Adjustable thermal barrier of cotton fabric by multilayer immobilization of PCM nanocapsules

Abstract

Poly(diallyldimethylammonium chloride) encapsulated n-octadecane nanocapsules (Cap+) were facilely immobilized on cationized cotton at ambient temperature by stepwise coating with poly-4-styrenesulfonic acid (PSS) binder and Cap+ nanocapsules via layer-by-layer technique. The negative molecules of PSS binder spontaneously attached on the cationized cotton and then acted as negative sites for further immobilization of positively charged Cap+ nanocapsules through electrostatic interaction. The increase of quantity of immobilized Cap+ nanocapsules could be obtained by increasing the number of PSS/Cap+ treatment cycles. The prolonged duration of thermoregulating action was obtained when increasing the quantity of Cap+ immobilized on the cotton fabric, resulting in the adjustable thermal barrier property of cotton fabric. The cotton sample immobilized with 5 cycles of PSS/Cap+ treatment exhibited the highest reduction of surface temperature, i.e. ~ 2.5 °C for longer than 10 min when the surrounding temperature was about 50 °C. In addition, this sample could retain about 77% of original quantity of immobilized Cap+ after 15 washing cycles. The facile polyelectrolyte assisted nanoencapsulation and immobilization of PCM nanocapsules on the cotton fabrics proposed in this study were effectively performed using low concentrations of non-toxic chemicals, in which they might be incorporated into the conventional fabric finishing system.