Assembly of two- and three-dimensionally patterned silicate materials using responsive soft templates

Abstract

We report a soft and straightforward method for synthesizing two- and three-dimensionally patterned silicate materials by phase separation using nonionic emulsion templates. Our liquid-state method involves, under controlled atmosphere, the mixing of a condensed silica solution with an oil-in-water emulsion in the presence of a solution of a nonionic emulsifier, Triton X-100. The preparation is stabilized using an organic solvent. The morphology of the silicate materials is significantly modified by changing the reaction conditions or the concentration of the reagents. Three-dimensionally macro and nanoporous continuous films and nanoporous individual spherical particles, both made of amorphous silica, are obtained. The structure of the films and particles is defined by the emulsion template. Films were on average 20 microm thick with a volume-based porosity of approximately 7 x 10(-2) cm(3) g(-1), with pore size correlating well with the size of the oil droplets in the templating emulsion. The siliceous films are bicontinuous leading to large surface areas and openly accessible pores. Individual spheres ranged in size from approximately 1 to 6 microm in diameter with nanoporous openings of 300 nm in diameter. The porosity and integrity of all materials are maintained upon calcination.

Porous protein–silica composite formation: manipulation of silicate porosity and protein conformation

“…Peaks of the endothermic heat released due to thermal oxidation of Triton X-100 appear between 270 C and 360 C in the pure silica system. 26 These peaks are generally shifted to higher temperatures, with onsets as high as 300 C and are broadened, indicating release from a variety of different local environments in the presence of protein. These data indicate a direct association between the surfactant and the protein, as is the case with methanol, aiding occlusion of organic material into the silica framework.…”

“…Siliceous inorganic-organic composite materials were synthesized using Triton X-100/octadecane/water emulsions as the scaffold material and tetramethoxysilane (TMOS) as the silica precursor according to the procedure described previously. 26 Briefly, a first solution consisting of a triton X-100/octadecane/water emulsion was prepared with an octadecane to Triton X-100 wt. % ratio of 5 : 1.…”

“…In a previous publication, we described a method of synthesis for the formation of porous patterned silicate materials using responsive soft templates where the porosity was controlled over two length scales. 26 Porosity on the nanometre length scale is controlled by oil swollen micelles formed via phase separation while pores micrometres in size are defined by the size of the emulsion oil droplets. With this method we are able to control the porosity of the final materials by varying the concentration of the dispersed phase.…”

2D Optical Gratings Based on Hexagonal Voids on Transparent Elastomeric Substrate

“…In this contest it is worth mentioning that 2D colloidal crystals are interesting and promising systems for micro and nanopatterning due to their periodicity and specific size [ 7 ]. In micro and nano patterning field, colloidal crystals can be employed as lithographic masks or as molds for the production of micro and nanostructures for light trapping applications [ 8 ] or for the realization of SERS (Surface Enhanced Raman Spectroscopy) substrates [ 9 ].…”

Preparation of Mesoporous/Macroporous Materials in Highly Concentrated Emulsions Based on Cubic Phases by a Single-Step Method

“…The first research works focused on porous organic polymers, − but porous inorganic oxides can also be obtained. Many examples show that applying sol–gel reactions in the external phase of concentrated and/or highly concentrated emulsions leads to the formation of macroporous and dual meso/macroporous inorganic oxides. ,− The first inorganic porous materials, prepared in emulsions, were described in 1997 by Imhof and Pine . In this early work, porous inorganic oxides materials with a narrow macropore size were obtained by adding the reagents to the external phase of isooctane-in-formamide emulsions .…”