Mechanically stable and photocatalytically active TiO₂/SiO₂hybrid films on flexible organic substrates

Abstract

Photocatalytic porous coatings (micro-, meso-and macroporous) are obtained by the dispersion of TiO 2 nanoparticles in sol-gel hybrid matrices. The sol-gel silica matrix is used as a binder stabilizing the nanoparticle dispersion and as a protective layer for the organic substrates. Organic groups are introduced into the matrix to induce the film flexibility and a part of them is used to create the final microstructure allowing remarkable improvement of the photocatalytic properties. The film structure and UV stability are fully characterized. The photocatalytic activity is evaluated through a test with formic acid. Flexible efficient photoactive composites are obtained showing important capabilities for depollution (water and air) and self-cleaning applications.

Well-Organized Meso-Macroporous TiO2/SiO2Film Derived from Amphiphilic Rubbery Comb Copolymer

“…33 The selective, preferential interaction between TTIP and POEM chains allowed the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 TiO 2 framework as a result of thermal shrinkage upon calcination. [34][35][36] The POEM domain was also burnt out during annealing process, but provided space for TTIP to convert into TiO 2 inorganic walls. In this study, the average molecular weight of PDMS-g-POEM comb copolymer was approximately 14,400 g/mol, with a ratio of PDMS:POEM = 1:1.5.…”

Long‐term stability of invisible X‐ray fluorescence identification tags

“…For the model samples, a low viscosity type of ink was developed, designed, and optimized for inkjet printing, which was selected for creating homogenous layers. The ink was formulated using a recently reported oligomeric siloxane binder, which proved to be useful for bonding oxide nanoparticles as well as having suitable rheological properties for inkjet printing . The ink was prepared by mixing 4 ml of stock siloxane binder solution (20 wt.% in anhydrous ethanol) with 4 ml of the oxide dispersion (40 wt.% in Dowanol PM solvent) and 8 ml of isobutanol.…”

Solution-processed crack-free oxide films formed using SiO2 nanoparticles and organoalkoxysiloxane precursors

“…When the organoalkoxysiloxanes were mixed with water, the hydrolysis reaction occurred as shown in equation (1). The surface of SiO 2 NPs in the bottle was covered with hydroxyl groups to achieve a stable dispersion.…”

“…SiO 2 nanoparticles (NPs) can be used to form sol-gel coatings in applications with a limited thermal budget, such as deposition onto polymer or paper substrates [1,2]. The sol-gel reaction is a versatile method, enabling control over the thickness, uniformity and thermal stability [3].…”