A series of well-defined amphiphilic di- and triblock copolymers have been synthesized, using atom transfer radical polymerization, with poly(ethylene glycol) (PEG) and poly(methacrylisobutyl polyhedral oligomeric silsesquioxane) P(MA-POSS) as the hydrophilic and hydrophobic blocks, respectively. The detailed self-assembly behavior of the amphiphilic macromolecules in aqueous media was studied using both static and dynamic light scattering (SLS and DLS) techniques. The evolution of block copolymer micelle formation in THF/water mixture (20/80 v/v) was monitored as the THF evaporated from the solvent mixture. Initially the block copolymer chains existed as unimers in solution, followed by the formation of smaller aggregates (R(h) < 2 nm) after 30 min, eventually growing in size to reach an equilibrium size when all the THF evaporated within 24 h. The micelles formed by the block copolymers were found to be kinetically unstable (not frozen); i.e., they tended to revert to individual copolymer chains on dilution. The hydrodynamic radii, R(h), of the micelles varied with the degree of polymerization (DP) of the hydrophobic P(MA-POSS); for example, for PEG(5K)-b-P(MA-POSS), an increase from R(h) approximately 13.3 +/- 1.1 nm to R(h) approximately 17.5 +/- 1.4 nm was observed with a nominal change in the DP of P(MA-POSS) from 4 to 6. The micelles formed by the triblock copolymers (P(MA-POSS)-b-PEG(10K)-b-P(MA-POSS)) were comparable in size to the diblock copolymer micelles; e.g., R(h) approximately 14.0 +/- 1.3 nm was found for P(MA-POSS)(4)-b-PEG(10K)-b-P(MA-POSS)(4). The micellar structures created by the triblocks in aqueous media were "flowerlike", where the PEG middle block adopted a loop conformation in the micelle corona. In addition to micelles, larger aggregates formed by P(MA-POSS)-b-PEG(10K)-b-P(MA-POSS) were also detected in solution. The larger aggregates may suggest a contribution from some PEG blocks adopting an extended conformation with one end dangling in solution, causing gelation at higher copolymer concentrations via intermicellar interactions. The P(MA-POSS)(4)-b-PEG(10K)-b- P(MA-POSS)(4) formed a gel in water at approximately 8.8 wt % copolymer concentration. No gel formation by diblock copolymers was observed; however, the addition of a small amount of triblock copolymer to an aqueous solution of diblock copolymer results in gel formation. Finally, rheological behavior of the obtained gels was also investigated.

We describe a versatile and scalable strategy toward long-range and periodically ordered mesoporous alumina (Al 2 O 3 ) structures by evaporationinduced self-assembly of a structure-directing ABA triblock copolymer (F127) mixed with aluminum tri-sec-butoxide-derived sol additive. We found that the separate preparation of the alkoxide sol−gel reaction before mixing with the block copolymer enabled access to a relatively unexplored parameter space of copolymerto-additive composition, acid-to-metal molar ratio, and solvent, yielding ordered mesophases of two-dimensional (2D) lamellar, hexagonal cylinder, and 3D cage-like cubic lattices, as well as multiscale hierarchical ordered structures from spinodal decomposition-induced macro-and mesophase separation. Thermal annealing in air at 900 °C yielded well-ordered mesoporous crystalline γ-Al 2 O 3 structures and hierarchically porous γ-Al 2 O 3 with 3D interconnected macroscale and ordered mesoscale pore networks. The ordered Al 2 O 3 structures exhibited tunable pore sizes in three different length scales, <2 nm (micropore), 2−11 nm (mesopore), and 1−5 μm (macropore), as well as high surface areas and pore volumes of up to 305 m 2 /g and 0.33 cm 3 /g, respectively. Moreover, the resultant mesoporous Al 2 O 3 demonstrated enhanced adsorption capacities of carbon dioxide and Congo red dye. Such hierarchically ordered mesoporous Al 2 O 3 are well-suited for green environmental solutions and urban sustainability applications, for example, hightemperature solid adsorbents and catalyst supports for carbon dioxide sequestration, fuel cells, and wastewater separation treatments.

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Conventional heat treatments to generate well‐ordered and crystalline mesoporous oxide and carbon structures are limited by long durations and annealing temperatures that can cause mesostructural collapse. This paper describes a facile strategy coupling block copolymer‐directed self‐assembly with high‐power Joule heating to form highly crystalline and well‐ordered mesoporous oxide and carbon nanostructures within second timeframes. The combined approach is compatible with various functional self‐assembled hybrid systems with a range of crystallization temperatures, generating mesoporous composites of γ‐Al2O3‐carbon, γ‐Al2O3/MgO‐carbon, and anatase‐TiO2‐carbon with p6mm symmetry, non‐close‐packed mesoporous carbon, as well as hierarchical mesoporous α‐Fe2O3‐carbon structures. Removing the polymer/carbon gives well‐defined, highly crystalline mesoporous all‐γ‐Al2O3 and all‐anatase‐TiO2 structures. Impregnation of chloroplatinic acid followed by Joule heating yields platinum nanoparticles decorated on the channel walls of mesoporous γ‐Al2O3‐carbon structures. The resultant Joule‐heating‐induced well‐ordered crystalline mesoporous oxide and oxide‐carbon structures have high thermal and structural stabilities and exhibit better performances in CO2 adsorption capacity and lithium‐ion batteries than conventional heat‐treated counterparts. This approach represents an energy‐efficient and time‐saving route toward ordered porous materials with high surface area and pore accessibility for a wide range of environmental applications such as carbon sequestration, renewable energy storage, and environmental filtration.

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