Fabrication of mesoporous titania aerogel film via supercritical drying

Three-Dimensional Titanium Dioxide Nanomaterials

“…The pore size of the sol−gel films prepared from titania sols without any additives can be tuned in a very broad range from a few nanometers 149 to a few hundred of nanometers by variation of the sol composition and the aging conditions. 146,150 The range of available porous morphologies and pore size can be extended even further by the use of different additives and templating agents to the precursor solution, 149,151,152 which will be addressed more in detail later. The as-deposited titania gels are typically amorphous, not fully condensed, and contain large amounts of organic substances such as residual ligands, nonevaporated solvents, or additives.…”

“…One of the interesting techniques enabling fabrication of highly porous crystalline titania films at low temperatures is supercritical extraction. Using supercritical drying in CO 2 , Sung et al 150 prepared thick (ca. 1 μm) and highly porous titania films with about 76% porosity without any porogens.…”

Preparation of monolithic titania aerogels with high surface area by a sol–gel process combined surface modification

“…TiO 2 aerogel and its element doped aerogels have been widely produced by sol-gel methods, followed by controlling drying process of gels. [8][9][10][11][12][13] As is well known, the drying process of gels is a key factor for the preparation of aerogels, and mainly has supercritical drying and ambient pressure drying. The present monolithic or particulate TiO 2 aerogels are usually obtained by supercritical drying.…”

Ultraporous nanocrystalline TiO2-based films: synthesis, patterning and application as anti-reflective, self-cleaning, superhydrophilic coatings

“…More recently, anatase aerogel films with a porosity of 68 vol% were achieved by supercritical drying, however this is a cumbersome method that is not compatible with industrial production. 11 Another drawback associated with these thermal effects is the fragmentation of a layer above a typical thickness of 400 nm that is created by the lateral tensile stress accompanying the network solidification. The denser the film is, the thinner is the cracking threshold.…”