Fabrication Of Organic/Inorganic Hybrid Composites By Surface-Initiated Atom Transfer Radical Polymerization

In recent years, organic/inorganic nanocomposites have attracted more and more attention and become one of the focuses in the area of materials due to their excellent properties. As one of its branches, inorganic nanoparticles/polymer composite films and shells possess the potential applications in modifying surface properties. The way to control the diameter, the content and the distribution of nanoparticles in polymer plays a significant role in the development of the fabrication of functional inorganic/organic nanocomposites. ATRP which is a novel technique allows better control the molecular weight and molecular weight distribution of the target grafted polymers. Using ATRP method many kinds of well-defined polymers such as block, star, graft, hyper branched (multifunctional) copolymers, inorganic/organic hybrid materials and nonmaterial etc. can be conveniently synthesized just because of its merits to control the structure of polymeric materials.This paper mainly includes three parts. Firstly, well-defined polystyrene brushes on palygorskite using bromo-acetamide as macroinitiators and 2, 2'-bipyridine (bpy) and Cu(I)Br as catalyst are synthesized by surface initiated atom transfer radical polymerization (ATRP). Secondly, polystyrene (PS)-grafted palygorskite (PG) nanoparticles are prepared by a"grafting onto"strategy based on reverse atom transfer radical polymerization (RATRP) using CuCl2 as a catalyst and 2,2'-bipyridine (bipy) as a ligand at a mild temperature. Palygorskite particles were at first surface modified by vinyl trimethoxysilane (A-171) and then polystyrene chains were grated. And thirdly, polystyrene films were successfully prepared on glass substrate by surface-initiated reverse atom transfer radical polymerization (reverse SI-ATRP) where peroxide groups as the initiator were first grafted onto glass surface, and then polystyene brushes are synthesized by reverse ATRP using CuCl2/2, 2′-bypyridine as catalyst and ligand. Analysis of the polymer films were carried out using X-ray photoelectron spectroscopy, contact angle measurements, ellipsometry, atomic force microscopy and gel permeation chromatography respectively. The resultr have indicated that polystyene is successfully grafted on glass surface and kinetic studies reveals linear increase in polymer film thickness and ln([M]0 /[M]) with reaction time, the molecular weight of the grafted polymer can be controlled with a"living"characteristic.