A Facile Synthetic Route to Multifunctional Poly(3-hexylthiophene)-b-poly(phenyl isocyanide) Copolymers: From Aggregation-Induced Emission to Controlled Helicity

New synthetic methods are of great significance in enabling access to valuable compounds and materials. Although conjugated poly(3-hexylthiophene) (P3HT) has been widely investigated, P3HT copolymers containing functional groups (such as amino, imino, hydroxyl, etc.) are rarely reported because of inherent synthetic difficulties. Here P3HT copolymers bearing diverse functional pendants, which cannot be obtained by the direct block copolymerization of the corresponding monomers, were designed and facilely synthesized through the postpolymerization modification method. First, P3HT-b-poly(phenyl isocyanide) (P3HT-b-PPI) with pentafluorophenyl (PFP) ester was prepared in one-pot using Ni(dppp)Cl-2 as the catalyst. Then, through the postpolymerization modification of the copolymer with alcohols and amines, P3HT-b-PPIs copolymers bearing defined functional groups were facilely obtained. The introduction of functional pendants endowed P3HT-b-PPIs copolymers with diverse functionalities. When pyrene pendants were introduced into PPI block, the obtained copolymer presented both aggregation-induced emission (ATE) and aggregation-caused quenching (ACQ) properties when methanol was added into its THF solution. As for the copolymer containing chiral pendants, an excess of right-handed helix of the PPI backbone was induced after annealing in toluene at 100 degrees C for 7 days, and left-handed helical bundles were formed by the self-assembly of the annealed copolymer in THF. Meanwhile, the copolymer containing PEG pendants was amphiphilic and could self-assembled into worm-like or spherical structures in different solutions. In addition, cross-linked P3HT-b-PPI was obtained after postpolymerization modification of P3HT-b-PPI copolymer with glycol.