Seeking the lowest phase transition temperature in a cellulosic system for textile applications

Abstract

Smart or intelligent polymeric materials respond to small changes in their environment with a considerable change in their physicochemical properties. Environmentally responsive hydrogels have the capability to turn from solution to gel, when a specific stimulus like temperature, pH, chemicals, ultrasounds, light, electric fields and mechanical stress, is applied. Cellulose esters thermoreversible hydrogels, like HPMC, MC and NaCMC, are very appealing once they are naturally derived from cellulose, which is the most abundant naturally occurring biopolymer on earth. Allied to this advantage it is also associated the non-toxicity, biocompatibility, biodegradability and eco-friendly properties. The transition temperature of the abovementioned cellulose derivatives is medium/high (82.5, 67.5 and 47.5 degrees C) that is considerable elevated for most biochemical and textile applications. Therefore, within this research it is reported a systematic study to depress the gelation temperature of the cellulosic NaCMC. Several factors may influence sol-gel transition temperature of this cellulosic but herein the focus stood on the influence of polymer concentration, of admixing inorganic salts (NaCl and enriched salt solutions), polyols (glycerol) and polyols salts (Na/CaGlyPhos) and lastly the interaction with polyelectrolytes (CH-NaGlyPhos). The aforementioned modifications were afterward registered by UV-Vis spectroscopy. For the developed stimuli sensitive hydrogels it is envisioned the application on the textile materials, more specifically in the delivery of active species (e.g., scents, moisturizers, antiperspirants)/perspiration absorption, through textile apparel. The system will be triggered by human body temperature and thus a thermogelation temperature of 28-35 degrees C (skin-cloths microclimate temperature) is compulsory.