Hydrophobicity and antibacterial property of silica sol-chitosan-HDTMS treated silk fabric

The present work aims to develop a hydrophobic surface with anti-bacterial capability on silk fabric with the help of silica sol gel, chitosan and hydrolysed hexadecyltrimethoxysilane (HDTMS) and to study the durability of coating in aqueous media (pH 7.4). Silica sol is produced by hydrolysing and condensing of tetraethoxysilane under alkaline conditions and then applied on silk fabric. This is followed by hydrophobization on the silica sol-treated surface of the fabric by applying hydrolysed HDTMS. Further, chitosan is applied on the silica sol-coated surface prior to HDTMS hydrophobization for its antibacterial property. The fabric is immersed in aqueous medium for 30 days to test the stability of the coating. The hydrophobicity of the fabric has been assessed by measuring the water contact angle and the antibacterial property is measured by using the AATCC-147 test protocol. The developed fabric exhibits antibacterial and hydrophobic properties. It is observed that there is a change in contact angle from 152.7° to 90.18° after 30 days of wetting and an increase in anti-bacterial activity, i.e. the zone of inhibition from 1 mm to 5 mm. The wicking properties of treated and untreated fabrics are measured to observe the impact of coating on wicking. SEM analysis has been carried out to determine the change in surface morphology of the fabric, and FTIR is used to determine the changes in the surface functional groups after coating and after wetting of coated fabric for 30 days in aqueous media. Such hydrophobic silk fabric with an antibacterial property may be useful for the development of natural biomaterial and other technical textile products.