A Smart Cotton Fabric With Temperature Sensitive Moisture Management Property By An N-Vinylcaprolactam Based Polymer Finishing

In this study, it was aimed to develop a smart cotton fabric with temperature-sensitive wetting and water vapor permeability management functions. For this purpose, n-vinyl caprolactam (VCL) based poly(2-hydroxyethyl-6-(vinyl amino)hexanoate) (PHEVAH) polymer was synthesized by free radical addition polymerization method. The produced polymer was cross-linked onto the cotton fabrics using 1,2,3,4-butanetetracarboxylic acid. Before the synthesis, VCL was hydrolyzed with ethylene glycol in toluene to open its ring structure and obtain a new monomer with different functional group and molecular weight. The synthesis of the PHEVAH polymer with average molecular weight of 4000 g/mole was confirmed by 1 H-NMR spectroscopy. Its lowest critical solution temperature (LCST) was determined at around 34°C. The surface morphology of the fabrics coated by the polymer were confirmed 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. Their surface contact angles increased and water uptake values decreased. The vapor permeability of the fabrics treated with low concentration polymer was significantly high as compared to untreated fabric. Consequently, the fabrics was able to control water vapor permeability by changing their temperature-dependent hydrophilic/hydrophobic character and 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.