(624d) Functionalization of Cellulose Surfaces Using Dye Anchors and Click Chemistry

Chemical modification of fabrics is an area of interest offering both functional consumer products and novel industrial applications. This work focuses on the chemistry and kinetics of covalent attachment of functional groups to cellulose fabrics, in particular functional groups that impart super-hydrophobicity to cotton fibers. The method employs cyanuric chloride (2,4,6-trichloro-1,3,5-triazine), which has been used for several decades as an anchor for attachment of dyes to the fabric surfaces. The action of cyanuric chloride on the surface of cellulose fabric allows for facile, high-yield attachments of compounds by nucleophilic substitution with amines. Attaching cysteamine to the cyanuric chloride anchor leaves a terminal thiol to which a range of compounds can be attached via thiol-ene click chemistry with alkene reagents and thermal radical initiators. Using them, we create a superhydrophobic surface, or one having a contact angle with water greater than 150°. Notably, this process yields a superhydrophobic textile without the incorporation of perfluorocarbons, whose precursors are hazardous and environmentally pervasive. In addition to the hydrophobic functionalization, other compounds have been attached, including compounds that functionalize the fabric to exhibit acidic and basic properties. The examined reactions result in high yield of thermally and chemically stable products. The novel chemistry provides a straightforward means to modify fabrics using inexpensive starting materials. The effects of process variables including temperature and concentrations on the resulting surface coverage and fabric properties will be discussed. These syntheses offer versatile, efficient, and scalable methods for permanent attachment of a variety of functional groups to fabrics and other cellulosic materials.