Phase Transformation from Lamellar to Hexagonal in Mesostructured Silica Thin Films by a Water Vapor Hydrothermal Method

Abstract

The phase transformation from lamellar to 2-dimensional (2D) hexagonal structure has been observed in mesostructured silica thin films, synthesized using a self-assembly triblock copolymer (EO20PO70EO20, P123) as a template, during heat treatment under water vapor hydrothermal conditions.

Preparation and luminescent properties of Rh6G-doped lamellar, hexagonal, and cubic mesostructured SiO2 waveguides

“…The preparation method was described in our previous paper [15]. Preparation of Rh6G-doped lamellar, hexagonal or cubic mesostructured SiO 2 precursor solutions was modified from Ref.…”

“…Here, we prepared a highly ordered hexagonal mesoporous SiO 2 thin film on a silicon substrate, which serves as a cladding for the present waveguides, by a water vapor hydrothermal treatment method [15]. Then, Rh6G-doped SiO 2 arrays with three kinds of mesostructures were synthesized by adjusting the volume ratio of a triblock copolymer template in the precursor solution and then patterned on the SiO 2 clad film by soft-lithography.…”

Synthesis and characterization of highly organized mesoporous palladium-doped tin dioxide thin films for gas sensing

“…Such treatments have been observed earlier for silica materials. 35 In the case of silica thin films the humidity treatment at elevated temperatures led to a phase transformation of the thin film from lamellar to hexagonal. This behavior differs significantly to the tin oxide systems where usually the as-synthesized films show almost no mesostructural order.…”

Structure Transition from Hexagonal Mesostructured Rodlike Silica to Multilamellar Vesicles

“…Until now, various routes have been explored and diverse mesostructures have been constructed. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] For instance, the structure transition can be induced by posttreatment methods, such as heat, water vapor, and so on. [11][12][13][14] Alternatively, by tuning the hydrophilic/ hydrophobic volume ratio (V H /V L ) of the mixed nonionic surfactants, ordered mesoporous materials with different symmetries can be rationally designed.…”

“…[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] For instance, the structure transition can be induced by posttreatment methods, such as heat, water vapor, and so on. [11][12][13][14] Alternatively, by tuning the hydrophilic/ hydrophobic volume ratio (V H /V L ) of the mixed nonionic surfactants, ordered mesoporous materials with different symmetries can be rationally designed. 24 Through adjusting the amount of an anionic cotemplate and the volume of a swelling agent 1,3,5-trimethylbenzene (TMB) in a triblock copolymer templating system (Pluronic F127), highly ordered mesostructured silica with 2-D hexagonal (HEX) p6m or cubic Im3m j , Fm3m j , and Ia3d h structures in high purity can be easily obtained.…”