Halogen‐Bond Mediated 3D Confined Assembly of AB Diblock Copolymer and C Homopolymer Blends

Abstract

Halogen‐bond driven assembly, a world parallel to hydrogen‐bond, has emerged as an attractive tool for constructing (macro)molecular arrangement. However, knowledge about halogen‐bond mediated confined‐assembly in emulsion droplets is limited so far. An I….N bond mediated confined‐assembly pathway to enable order‐order phase transitions is reported here. Compared to hydrogen bonds, the distinct features of halogen bonds (e.g., higher directionality, hydrophobicity, favored in polar solvents), offers opportunities to achieve novel nanostructures and materials. Polystyrene‐b‐poly(4‐vinyl pyridine) (PS‐b‐P4VP) AB diblock copolymer is chosen as halogen acceptor, while an iodotetrafluorophenoxy substituted C‐type homopolymer, (poly(3‐(2,3,5,6‐tetrafluoro‐4‐iodophenoxy)propyl acrylate), PTFIPA) is designed as halogen donor, synthesized via reversible addition‐fragmentation chain transfer (RAFT) polymerization. Formation of halogen bonding donor–acceptor pairs between the PTFIPA homopolymer and the P4VP segments presented in PS‐b‐P4VP, increase the volume of P4VP domains, in turn inducing an order‐to‐order morphology transition sequence: changing from spherical → cylindrical → lamellar → inverse cylindrical, by tuning the PTFIPA content and choice of surfactant. Subsequent selective swelling/deswelling of the P4VP domains give rise to further internal morphology transitions, creating tailored mesoporous microparticles, disassembled nanodiscs, and superaggregates. It is believed that these results will stimulate further examinations of halogen bonding interactions in emulsion droplets and many areas of application.

Halogen bonding regulated functional nanomaterials

“…reported an I•••N bond induced confined-assembly to realize the order-order phase transitions. 91 The halogen acceptor was chosen to be polystyrene-b-poly(4-vinyl pyridine) (PS-b-P4VP) AB diblock copolymer while halogen donor was an iodotetrafluorophenoxy substituted C-type homopolymer, (poly (3-(2,3,5,6-tetrafluoro-4-iodophenoxy) propyl acrylate), PTFIPA) (Figure 11). The core domain of the nanostructure was increased due to the halogen bonding donor-acceptor pairing between P4VP and PTFIPA, leading to an order-to-order structure transition.…”

“…To understand more about halogen-bond mediated assembly in emulsion droplets, Xihuang et al reported an I⋯N bond induced confined-assembly to realize order–order phase transitions. 91 Polystyrene-b-poly(4-vinyl pyridine) (PS- b -P4VP) AB diblock copolymer was chosen to be the halogen acceptor while the halogen donor was an iodotetrafluorophenoxy substituted C-type homopolymer, poly(3-(2,3,5,6-tetrafluoro-4-iodophenoxy)propyl acrylate), PTFIPA ( Fig. 11 ).…”

Hydrogen-bonded supramolecular polymer micelles with pH/photothermal-responsive carmofur release and combined chemo-photothermal therapy

“…Aiming at fabricating well-defined micellar particles, the emulsion-solvent evaporation method 25,26 is used to achieve 3D confined assembly from H-bonded supramolecular polymeric micelles. The morphologies and sizes of the obtained particles are characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS).…”

Poly(vinylpyridine)-containing block copolymers for smart, multicompartment particles

“…Zhu and coworkers applied poly(3-(2,3,5,6-tetrafluoro-4-iodophenoxy)propyl acrylate) (PTFIPA) as a halogen donor for PS- b -P4VP, which exhibited higher directionality, hydrophobicity, and favorable binding ability in polar solvents compared to the hydrogen bonding donors. 141 Furthermore, Gröschel and coworkers investigated the confined self-assembly of (polystyrene- b -poly(4-vinylpyridine)- b -poly( tert -butyl methacrylate)) (PS- b -P4VP- b -P t BMA) BCPs with various small molecule guests complexed with P4VP. Various hydrogen bond donors, including cholesteryl hemisuccinate (CHEMS), lauryl gallate, and 4-(4-octylphenylazo)phenol were compared with halogen donors based on (E)-1-(4-(alkyloxy)phenyl)-2-(2,3,5,6-tetrafluoro-4-iodophenyl)diazene with varying alkyl chain lengths (Fig.…”