Ordered mesoporous titania from highly amphiphilic block copolymers: tuned solution conditions enable highly ordered morphologies and ultra-large mesopores

Abstract

Crystalline transition metal oxides with controlled mesopore architectures are in increasing demand to enhance the performance of energy conversion and storage devices. Solution based block copolymer self-assembly routes to achieve ordered mesoporous and crystalline titania have been studied for more than a decade, but have so far mostly been limited to water and alcohol dispersible polymers. This constraint has limited the accessible morphology space as well as structural dimensions. Moreover, synthetic approaches are mostly performed in a trial-and-error fashion using chemical intuition rather than being based on well-defined design parameters. We present solubility design guidelines that facilitate coassembly with highly amphiphilic block copolymers, enabling the formation of ordered structures with diverse length scales (d 10 ¼ 13.8-63.0 nm) and bulk-type morphologies. Thus, highly ordered and crystalline titania with the largest reported pores (d ¼ 32.3 nm) was demonstrated for such a coassembly approach without the use of pore-expanders. Furthermore, the use of an ABC triblock terpolymer system led to a 3D ordered network morphology. In all cases, subsequent calcination treatments, such as the CASH procedure, enabled the formation of highly crystalline mesoporous materials while preserving the mesostructure.

Ordered Mesoporous to Macroporous Oxides with Tunable Isomorphic Architectures: Solution Criteria for Persistent Micelle Templates

“…79 2) The large hydrophilic-hydrophobic contrast represented by the high Flory-Huggins interaction parameter drives phase separation of the blocks and enables modulation of the reorganization kinetics based upon the presented solution conditions. [80][81][82][83] 3) The polymer is simple to synthesize in diverse laboratory settings by atom transfer radical polymerization (ATRP) using a chain extension from commercial PEO homopolymers. Different size PEO macroinitiators were synthesized by the esterification of commercial poly(ethylene glycol)methyl ether with 2-bromopropionic acid ( Figure S1).…”

Wet Imprinting of Channel‐Type Superstructures in Nanostructured Titania Thin Films at Low Temperatures for Hybrid Solar Cells

“…From this analysis of the samples before and after polymer extraction, it can be concluded that both domain sizes of the titania nanostructures are smaller than those of the titania:PEO composite. This shrinkage is ascribed to collapse of the titania nanostructures induced by removal of the polymer scaffold . Moreover, the polymer‐extraction process enables interconnection of the nanostructured titania to form a network, which allows transport of charge carriers to the electrode in the hybrid solar cells.…”

“…This shrinkage is ascribed to collapse of the titania nanostructures induced by removal of the polymer scaffold. [8,37,57,58] Moreover,t he polymer-extraction process enables interconnection of the nanostructured titania to form an etwork, which allows transport of charge carrierst othe electrode in the hybrid solar cells. After polymer extraction,m esopores and nanostructures are present inside the titania films, which is in line with the observation of the sample surface.…”

Ordered mesoporous crystalline titania with high thermal stability from comb-like liquid crystal block copolymers

“…[4][5][6][7] In particular, TiO 2 , as an excellent semiconductor, has attracted enormous attention in recent years due to its promising applications in the photodegradation of organic dyes, [8][9][10] dye-sensitized solar cells (DSSCs), 11 lithium ion batteries (LIB), 12-14 photodissociation of water 15,16 and xation of carbon dioxide, 17 etc. [4][5][6][7] In particular, TiO 2 , as an excellent semiconductor, has attracted enormous attention in recent years due to its promising applications in the photodegradation of organic dyes, [8][9][10] dye-sensitized solar cells (DSSCs), 11 lithium ion batteries (LIB), 12-14 photodissociation of water 15,16 and xation of carbon dioxide, 17 etc.…”