Synthesis and characterization of donor–acceptor semiconducting polymers containing 4-(4-((2-ethylhexyl)oxy)phenyl)-4H-dithieno[3,2-b:2′,3′-d]pyrrole for organic solar cells

D–A polymers containing 4-(4-((2-ethylhexyl)oxy)phenyl)-4H-dithieno[3,2-b:2′,3′-d]pyrrole and 2,5-bis(2-ethylhexyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione were successfully synthesized and applied for organic solar cells.

Synthesis of poly(3-hexylthiophene) based rod–coil conjugated block copolymers via photoinduced metal-free atom transfer radical polymerization

Photo-mediated metal-free ATRP for the synthesis of P3HT-based rod–coil copolymers.

N-Benzoyl dithieno[3,2-b:2',3'-d]pyrrole-based hyperbranched polymers by direct arylation polymerization

BACKGROUND

Although poly(N-acyl dithieno[3,2-b:2',3'-d]pyrrole)s have attracted great attention as a new class of conducting polymers with highly stabilized energy levels, hyperbranched polymers based on this monomer type have not yet been studied. Thus, this work aims at the synthesis of novel hyperbranched polymers containing N-benzoyl dithieno[3,23,2-b:2',3'-d]pyrrole acceptor unit and 3-hexylthiophene donor moiety via the direct arylation polymerization method. Their structures, molecular weights and thermal properties were characterized via 1H NMR and FTIR spectroscopies, GPC, TGA, DSC and XRD measurements, and the optical properties were investigated by UV-vis and fluorescence spectroscopies.

RESULTS

Hyperbranched conjugated polymers containing N-benzoyl dithieno[3,23,2-b:2',3'-d]pyrrole acceptor unit and 3-hexylthiophene donor moiety, linked with either triphenylamine or triphenylbenzene as branching unit, were obtained via direct arylation polymerization of the N-benzoyl dithieno[3,23,2-b:2',3'-d]pyrrole, 2,5-dibromo 3-hexylthiophene and tris(4-bromophenyl)amine (or 1,3,5-tris(4-bromophenyl)benzene) monomers. Organic solvent-soluble polymers with number-average molecular weights of around 18,000 g mol-1 were obtained in 80-92% yields. The DSC and XRD results suggested that the branching structure hindered the stacking of polymer chains, leading to crystalline domains with less ordered packing in comparison with the linear analogous polymers. The results revealed that the hyperbranched polymer with triphenylbenzene as the branching unit exhibited a strong red-shift of the maximum absorption wavelength, attributed to a higher polymer stacking order as a result of the planar structure of triphenylbenzene.

CONCLUSION

Both hyperbranched polymers with triphenylamine/triphenylbenzene as branching moieties exhibited high structural order in thin films, which can be promising for organic solar cell applications. The UV-vis absorption of the hyperbranched polymer containing triphenylbenzene as branching unit was red-shifted as compared with the triphenylamine-containing polymer, as a result of a higher chain packing degree.

Healable shape memory (thio)urethane thermosets

(Thio)urethane networks combining SM properties and self-healability under mild temperature conditions via the DA chemistry were developed. The effect of various network architectures in SM-aided scratch healing was evaluated.

Efficient microencapsulation of a liquid isocyanate with in situ shell functionalization

A one-pot, simple approach for the encapsulation of a liquid tri-isocyanate in polyurea microcapsules with in situ shell functionalization/modification using different types of hydrophobic agents is presented.