Exploration of Stimuli-Responsive, Elastin-Based Coatings for Textiles

Abstract

Smart, stimuli-responsive materials that are also environmentally friendly are highly desired in the fashion and textile industry. For example, thermoresponsive properties show potential in creating dynamic comfort by improving moisture wicking and breathability at high temperatures. Additionally, color change properties provide aesthetic appeal and can be used as flexible sensors for physiological or environmental monitoring. Herein, the integration of bioproduced, thermoresponsive polymers into textiles as coatings that can also deliver pH-responsive color change is explored. Elastin-like polypeptides (ELPs) are recombinant protein biopolymers that exhibit an inverse phase transition when temperature is raised above a tunable transition temperature. To incorporate these into cotton textiles, amino acid residues with functional groups are genetically introduced. These are covalently coupled to oxidized cotton fabric, as well as a pH indicator dye, and copper-free “click” conjugation handles. Thus, a facile layer-by-layer assembly process is used to assemble coatings with tunable thickness. The chemical derivatization of ELPs is shown and how these modifications influence thermoresponsive properties in solution is demonstrated. Cotton fabric is oxidized to introduce carboxylic acid chemical handles and up to ten coats of ELP is layered onto the modified cotton. The coating demonstrates spatiotemporal pH responsive color change.