Mesoporous monoliths of inverse bicontinuous cubic phases of block copolymer bilayers

Abstract

Solution self-assembly of block copolymers into inverse bicontinuous cubic mesophases is a promising new approach for creating porous polymer films and monoliths with highly organized bicontinuous mesoporous networks. Here we report the direct self-assembly of block copolymers with branched hydrophilic blocks into large monoliths consisting of the inverse bicontinuous cubic structures of the block copolymer bilayer. We suggest a facile and scalable method of solution self-assembly by diffusion of water to the block copolymer solution, which results in the unperturbed formation of mesoporous monoliths with largepore (425 nm diameter) networks weaved in crystalline lattices. The surface functional groups of the internal large-pore networks are freely accessible for large guest molecules such as protein complexes of which the molecular weight exceeded 100 kDa. The internal double-diamond (Pn3m) networks of large pores within the mesoporous monoliths could be replicated to self-supporting three-dimensional skeletal structures of crystalline titania and mesoporous silica.

A Morphological Transition of Inverse Mesophases of a Branched‐Linear Block Copolymer Guided by Using Cosolvents

“…[18] This method, the solvent-diffusion/ evaporation-mediated self-assembly (SDEMS) of BCPs,a llowed the solution self-assembly of bPEG-PS n on as tationary substrate under static conditions (see SI for ad etailed procedure). [18] This method, the solvent-diffusion/ evaporation-mediated self-assembly (SDEMS) of BCPs,a llowed the solution self-assembly of bPEG-PS n on as tationary substrate under static conditions (see SI for ad etailed procedure).…”

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We report here as trategy for influencing the phase and lattice of the inverse mesophases of as ingle branchedlinear block copolymer (BCP) in solution which does not require changing the structure of the BCP.T he phase of the self-assembled structures of the blockc opolymer can be controlled ranging from bilayer structures of positive curvature (polymersomes) to inverse mesophases (triply periodic minimal surfaces and inverse hexagonal structures) by adjusting the solvent used for self-assembly.B yu sing solvent mixtures to dissolve the blockc opolymer we were able to systematically change the affinity of the solvent towardthe polystyrene block, which resulted in the formation of inverse mesophases with the desired lattice by self-assembly of as ingle branched-linear blockc opolymer.O ur method was also applied to an ew solution self-assembly method for ab ranched-linear block copolymer on as tationary substrate under humidity,w hich resulted in the formation of large mesoporous films.O ur results constitute the first controlled transition of the inverse mesophases of blockc opolymers by adjusting the solvent composition.

The direct self-assembly of amphiphilic block copolymers (BCPs) into inverse bicontinuous structures in solution is an emerging strategy for creating highly ordered porous polymers with three-dimensionally interconnected networks of large pores. [1][2][3][4][5][6][7][16][17][18][19] We recently reported that diblock copolymers,composed of adendritic or branched hydrophilic block and ahydrophobic linear polymer block, preferentially self-assemble into triply periodic minimal surfaces (TPMSs) of the BCP bilayers in solution, resulting in the creation of polymer cubosomes having highly defined internal large-pore networks. [1][2][3][4][5][6][7][16][17][18][19] We recently reported that diblock copolymers,composed of adendritic or branched hydrophilic block and ahydrophobic linear polymer block, preferentially self-assemble into triply periodic minimal surfaces (TPMSs) of the BCP bilayers in solution, resulting in the creation of polymer cubosomes having highly defined internal large-pore networks.

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“…[1][2][3][4][5][6][7][8][9] In am anner similar to the self-assembly of lipids such as monoolein into colloidal particles of inverse bicontinuous cubic mesophases (cubosomes) in water, [10][11][12][13][14][15] BCPs in solution could be directly self-assembled into colloidal particles of inverse bicontinuous cubic phases of the BCP bilayer (polymer cubosomes). [16][17][18] The TPMSs of the BCP bilayers exhibited distinct crystalline structures such as primitive cubic (Im3m,Psurface), double diamond (Pn3m,Dsurface), and gyroid (Ia3d,Gsurface) lattices,d epending on the architecture of the dendritic hydrophilic block as well as the block ratio between two distinct polymer domains.T he polymer cubosomes of these BCPs exhibited al arge surface area, which could be functionalized by implementing the desired functional groups through co-assembly with linear BCPs with a-functionalized hydrophilic blocks.M oreover,t he TPMSs of the BCP bilayer could be expanded to large-scale films by the diffusion of water under saturated humidity into ac oncentrated solution of BCP cast on as tationary substrate. [16][17][18] The TPMSs of the BCP bilayers exhibited distinct crystalline structures such as primitive cubic (Im3m,Psurface), double diamond (Pn3m,Dsurface), and gyroid (Ia3d,Gsurface) lattices,d epending on the architecture of the dendritic hydrophilic block as well as the block ratio between two distinct polymer domains.T he polymer cubosomes of these BCPs exhibited al arge surface area, which could be functionalized by implementing the desired functional groups through co-assembly with linear BCPs with a-functionalized hydrophilic blocks.M oreover,t he TPMSs of the BCP bilayer could be expanded to large-scale films by the diffusion of water under saturated humidity into ac oncentrated solution of BCP cast on as tationary substrate.…”

“…[1][2][3][4][5][6][7][16][17][18][19] We recently reported that diblock copolymers,composed of adendritic or branched hydrophilic block and ahydrophobic linear polymer block, preferentially self-assemble into triply periodic minimal surfaces (TPMSs) of the BCP bilayers in solution, resulting in the creation of polymer cubosomes having highly defined internal large-pore networks. [18] Our previous studies suggested that the branched architecture of the hydrophilic block played ac rucial role in the preferential self-assembly of branched-linear BCPs (Scheme 1) into inverse mesophases by affecting the chain dimension of the hydrophobic block with respect to the bilayer plane. [18] Our previous studies suggested that the branched architecture of the hydrophilic block played ac rucial role in the preferential self-assembly of branched-linear BCPs (Scheme 1) into inverse mesophases by affecting the chain dimension of the hydrophobic block with respect to the bilayer plane.…”

Selective oxidation of cyclohexene through gold functionalized silica monolith microreactors

“…Of particular importance is the ability to obtain accurate and reproducible control over the reaction conditions such as temperature, pressure and reaction solvent. [9,11] Furthermore, monolithic devices (microreactors containing a porous network of typically silica or other oxide materials) can be functionalized extensively with enzymes [12], magnetic nanoparticles [11] and other functional groups [12][13][14] in order to tailor their catalytic properties such as selectivity and activity. [10,15].…”