Selective Swelling and Functionalization of Integral Asymmetric Isoporous Block Copolymer Membranes

Abstract

SNIPS stands for a membrane fabrication technique that combines the evaporation induced self‐assembly of the block copolymers and the classical nonsolvent induced phase separation. It is a one‐step readily scalable technique to fabricate integral asymmetric isoporous membranes. The prominent developments in the last decade have carved out a niche for SNIPS as a potential technique to fabricate next generation isoporous membranes. In the last decade, a rich polymer library and variety of membrane postmodification routes have been successfully implemented to fabricate SNIPS membranes having the desired pore functionality. Some of these membranes form soft nanochannels in hydrated state due to swelling of the pore wall, i.e., the pore forming block of the block copolymer. These membranes having soft nanochannels have demonstrated the potential to perform several challenging separation tasks in ultrafiltration and nanofiltration. This paper highlights the currently accessible pore functionality, the strategies to tune the swelling of the soft nanochannels, the potential applications, and future perspectives of these membranes.

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

“…One good example highlighting the selective pH-responsiveness is BCP membranes. 30,31 Nanoporous membranes with welldefined pore sizes and distributions were generated via microphase separation of BCPs, 32 where PVP chains constituted the pore surfaces. Upon changes in pH, controlled swelling/deswelling of the PVP segments allowed tunable pore structure, size, and water flux.…”

Well-Defined Nanostructures by Block Copolymers and Mass Transport Applications in Energy Conversion

“…Self-assembly results in the formation of highly ordered, dense pores in the upper thin selective layer which are uniformly perpendicular to the membrane surface [ 94 ]; pores of the lower layer which exhibit a sparse, disordered sponge-like interconnected pore channel are formed by NIPS [ 95 ]. This method of combining self-assembly (S) of BCP with nonsolvent-induced phase separation (NIPS) is named SNIPS [ 96 , 97 ]. As the first step of membrane formation via SNIPS is dissolution of BCP for self-assembly, different solvent parameters that affect the nanostructure (different selective solvents, mixed solvents, and solvent volatilization rate) discussed in the previous section also affect the membrane structure formed by the SNIPS method [ 98 , 99 , 100 ].…”

Modular Synthesis of Functional Block Copolymers by Thiol–Maleimide “Click” Chemistry for Porous Membrane Formation

“…9,10 Today, functional BCPs are produced in smaller quantities compared to typical commodities 11 but are gaining increasing interest, as they provide access to versatile properties by varying architecture and monomer composition. Possible applications range from high-end applications in the field of (electro)magnetic storage 12 to photonic materials, 13−16 lithography, 17 solar cells, 18,19 drug delivery, 20 membranes, 21,22 and many more. 5,23−26 Over the past two decades, more complex polymer architectures such as multiblock copolymers 27,28 and star or brush polymers 29,30 have been synthesized, and phase separation behavior of simple BCP architectures can easily be predicted due to a fundamental knowledge of the influence of various parameters, such as the degree of polymerization (DP n ), the block volume fraction ( f i ), and the monomer−monomer interaction characterized by the Flory−Huggins interaction parameter (χ i ) on the BCP self-assembly.…”