nanoparticles. The PVBA colloidal nanoparticleswere prepared by using a UV-initiated miniemulsion polymerization process. Theresulting polymeric nanoparticles with an irregular shape were used without furtherseparation and purification.(2) Fabrication of spoke patterns. We have successfully prepared spoke patternedfilms composed of PVBA particles arrays by the evaporation-driven self-assemblymethod and investigated the formation process systematically by varying severalexperimental parameters such as substrates and particle concentration. Scanningelectron microscope (SEM) and optical microscope are applied to characterize themorphologies of patterns.(3) The carbonization of spoke-like patterns of crosslinked polymer. We havesuccessfully prepared colloidal particles with different crosslinking degree andprepared spoke patterns with colloidal polymer suspension. The morphologies ofpatterns after carbonization were characterized by optical microscope and scanningelectron microscope (SEM).