Protective cotton fabric by coating of thermoplastic polyurethane combined with PDMS-TMS

Protective clothing has seen great potential in firefighting and military defence in which wearers are usually subject to harsh environment and threats. This study reports on the use of polyurethane coating as an alternative to perfluoroalkyl compounds which are deemed to be harmful for both human and environment. Cotton fabric was coated with polydimethylsiloxane-trimethylated silica (PDMS-TMS) by Pad-Knife-Pad coating followed by a curing under 150 oC for 3 min. The coated fabric showed superhydrophobic surface with a contact angle of 142 oC, and it exhibited resistance to oil, liquid and chemicals for long periods of time. The fastness of coating to washing and crocking was excellent, suggesting high stability and durability of the coating. Enhanced durability of the samples was achieved as a result of the recrystallization of the long chains of the methyl groups of the PDMS and Si-OCH3 bonding imparted between the substrate and the TPU coating. Superhydrophobicity and chemical and liquid protective properties of cotton fabric would benefit developing of protective clothing that deals with harsh environment such as firefighting and military gears.