Non-Equilibrium Block Copolymer Self-Assembly Based Porous Membrane Formation Processes Employing Multicomponent Systems

Abstract

Porous polymer-derived membranes are useful for applications ranging from filtration and separation technologies to energy storage and conversion. Combining block copolymer (BCP) self-assembly with the industrially scalable, non-equilibrium phase inversion technique (SNIPS) yields membranes comprising periodically ordered top surface structures supported by asymmetric, hierarchical substructures that together overcome performance tradeoffs typically faced by materials derived from equilibrium approaches. This review first reports on recent advances in understanding the top surface structural evolution of a model SNIPS-derived system during standard membrane formation. Subsequently, the application of SNIPS to multicomponent systems is described, enabling pore size modulation, chemical modification, and transformation to non-polymeric materials classes without compromising the structural features that define SNIPS membranes. Perspectives on future directions of both single-component and multicomponent membrane materials are provided. This points to a rich and fertile ground for the study of fundamental as well as applied problems using non-equilibrium-derived asymmetric porous materials with tunable chemistry, composition, and structure.

The permeability of diamond and other microphase-separated morphologies in copolymer films

“…One of the areas of practical use of block copolymers is the production of isoporous membranes for filtration of liquids and ion transport. 7–13 Compared to solid porous bodies with a substance or void (pore) at any point under consideration, soft matter, which includes polymers, is characterized by the interpenetration of its constituent components into each other. To describe their distribution, local characteristics are used, for example, concentration (or volume fraction) as a function of a point in space.…”

Polyacrylonitrile-containing amphiphilic block copolymers: self-assembly and porous membrane formation

“…Many more BCPs have been used to fabricate SNIPS membranes based on the deepened knowledge in the following years. 5,19,21 For example, the introduction of PHEMA as hydrophilic block bearing accessible hydroxy-moieties by Schöttner et al 22 paved the way to multiple post-modification possibilites. 23–26…”

“…Although valuable work has been published in this field, 4,19,21 there is still need for improvement regarding the membranes’ mechanical stability. Amongst others, 30 our group has approached this issue by incorporating UV-crosslinkable moieties into a methacrylate-based amphiphilic BCP prepared by ATRP, 31 leading to improved solvent resistance and mechanical stability.…”

“…68 From a viewpoint of application in the field of membranes, a certain chain length of the BCP segments as well as the controllability of the hydrophilic block content is of utmost importance in order to tailor the membrane formation process, and to tailor the pores’ sizes and properties. 21,69 For that reason, the protocols developed by Pietrasik and co-workers are adjusted and used for parts of this work.…”