(601c) Development of a Rechargeable Antimicrobial Textile Utilizing Radical Click Chemistry and Reactive Dyeing Techniques

Due to the moisture and heat provided by proximity to the human body, textiles serve as ideal habitats for microbes. Therefore, fabrics with the ability to self-disinfect have promising medical and military applications along with numerous commercial niches. Of the currently studied antibacterial agents, n-halamines are of particular interest due to their rechargeable nature and contact-killing efficacy. These biocides are created by the preferential uptake of cationic chlorine, usually sourced from hypochlorite/hypochlorous acid solutions, by certain amines, amides, and imides. When incorporated into materials, these compounds imbue a powerful contact-killing effect via the slow release of said chlorine. While this action does result in the re-conversion of halamine to amine, the process is amiably reversed by exposing the depleted compound to a similar chlorine source.

In developing a process for rending cotton with the properties of n-halamines, the most direct approach is covalent modification of the cellulose backbone. This strategy has been long-explored and is the basis of the reactive dyeing process which is used to impart color to textiles. Taking motifs from reactive dye chemistry, we designed a compound which employs cyanuric chloride as a binding agent. Cysteine serves as the link between this binder and the intended n-halamine which is built off 5,5-dimethylhydantoin. Our group had previously produced this molecule via an in-situ method, building directly off the textile surface, to investigate the retention of antibacterial effect after chemical grafting. Following success with the aforementioned approach, the subsequent goal was to create the agent as a standalone compound which can be applied to fabric in a single reaction. The devised synthesis strategy results in a chemical analogous to a dichlorotriazine (DCT) dye with suitable water solubility and reactivity for industrial textile manufacturing.

Said compound’s structure is validated by FT-IR and NMR. Herein, the treated fabric is explored via FT-IR surface characterization to validate synthesis and ensure attachment. The effective chlorine loading of the treated fabric is determined through iodometry. This technique is also used to determine cycle rechargeability and storage stability. A novel qualitative antibacterial assay was designed to track contact-killing efficacy. In addition, a minimum inhibitory concentration study is performed to ratify the biocidal nature of all reagents used.