A smart cotton fabric with adaptive moisture management through temperature sensitive poly(2-hydroxyethyl-6-(vinyl amino)hexanoate) finishing

This study aimed to develop a smart cotton fabric with wetting and water vapor permeability properties stimulated by a certain temperature. N-vinyl caprolactam (VCL) based poly(2-hydroxyethyl-6-(vinyl amino)hexanoate) (PHEVAH) polymer was evaluated as a potential polymer to bear this desired properties and synthesized by free radical addition polymerization. HEVAH monomer was produced by hydrolyzing VCL with ethylene glycol in toluene to open its ring structure and obtain a new monomer with a different functional group. The produced polymer was grafted to a cotton fabric using 1,2,3,4-butanetetracarboxylic acid. The synthesis of the PHEVAH polymer with average molecular weight of 4000 g/mole was confirmed by (1) H-NMR spectroscopy. The lowest critical solution temperature (LCST) was found to be about 34 C, which is slightly higher than its equivalents in the literature. The surface morphology of the fabrics coated by the polymer was investigated by SEM images. The temperature-sensitive hydrophilicity and wettability of the fabrics were determined by wetting time and water uptake tests, and contact angle measurements. At temperatures above the LCST of the polymer, the hydrophilic character of the fabrics turned to hydrophobic and therefore surface contact angles increased and water uptake values decreased. The vapor permeability of the fabrics treated with polymer solution at low concentration was significantly higher than that of the untreated fabric. Consequently, the fabrics were able to control water vapor permeability upon temperature stimulated hydrophilic to hydrophobic character and therefore porosity resulting from swelling or shrinkage of the polymer molecules. Besides, PHEVAH polymer formed a flexible coating on the fabric surface and did not increase the bending rigidity of the fabrics.

Automated summary

This study developed a smart cotton fabric with wetting and water vapor permeability properties stimulated by temperature. N-vinyl caprolactam based PHEVAH polymer was synthesized by free radical addition polymerization and grafted onto a cotton fabric. The synthesized polymer showed a low critical solution temperature of 34°C. The fabrics treated with the polymer exhibited a temperature-sensitive hydrophilic to hydrophobic transition and increased vapor permeability. The PHEVAH polymer formed a flexible coating on the fabric surface without increasing its bending rigidity.