Water-soluble Polymer Brushes As Templates For The Preparation Of Silver Nanoclusters/Nanoparticles

In this dissertation, water-soluble polymer brushes with Polyacrylate backbone and polyacrylate acid side chains was sucessfully fabricated, via the combination of atom transfer radical polymerization (ATRP) and "click chemistry" which is widely used at present. Both the backbone and the side chains are derived from poly(tert-butyl acrylate). After hydrolysis of ester group in polymer brush side chains in acidic conditions, carboxyl functional groups can be essily attained, which have strong coordination ability with silver. So we have prepared morphologically controllable and small size silver nanoparticles using the polymer brushes with many uncovered carboxyl functional groups as templates, and also studied the changes in morphologes, and ultraviolent and fluorescence optical properties by changing the molecular weight of primary and branched-chainsof the polymer brush or by using different reductant. The specific contents of this dissertation are described as follows.1. Poly(tert-butyl acrylate) (PtBA) with very narrow distribution of molecular weight and PtBA different molecular weight were gained by the method of ATRP. The as-prepared polymers were characterized by gel permeation chromatography (GPC) and the results show that the polydispersity index (PDI) is between 1.05-1.10.2. After chemical modification of PtBA, backbones terminated with alkynyl and side chains end-capped with azido can be obtained. Their molecular structures and physical properties were characterized in detail by FT-IR,1H NMR, and GPC.3. Polymer brush was synthesized from the coupling crosslink reaction of backbones with alkynyl side groups and side chains end-capped with azido via "click chemistry". When the ester group was hydrolyzed in acidic conditions, the water-soluble ability of the polymer brush is very well, and it can be improved obviously as the molecular weights of side-chains increase. Moerover, the polymer brushes become water-soluble in a wider range of pH. 4. Silver nanoparticles were prepared using different reduction processes and polymer brushes with different molecular weights as templates. It turns out there are some distinctions betweens the sizes and morphology of nanoparticles has some distinction when the same template but different reduction method was used. Variations almost can not be observed when the same reduction method but different templates were employed.5. When the reduction process of UV-irradiation at= 365nm was carried out, light blue fluorescent silver nanoparticles were obtained. The fluorescence intensity will generally decreace as the irradiation time expanded.