Omniphobic polyurethane – superabsorbent polymer – fluoropolymer surface coating on cotton fabric for chemical protection and thermal comfort

Abstract

This research aims to develop chemical protective clothing via a functionalised surface coating on cotton fabric for simultaneous barrier performance and thermal comfort. An omniphobic protective layer on the cotton fabric was developed through a polyurethane – superabsorbent polymer – fluoropolymer coating to protect the penetration of water, oils and liquid chemicals. It was found that the padding of coated specimens with fluoropolymer provided a substantial improvement of hydrophobicity, and therefore, exhibited a high-water contact angle (114.06°) and a maximum water repellency rating of 100. The highest aqueous liquid repellency (8.0) and satisfactory oil repellency (7.5) with resistance against liquid chemical penetration were also achieved after the treatment with fluoropolymer. Moreover, the coated fabrics integrated with superabsorbent polymer showed an improved dry heat resistance and moisture vapour transmittance, consequently a high evaporative cooling index to create a favourable thermal comfort between the skin and the apparel in hot and humid conditions. Other comfort parameters, including air permeability and moisture management performance were compromised to a certain level due to a continuous and hydrophobic barrier layer on the fabric surface that hindered the transferring of air and liquid sweat through the coating.