Functionalization of Cotton by Thermoresponsive Polymer Brushes for Potential Use as Smart Dressings

Cotton is the most widely used dressing material due to its universal availability, affordability, high biodegradability, and ease of recyclability. Modern and advanced techniques for controlled polymer grafting onto its surface enhance and precisely tailor cotton's properties. These improvements contribute to the healing process by preventing adhesion to wounds, facilitating the absorption of body fluids, and enabling the design of innovative dressings capable of the controlled release of active substances. Therefore, this study presents the grafting of thermoresponsive polymer brushes composed of di(ethylene glycol) methyl ether methacrylate (DEGMA) and poly(ethylene glycol) methyl ether methacrylate (OEGMA, M ∼ 500) onto a cotton surface using surface-initiated supplemental activator and reducing agent atom transfer radical polymerization (SI-SARA ATRP). By precisely adjusting the composition of DEGMA and OEGMA₅₀₀, we achieved precise control over the polymer layer's lower critical solution temperature (LCST) behavior. The LCST of the copolymers formed in the reaction mixture in the presence of the functionalized surface was analyzed via transmittance measurements. Furthermore, the thermoresponsive properties of the polymer layer grafted onto the cotton surface were evaluated through water contact angle (WCA) measurements at varying temperatures. In addition, the temperature-dependent protein adsorption of the polymer-functionalized cotton was examined to assess the potential dressing's adherence to wounds. Finally, the resulting materials were tested for residual copper content and cytotoxicity.