The Preparation And Application Of Environment-Sensitive Hairy Monodisperse Polymer Particles

The Uniform hairy micron-size polystyrene(PS) particles attached with environment-sensitive brushes were prepared by Reversible Addition-Fragmentation Transfer (RAFT) technology with three steps. Firstly, the monodisperse PS particles were prepared by emulsifer-free emulsion polymerization. Secondly, the RAFT agent or photo-initiator were anchored on the surface of the above PS particles using "starve" addition with and without styrene. Finally, functional monomers were added and temperature-responsive and pH-resposive brushes were obtained by UV light-initiated surface polymerization. Furthermore, large scale three-Dimenional(3D) regular colloidal crystals film was prepared to investigate the influence of the temperature-responsive brushes to the morphology of formed film.The preparation of brushes by RAFT technology was achieved by RAFT agent anchored on the surface via Z-group or adding free RAFT agent as the media. Synthesis and comparison of homopolymer brushes bewteen RAFT polymerization and conventional free radical polymerization were discussed, including the change of brush thickness, monomer conversion, partition coefficient, brush yield and molecular weight. All the results showed the characteristics of live/controlled radical polymerization using RAFT technology. In addition, block brushes were synthesized and studied.The preparation of 3-D colloidal crystal films by the PS particles with temperature-responsive PNIPA brushes was discussed. By changing the conditions such as the diameter of PS particles, the thickness of PNIPA brushes, and the temperature, etc. the optics properties of this 3-D structural film were studied. Besides, in order to investigate the RAFT technique in the fields of linearly controlled polymer brushes growth and the colloidal crystal film, comparisons between the traditional polymerization and Z group of the RAFT agent attachment were discussed. SEM characterized the 3-D structures and the arrangements of the particles, and UV-near infrared spectrum indicated the optics properties.