Unveiling the Mechanism of the Location of the Grafted Nanoparticles in a Lamellar-Forming Block Copolymer

Distinctive Dielectric Permittivity of Hierarchical Nanostructures with Ordered Nanoparticle Networks Self-Assembled from AB-g-NP/AC Block Copolymer Mixtures

Directing nanoparticles into ordered organization in polymer matrix to improve macroscopic properties of nanocomposites remains a challenge. Herein, by means of theoretical simulations, we show the high permittivity of hybrid nanostructures designed with mixtures of AB block copolymer-grafted nanoparticles and lamella-forming AC diblock copolymers. The grafted nanoparticles self-assemble into parallel stripes or highly ordered networks in the lamellae of the AC diblock copolymers. The ordered nanoparticle networks, including honeycomb-like and kagomé networks, provide bending and conductive pathways for concentrating electric fields, which results in the improvement of the permittivity. We envisage that this strategy will open a gateway to prepare hierarchically ordered functional nanocomposites with distinctive dielectric properties.

Computer simulation of zwitterionic polymer brush grafted silica nanoparticles to modify polyvinylidene fluoride membrane

Dissipative particle dynamics (DPD) simulations was adopted to investigate the modification of polyvinylidene fluoride (PVDF) membrane by adding zwitterionic polymer brush poly(sulfobetaine methacrylate)- tetraethyl orthosilicate (PSBMA-TEOS) grafted silicon nanoparticles (SNPs) to the casting solution. The effects of polymer concentration and grafting architecture (PSBMA length and SNPs grafting ratio) on membrane morphology are discussed. When the polymer concentration reaches 40%, part of the SNPs is embedded in the membrane; the optimal polymer concentration is around 25-30%. In the SNPs system with the grafting ratio of 1, some SNPs are eluted into solution during phase separation. Compared with different grafting architectures, M_8-5, M_10-5 and M_12-5 system (M_x-y, where x represents the length of the zwitterionic polymer brush and y represents the grafting ratio of the silica nanoparticles) exhibited stable membrane morphologies. This work can provide guidance for the design and modification of organic-inorganic composite membrane and help understand the distribution of modified materials on the membrane surface.