Semiconducting Fabrics by In Situ Topochemical Synthesis of Polydiacetylene: A New Dimension to the Use of Organogels

A diyne functionalized 4,6-O-benzylidene beta-D-galactopyranoside gelator, which can align its diyne motifs upon self-assembly (gelation) have been synthesized. The organogel formed by this gelator undergoes topochemical polymerization to polydiacetylene (PDA) under photoirradiation. This strategically designed gelator has been used to make semi-conducting fabrics. By developing the organogel on the fabrics, the gelator molecules were made not only to self-assemble on the fibers, but also to adhere to fabrics through hydrogen bonding. UV irradiation of the gel-coated fabric/fiber resulted in the formation of PDA on fibers. The benzylidene motif could be deprotected to get PDA with pendant free sugars that strongly bind to the cotton fibrils through multiple hydrogen bonds. Conductivity measurements revealed the semiconducting nature of these fabrics.