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A synthetic method that taps into the facile Lewis base (LB)→Lewis acid (LA) adduct forming reaction between the semiconducting polymeric LB and all carbon LA C60 for the construction of covalently linked donor-acceptor dyads and brush polymer of dyads is reported. The polymeric LB is built on poly(3-hexylthiophene) (P3HT) macromers containing either an alkyl or vinyl imidazolium end group that can be readily converted into the N-heterocyclic carbene (NHC) LB site, while the brush polymer architecture is conveniently constructed via radical polymerization of the macromer P3HT with the vinyl imidazolium chain end. Simply mixing of such donor polymeric LB with C60 rapidly creates linked P3HT-C60 dyads and brush polymer of dyads in which C60 is covalently linked to the NHC junction connecting the vinyl polymer main chain and the brush P3HT side chains. Thermal behaviors, electronic absorption and emission properties of the resulting P3HT-C60 dyads and brush polymer of dyads have been investigated. The results show that a change of the topology of the P3HT-C60 dyad from linear to brush architecture enhances the crystallinity and Tm of the P3HT domain and, along with other findings, they indicate that the brush polymer architecture of donor-acceptor domains provides a promising approach to improve performances of polymer-based solar cells.

Direct access to nanostructured hydrogel networks through high fidelity photocuring of sphere-forming block copolymer melts is demonstrated. Hydrophobic junction points within the hydrogel network are based on an underlying lattice of body-centered cubic spheres (SBCC), produced via melt-state self-assembly of blended AB diblock and ABA triblock copolymer amphiphiles. Integrated thermally stable photocuring chemistry allows for in situ trapping of these spherical domains, independent from the required melt processing necessary to achieve the highly ordered BCC lattice. Swelling of the photocured solids in aqueous (and organic) media afforded highly elastic gels exhibiting excellent mechanical properties (G′ ∼ 103Pa) and complete preservation of the cured solid shape. The hydrogels fabricated in this study were produced from partially epoxidized (19.6%, relative to diene repeat units) blends of polybutadiene-b-poly(ethylene oxide) diblock (PB–PEO, fPB= 0.13, Mn= 29 500 g mol–1, 88.5 mol %) and PB–PEO–PB triblock (fPB= 0.13, Mn= 59 000 g mol–1, 11.5 mol %) copolymers synthesized via anionic polymerization. Addition of UV-activated cationic photoinitiator (4-iodophenyl)diphenylsulfonium triflate (0.5 mol %) produced composite samples exhibiting a highly ordered SBCCmorphology after annealing at moderate temperatures (4 h at 80 °C or 60 s at 140 °C) above the PEO melting transition. Composite films (0.33 mm thickness) were then photocured directly from the melt state, postanneal. Cured samples retained the SBCCstructure with extremely high fidelity, effectively prestructuring the network of junction points prior to swelling. The photopatterning potential of these uniquely designed hydrogels is also demonstrated. [ABSTRACT FROM AUTHOR]

Asymmetric polystyrene−polylactide (PS-PLA) bottlebrush block copolymers have been shown to self-assemble into a cylindrical morphology with large domain spacings. PLA cylinders can be selectively etched out of the shear-aligned polymer monoliths to generate nanoporous materials with an average cylindrical pore diameter of 55 nm. The remaining bottlebrush backbone provides a functional, hydrophilic coating inside the nanopores. This methodology significantly expands the range of pore sizes attainable in block copolymer based nanoporous materials. [ABSTRACT FROM AUTHOR]