From Micelle Supramolecular Assemblies in Selective Solvents to Isoporous Membranes

Abstract

The supramolecular assembly of PS-b-P4VP copolymer micelles induced by selective solvent mixtures was used to manufacture isoporous membranes. Micelle order in solution was confirmed by cryo-scanning electron microscopy in casting solutions, leading to ordered pore morphology. When dioxane, a solvent that interacts poorly with the micelle corona, was added to the solution, polymer-polymer segment contact was preferential, increasing the intermicelle contact. Immersion in water gave rise to asymmetric porous membranes with exceptional pore uniformity and high porosity. The introduction of a small number of carbon nanotubes to the casting solution improved the membrane stability and the reversibility of the gate response in the presence of different pH values.

Nanostructured double hydrophobic poly(styrene-b-methyl methacrylate) block copolymer membrane manufactured via a phase inversion technique

“…Previous studies showed isoporous membranes were prepared using di-or trisolvent systems. 10,12,14 Initially, we prepared membranes using mono-and di-solvent mixtures, however, the morphologies of the PS-b-PMMA membranes did not show an ordered pore morphology ( Fig. S1 ESI †).…”

“…[14][15][16] We have shown previously that this technique can be applied to produce nanoporous membranes using the amphiphilic BCPs (PS-b-PEO and PS-b-P4VP). 12.14 Several research groups also demonstrated that this method is viable to produce nanoporous asymmetric BCP membranes However, all the membranes were produced from amphiphilic block copolymers, which contain at least one hydrophobic and one or more hydrophilic segment.…”

“…14,17,19,21 It was demonstrated that the hydrophilic group plays a crucial role in self-assembly and pore formation during the phase inversion process. In the NIPS method, water (non-solvent) has been commonly used as a precipitant for membrane formation.…”

Ferrocene-Modified Block Copolymers for the Preparation of Smart Porous Membranes

“…As described in the introduction, the microphase separation of block copolymers in solvent mixtures can be advantageously used for the preparation of integral asymmetric membranes by SNIPS process [42,43,46,57]. In general, the pore structure formation is tremendously influenced by a variety of parameters such as, e.g., evaporation time, solvent mixture, additives like salts, humidity, temperature, etc.…”

“…[42,43,46,57] In general, the pore structure formation is tremendously influenced by a variety of parameters such as, e.g., evaporation time, solvent mixture, additives like salts, humidity, temperature, etc. [44,[57][58][59]. Recently, the Abetz group elucidated the influence on membrane formation by using scattering methods [58].…”