Laccase-catalyzed polymerization of diaminobenzenesulfonic acid for pH-responsive color-changing and conductive wool fabrics

Abstract

In recent years, there has been extensive interest in the research of smart fabrics and functional textiles. The present work has successfully developed the enzymatic approach for dyed wool fabrics in possession of special pH-responsive color-changing and conductive properties, via in-situ polymerization of 2,5-diaminobenzenesulfonic acid (DABSA) by laccase from Trametes versicolor. The enzymatically synthesized product, poly(2,5-diaminobenzenesulfonic acid) (PDABSA), was characterized by Fourier transform infrared spectroscopy, ultraviolet-visible (UV-Vis) spectrophotometry and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The redox property and thermal stability of the polymer products were studied by cyclic voltammetry and thermogravimetric analysis, respectively. The results proved that the resulting polymer reached 2 KDa and showed strong pH-dependence of UV-Vis absorption, electrochemical activity and high thermal stability. Utilizing the doping/dedoping process of PDABSA, the dyed wool fabrics were endowed with a pH-dependent redox potential. Furthermore, the dyed wool fabrics exhibited reversible color change from dark purple at pH 1.8 to yellowish-brown at pH 10.0, indicating that the PDABSA showed unusual pH-dependent color-changing properties on dyed wool fabrics.