PHYS01200704032 Debes Ray - Homi Bhabha National Institute

Chapter 2: Block Copolymer-mediated Synthesis of Gold Nanoparticles
films using block copolymers has been achieved via selective solvent evaporation, which
leads to cooperative self-assembly of the block copolymer and silicate to produce
mesoporous silica with hexagonally arranged pores, vesicular structures or rods [135,136].
(v) Nanoreactors: Block copolymer domains can be used as nanoreactors for the synthesis
of inorganic nanoparticles [133,137]. Two basic approaches have been developed. The first
one involves the binding of inorganic species to the monomer prior to polymerization or to
one of the blocks of a copolymer prior to micellization (which may be induced by the ion
binding). The most important approach, however, involves the loading in the preformed
micelles, whether in solution or in bulk [138].
2.3. Synthesis of Gold Nanoparticles by Block Copolymers
The preparation of metal nanoparticles in solution is most commonly based on the chemical
reduction of metal ions and invariably involves organic solvents and ligands [137,139-144].
The utilization of nontoxic chemicals, environmentally benign solvents and renewable
materials are emerging issues that merit important consideration in the development of
synthetic strategies. A methodology based on the use of water as the solvent provides an
environmentally benign route to the production of gold nanoparticles and result in a product
that can be easily integrated in applications involving aqueous media [139-144]. It has been
recently shown that gold nanoparticles can be synthesized from HAuCl 4 .3H 2 O using Pluronic
block copolymers, without additional reducing agents and external energy. Block copolymers
not only act as a reducing agent but also enhance the nucleation and growth of nanoparticles
as well as provide stability to the nanoparticles [94-98,145].
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