Authors: J.H. Johnston, F.M. Kelly
Affilation: Victoria University of Wellington, New Zealand
Pages: 255 - 258
Keywords: nanoparticle, silver chloride, wool, composite, anti-microbial, colour
The development and characterisation of a new nanowool hybrid material formed by functionalising merino wool with silver chloride nanoparticles is presented. The nanoparticles are formed directly on the surface and inside the wool fibre. Initially there is no change in the colour of the nanowool hybrid material. However upon exposure to ambient light, the fibres develop strong and attractive colours ranging from shades of pink through to purple, depending upon the nature, composition and size of the silver chloride nanocrystals in the wool. The wool acts as a solid state matrix restricting diffusion of the silver and chloride ions thereby influencing the size of the nanocrystals. The colour which develops upon exposure to light is due to the photo-reduction of some silver ions to silver atoms in the silver chloride matrix forming colour centres in the lattice. This is shown by synchrotron XRD measurements where the appearance of silver peaks was coupled with the simultaneous decrease in silver chloride peaks. SEM, TEM and XPS measurements show that the silver chloride nanoparticles are chemically bound to the sulfur entities on surface and within the fibres. The hybrid materials also exhibit strong and effective anti-microbial properties due the nano silver chloride entities.