Preparation of silver nanoparticles suitable for textile finishing processes to produce textiles with strong antibacterial properties against different bacteria types

摘要

This study describes the development of a preparation technique for silver nanoparticles useable as antimicrobial material which is especially useful for textile treatment to realize antimicrobial fabrics. The silver particles need to be prepared by reduction of AgNO_3 under moderate conditions and with a moderate and non-toxic reductive agent. Comparative investigations were carried out with silver particles prepared by a solvothermal process or with NaBH4 as reductive agent. Particularly, suitable silver solutions are obtained by stabilizing the silver particles with polyvinylpyrollidone PVP of high molecular weight (M_w ～ 360000 g mol~(-1)) and the use of the non-toxic reductive agents ascorbic acid and fructose. Under these conditions the diameters of the silver particles are in the range of 10 to 30 nm as determined by HR-TEM. The formation of elemental silver has been verified by transmission electron microscopy (TEM), X-ray diffraction (XRD) and optical spectroscopy. The properties of silver particle-containing liquids were investigated by using UV/Vis spectroscopy and dynamic light scattering. Further information on particle size and size distribution was gained through SEM investigations. The prepared solutions of silver nanoparticles can be applied easily onto textiles as liquid coating agents. All prepared textile samples exhibited a high antimicrobial activity against Escherichia coli. However, only few solutions containing silver particles of smaller size exhibit high antimicrobial activity also against other types of bacteria such as Staphylococcus aureus and Streptococcus pneumoniae. Because of this high antimicrobial potential gained with silver solutions prepared in a simple process without usage of toxic components, the developed materials offer a broad range of potential applications.