Solution self-assembly of amphiphilic block copolymers into inverse bicontinuous cubic mesophases is an emerging strategy for directly creating highly ordered triply periodic porous polymer nanostructures with large pore networks and desired surface functionalities. Although there have been recent reports on the formation of highly ordered triply periodic minimal surfaces of self-assembled block copolymer bilayers, the structural requirements for block copolymers in order to facilitate the preferential formation of such inverse mesophases in solution have not been fully investigated. In this study, we synthesized a series of model block copolymers, namely, branched poly(ethylene glycol)-block-polystyrene (bPEG-PS), to investigate the effect of the architecture of the block copolymers on their solution self-assembly into inverse mesophases consisting of the block copolymer bilayer. On the basis of the results, we suggest that the branched architecture of the hydrophilic block is a crucial structural requirement for the preferential self-assembly of the resulting block copolymers into inverse bicontinuous cubic phases. The internal crystalline lattice of the inverse bicontinuous cubic structure can be controlled via coassembly of branched and linear block copolymers. The results presented here provide design criteria for amphiphilic block copolymers to allow the formation of inverse bicontinuous cubic mesophases in solution. This may contribute to the direct synthesis of well-defined porous polymers with desired crystalline order in the porous networks and surface functionalities.

We report here a strategy for influencing the phase and lattice of the inverse mesophases of a single branched-linear block copolymer (BCP) in solution which does not require changing the structure of the BCP. The phase of the self-assembled structures of the block copolymer 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. By using solvent mixtures to dissolve the block copolymer we were able to systematically change the affinity of the solvent toward the polystyrene block, which resulted in the formation of inverse mesophases with the desired lattice by self-assembly of a single branched-linear block copolymer. Our method was also applied to a new solution self-assembly method for a branched-linear block copolymer on a stationary substrate under humidity, which resulted in the formation of large mesoporous films. Our results constitute the first controlled transition of the inverse mesophases of block copolymers by adjusting the solvent composition.

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.

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][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). [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. [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. [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) i...

: Lack of the space in many diesel vehicles make it difficult to design and install the catalytic muffler to reduce emissions. For this reason, inlet part of the catalytic muffler is made of L-type which has lower flow uniformity than conventional I-type, and catalytic muffler has complex internal structure by various insertions, which affect the flow uniformity and pressure drop of the systems. In this work, the flow characteristics such as flow uniformity and pressure drop have been numerically investigated by changing such various geometries as inlet shape, porosity, and outlet shape inside the muffler with the three-dimensional turbulent incompressible flow solver. Total 4 different cases are considered in order to find optimal configurations of the catalytic muffler in view of high flow uniformity and low pressure drop. The results show that Case 2 which has no induction cone and outlet perforated pipe has higher uniformity index and lower pressure drop than others considered in this work.