Introducing nanoscaled surface morphology and percolation barrier network into mesoporous silica coatings

Abstract

Mesoporous silica thin films were patterned at the sub-micron scale utilizing the ion hammering effect in order to combine the advantages of mesoporous character and surface morphology, while preserving the interconnected pore system or creating laterally separated porous volumes surrounded by nonpermeable compact zones. Porous silica coatings were prepared by sol-gel method with ordered and disordered pore system using micellar templates. Hexagonally ordered Langmuir-Blodgett type monolayer of silica spheres was applied as mask against Xe + ion irradiation. The ion energy was chosen according to Monte-Carlo simulations to achieve structures with high lateral contrast between irradiated and unirradiated, i.e., masked areas. The disordered pore system proved to be more resistant against ion bombardment. Although the created surface morphologies were similar, the main character of the pore system could be tailored to be interconnected or separated by controlling the ion fluence. Confocal fluorescent images and ellipsometric porosimetry measurements confirmed that the contribution of transition zone between the intact masked and damaged regions to the porosity is negligible. Furthermore, the majority of the porous volume can be preserved as interconnected pore system by the application of low ion fluence. By increasing the fluence value, however, separated porous volumes can be created at the expense of the total pore volume.

New Approach on Quantification of Porosity of Thin Films via Electron-Excited X-ray Spectra

“…In spectroscopic ellipsometry, a technique used for validation purposes in the present study, the change in polarization of the incident radiation is exploited to extract film properties by comparing with a model. The porosity is defined as the mixing ratio between material and air. , The mixing ratios of different media can be determined by using the effective medium approximation (EMA) method . A further optical method employed here, called interference fringes method (IFM), takes advantage from direct illumination of sufficiently thin porous samples, which causes multiple reflections of light at the layer(s) interfaces.…”

Mezopórusos szol-gél bevonatok: előállítás, jellemzés, alkalmazás

“…Vizsgálatainkat kiterjesztettük egy, az eddigi munkákban figyelmen kívül hagyott összefüggés, a pórusrendszer eredeti (rendezetlen vagy rendezett) jellege és az ionbesugárzás hatására kialakuló szerkezet közötti kapcsolat tanulmányozására. 13 …”

“…We proved experimentally that besides creating surface morphology, the character of the pore system of SiO 2 coatings can be tailored to be interconnected or separated by controlling the ion fluence of the Xe + ion bombardment ( Figure 9 and Figure 10). 9,13 …”

Novel method for the production of SiC micro and nanopatterns

“…Co and Pt ions were used to achieve nanopatterns through a nanoporous alumina mask [17]. Mesoporous silica thin films were patterned by Xe + through a Langmuir-Blodgett film [18].…”