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Advances in Nanofibre Research Volume 3
nanotechnology application for textiles is currently in the area of antibacterial coating.
Antibacterial coatings are applied to textiles for four major reasons: (a) to control
the spread of disease and the danger of infection following injury; (b) to control
infestation by microbes; (c) to control the development of odour from perspiration,
stains, and other soiling on textile materials; and (d) to control the deterioration of
textiles, especially fabrics made from natural fibres, caused by mildew [1-10].
Recently, new techniques for the modification of textile fibres using antibacterial
nanosized silver particles have been introduced by researchers.
The most popular methods of synthesizing silver nanoparticles, the antibacterial
properties of silver nanoparticles, their interactions with microorganisms, and
assessment of antibacterial activity are the most important issues which will be
discussed here.
1.2 Background
Several synthesising procedures were reported for the preparation of silver
nanoparticles in the literature and most of them were based on chemical reduction,
the Tollens process, UV light reduction, UV light and chemical reduction concurrently,
and biological processes. Among these methods, the chemical reduction methods have
been widely studied, due to the fact that they are effective, economic and convenient.
For chemical reduction methods, the choice of the reducing agent is, of course, the
major factor; gamma-radiation, hydrazine, sodium borohydride, sodium citrate,
potassium bitartarate, dimethylformamide, ascorbic acid, and alcohols are some of the
reducing agents that have been successfully used. The reducing ability will determine
the formation kinetics and hence the reaction temperature. The reaction can be carried
out in either aqueous solution or in an organic solvent such as in the polyol process.
All these methods involve the reduction of relevant metal salts, usually silver nitrate
(AgNO
3
)
or silver acetate, in the presence of a suitable protecting agent, which is
necessary to control the growth of metal colloids through agglomeration. Long-chain
n-alkanethiols are the most common protective agents employed to stabilise silver
colloids, but aromatic amines such as aniline, carboxylic acids, and polymers have
also been used. However, these methods can lead to significantly different results in
terms of size and morphology, depending not only on the choice of the reducing agent
and stabiliser but also on the reaction conditions [11-20].