Tuning Structure and Properties of Graded Triblock Terpolymer-Based Mesoporous and Hybrid Films

Abstract

Despite considerable efforts toward fabricating ordered, water-permeable, mesoporous films from block copolymers, fine control over pore dimensions, structural characteristics, and mechanical behavior of graded structures remains a major challenge. To this end, we describe the fabrication and performance characteristics of graded mesoporous and hybrid films derived from the newly synthesized triblock terpolymer, poly(isoprene-b-styrene-b-4-vinylpyridine). A unique morphology, unachievable in diblock copolymer systems, with enhanced mechanical integrity is evidenced. The film structure comprises a thin selective layer containing vertically aligned and nearly monodisperse mesopores at a density of more than 10(14) per m(2) above a graded macroporous layer. Hybridization via homopolymer blending enables tuning of pore size within the range of 16 to 30 nm. Solvent flow and solute separation experiments demonstrate that the terpolymer films have permeabilities comparable to commercial membranes, are stimuli-responsive, and contain pores with a nearly monodisperse diameter. These results suggest that moving to multiblock polymers and their hybrids may open new paths to produce high-performance graded membranes for filtration, separations, nanofluidics, catalysis, and drug delivery.

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

“…PS-b-PMMA block copolymer membranes were prepared using two different molecular weights of PS-b-PMMA BCP (PS 135K -b-PMMA 19.5K and PS 160k -b-PMMA 160K ). Table 1 shows the different types of solvents and polymer compositions used for membrane preparation.…”

“…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.…”

Influence of block sequence and molecular weight on morphological, rheological and dielectric properties of weakly and strongly segregated styrene-isoprene triblock copolymers

“…They exhibit particular properties which are caused by the combination of different blocks most often leading to self-assembled periodic microphase separated structures. The application of block copolymers in modern material science varies from blends [5][6][7][8][9][10][11][12], nanopatterning [13][14][15][16][17][18] to membranes [19][20][21][22][23][24][25][26][27].…”

Mesoporous monoliths of inverse bicontinuous cubic phases of block copolymer bilayers

“…In addition, polymer films and monoliths that have a three-dimensional (3D) crystalline array of internal nanoporous networks can serve as soft templates for creating mesoporous semiconductor crystals for highly efficient optical and optoelectronic materials and multifunctional hybrid materials [8][9][10][11][12] . In spite of recent advances in synthesizing porous polymers with internal bicontinuous porous networks [13][14][15][16][17][18][19][20] , microphase separation of block copolymers (BCPs) in bulk, followed by a selective removal of the labile polymer domains, remains a dominant method to create a cubic crystalline array of bicontinuous nanopores in polymer films and monoliths 21,22 . This method relies on the slow motion of BCPs in bulk, which might impede rapid synthesis of large monoliths with highly organized bicontinuous arrays of pores such as bicontinuous cubic structures 23 .…”

“…Peinemann, Abetz, and others 14,[26][27][28][29][30][31] reported the synthesis of 3D porous polymers by non-solvent-induced phase separation of BCPs, which gives an integral asymmetric membrane with a highly ordered thin layer on top of a non-ordered sponge-like layer. Recently, Wiesner and co-workers 13,17 developed SIM 2 PLE (spinodal-decomposition-induced macro-and mesophases separation plus extraction by rinsing) method based on the phase separation of BCPs and spinodal decomposition between BCPs and oligomeric additives, rendering the resulting structures to be hierarchically porous polymer monoliths composed of ordered mesopores and randomly distributed macropores.…”