Synthesis of Diisocyanate-Containing Thiophenes and Their Use in PDMS-Based Segmented Polymers

A synthesis route to siloxane-based thermoplastic elastomers (TPE) with functional hard blocks is described. The photophysical functionality is provided by oligothiophenes, namely terthiophene and bithiophene. Polyaddition of isocyanate-bearing thiophenes and amine-terminated siloxanes yields polymers incorporating a bisurea structure motive. Phase separation and strong hydrogen bonds provide ordering of the thiophenes, which is shown by wide-angle X-ray scattering (WAXS) and X-ray powder diffraction (XRD). Fluorescence measurements reveal a strong red shift of emission of polymer films compared with polymer solutions, thus confirming the existence of hard block segments with an enhanced pi system and higher charge-carrier mobility. Tuning of the optical band gap by different polymer compositions and various post polymerization treatments is demonstrated.