Structure evolution of mesoporous silica under heavy ion irradiations of intermediate energies

• Published in: Microporous and mesoporous materials 2017-10, Vol.251, p.146-154
• Main Authors: Lou, Yu, Dourdain, Sandrine, Rey, Cyrielle, Serruys, Yves, Simeone, David, Mollard, Nicolas, Deschanels, Xavier
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemical Sciences; Ion irradiation; Mesoporous silica; Physics; Pore collapse; Radiation damage; Thin film
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2017.05.057

Mesoporous sol-gel silica thin films were irradiated with gold ions of medium energies from 0.5 MeV to 12 MeV. In all cases these porous materials are compacted as a result of mesopore collapse and deformation. X-ray reflectivity and SEM measurement show that the total compaction (densification) is achieved for a fluence of about 2 × 1014 cm−2 (∼5 × 1021 keV cm−3). The process of mesoporosity collapse seems different according to the irradiation regime (nuclear versus electronic). This effect results in a U-shaped evolution of the curve of the damage cross section as a function of the energy of ions Au. Infrared measurement of Au 0.5 MeV irradiated samples show a shift of TO3 band towards lower wavenumber, related to Si-O-Si bond angle and Si-O bond length change. The sol-gel mesoporous and nonporous samples exhibit a delayed shift compared to thermal nonporous ones, which indicates that sol-gel materials are more radiation tolerant from this point of view. The sensitivity of these mesoporous structures to the damage caused by irradiation opens interesting prospects for obtaining self-conditioning materials. [Display omitted] •Radiation damage on thin mesoporous silica film measured by X-rays Reflectivity.•Complete densification of the mesoporous film is observed for 5 × 1021 keV cm−3.•Sol-gel mesoporous silica films are more radiation tolerant than thermal ones.