Effect of the Chain Density and Chain Length on the pH-Responsibility of Poly(acrylic acid) Grafted Cotton

With the development of material science, pH-responsive fabric emerges as a novel material in recent years. Effect of chain density and chain length on the conformation transition of surfaceanchored polymers is a fundamental problem which relates to their functionality. In this work, poly(acrylic acid) (PAA) was grafted onto cotton fabrics through surface-initiated atom transfer radical polymerization (ATRP) technique. The chain length of PAA was modulated by monomer concentration, and the grafting density was regulated by the density of amino groups on the fabric surface. Contact angle analysis, IR measurement and water uptake observation were employed to study the pH-responsive behavior of the PAA modified cotton. Fabrics with polymers of a larger molecular weight and optimal grafting density exhibited better pH-responsibility. This study provided a structure-property fundamental understanding on the important parameters influencing the pH-responsibility of PAA modified cotton fabric.