Influence of covalent structure and molecular weight distribution on the optical properties of alternating copolymers and oligomers with 1,2,3-triazole and 1,3,4-oxadiazole side groups

Series of alternating conjugated copolymers of thiophene-based monomers substituted with bulky and electron withdrawing 1,2,3-triazole and 1,3,4-oxadiazole pendant groups was synthesized and characterized. Either a Suzuki coupling approach with 1,4-phenylene, 2,5-bis(octyloxy)-1,4-phenylene and 9,9Dioctylfluorene-2,7-diyl boronates or the Stille reaction with 2,5-thiophenediyl stannane was used for polymer synthesis. The choice of the arylene or thiophene comonomers gives the opportunity to tune solubility, molecular weight and final optical/electrochemical properties of prepared polymers. We achieved improvements of the energetic levels (HOMO, LUMO and band gap). Moreover experiments comparing not only effects of polymer covalent structure but also evaluating the effect of molecular weight distribution on the optical properties using the SEC apparatus equipped by Diode Array Detector (SEC-DAD) and Fluorescence (FLD) detectors were performed. (C) 2017 Elsevier Ltd. All rights reserved.