Antimicrobial coatings on textiles–modification of sol–gel layers with organic and inorganic biocides

Antimicrobial textile materials were produced by sol–gel coatings with embedded biocidal compounds. For preparation a sol–gel procedure was used, starting from pure silica sols and 3-glycidyloxypropyltriethoxysilane (GLYEO) containing silica sols. These sols were modified with silver compounds, hexadecyltrimethyl-ammonium-p-toluolsulfonat (HTAT) and copper compounds, respectively. The investigations were performed on viscose fabrics as function of the concentration of biocidal compounds and of thermal treatment of textile after dip-coating between 80 up to 180 °C. The use of modified silica coatings leads to a decreased growth of fungi (Aspergillus niger) and bacteria (Bacillus subtilis and Pseudomonas putida) with increasing amount of the biocide embedded in the coating. The addition of GLYEO supports the biocidal effect of the coatings and enhances the stability of the coating solutions. For preparation of antimicrobial silica coatings the biocides silver, copper or HTAT can be used alone but the combination of these compounds leads to enhanced results against both fungi and bacteria. Therefore silica sols containing a combination of different types of biocides may be used for antimicrobial modification of textiles in some practical applications. For industrial applications the here presented coating solutions are especially advantageous, because of 90% water content in the solvent.