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

In recent years, there has been an 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 colour-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), were characterized by FT-IR, UV-Vis spectrophotometry and matrix assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). The redox property and thermal stability of the polymer products were studied by cyclic voltammetry (CV) and TGA analysis, respectively. The results proved that the resulting polymer reached to 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 colour change from dark purple at pH 1.8 to yellowish-brown at pH 10.0, indicating that the PDABSA showed unusual pH-dependent colour-changing properties on dyed wool fabrics.