Asymmetric Organic–Inorganic Hybrid Membrane Formation via Block Copolymer–Nanoparticle Co-Assembly

Abstract

A facile method for forming asymmetric organic-inorganic hybrid membranes for selective separation applications is developed. This approach combines co-assembly of block copolymer (BCP) and inorganic nanoparticles (NPs) with non-solvent induced phase separation. The method is successfully applied to two distinct molar mass BCPs with different fractions of titanium dioxide (TiO2) NPs. The resulting hybrid membranes exhibit structural asymmetry with a thin nanoporous surface layer on top of a macroporous fingerlike support layer. Key parameters that dictate membrane surface morphology include the fraction of inorganics used and the length of time allowed for surface layer development. The resulting membranes exhibit both good selectivity and high permeability (3200 ± 500 Lm(-2) h(-1) bar(-1)). This fast and straightforward synthesis method for asymmetric hybrid membranes provides a new self-assembly platform upon which multifunctional and high-performance organic-inorganic hybrid membranes can be formed.

Block copolymer–nanoparticle composites: Structure, functional properties, and processing

“…The influence of nanofillers on the diffusivity of gas through polymeric membranes depends on A c c e p t e d M a n u s c r i p t 29 cyclophenyl surface ligands decreased the diffusivity of gases (O 2 , N 2 , and CO 2 ), whereas plain POSS increased diffusivity [248]. TiO 2 -containing PI-PS-P4VP BCP membranes exhibited higher permeability and selectivity for water [249]. Incorporation of multi-walled carbon nanotubes in PEO-polyacrylonitrile BCP membrane was found to improve the surface hydrophilicity of the membrane that can enhance the flux of hydrophilic solvents (e.g., water) and can decrease the flux of hydrophobic solvents [250].…”

Nanophase separation and structural evolution of block copolymer films: A “green” and “clean” supercritical fluid approach

“…1 Block copolymers can self-assemble into periodic domains via a process of microphase separation [2][3] and these systems, with controlled orientation and ordering have promise in a number of applications including nanolithography, membrane synthesis and nanofludics. [4][5][6][7] Solvent annealing of BCP films is an effective approach for obtaining ordered phase-separated thin films at low temperatures and in relatively short time periods since the solvent swells the polymer, creating free volume and providing the necessary chain mobility to the polymer blocks. [8][9] Generally, organic and halogenated solvents are preferred to swell one or more blocks within a polymer film, 10 even though they are toxic and have a negative environmental impact.…”

Porous Polyelectrolytes: The Interplay of Charge and Pores for New Functionalities

“…[77] This approach provided ar oute to nanoporous membranes with tunable applications for both ultrafiltration and nanofiltration without compromising the mechanical properties of the membrane. [78] Stamm and co-workers demonstrated the multifunctionality of nanoporous polyelectrolyte membranes in catalysis and pH-switchable filtration, whereby the pores arose from the random stacking of PS-b-P4VP particles. [79] Them embrane rejected 97 %l ysozyme protein and the permeation of water was pH-dependent.…”