Microstructural evolution and order-disorder transitions in mesoporous silica films studied by FTIR spectroscopy

Plinio Innocenzi*, Paolo Falcaro, David Grosso, Florence Babonneau

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Silica mesoporous thin films have been synthesised with a self-assembling process employing cetyltrimethylammonium bromide as the organic template and tetraethyl orthosilicate as the silica source. Mesoporous films with Pm3n cubic phase phases have been obtained and the films have been thermally treated in air with a progressive heating schedule from as-deposited up to 1000°C. The evolution of the microstructure has been studied with transmission Fourier transformed infrared (FTIR) spectroscopy. FTIR spectra of the as-deposited films have shown the presence of cyclic species, which at temperatures larger than 350°C have been no more observed. In the 1000-1300 cm-1 region several overlapped absorption bands have been detected. In particular, the pair LO3-TO3, the cyclic species absorption bands and the pair LO4-TO4 have been resolved. These last bands, in particular, are associated with disorder-order transitions in the silica microstructure. These disorder-induced optical modes are due to the large interface area and related to bond strains. The evolution of the bands in the 1000-1300 cm-1 region has been followed with the Berreman configuration, performing the transmission FTIR analysis at 45° with respect to the normal incidence angle. The LO3 band, which in silica sol-gel films is indicative of the network condensation and is activated by scattering of the light in the pores, was resolved as a single sharp band from 250°C.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium - Proceedings
EditorsC Sanchez, R.M. Laine, S Yang, C.J. Brinker
Pages271-281
Number of pages11
Volume726
Publication statusPublished - 2002
Externally publishedYes
EventOrganic/Inorganic Hybrid Materials 2002 - San Francisco, CA, United States
Duration: 1 Apr 20025 Apr 2002

Conference

ConferenceOrganic/Inorganic Hybrid Materials 2002
CountryUnited States
CitySan Francisco, CA
Period1/04/025/04/02

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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    Innocenzi, P., Falcaro, P., Grosso, D., & Babonneau, F. (2002). Microstructural evolution and order-disorder transitions in mesoporous silica films studied by FTIR spectroscopy. In C. Sanchez, R. M. Laine, S. Yang, & C. J. Brinker (Eds.), Materials Research Society Symposium - Proceedings (Vol. 726, pp. 271-281)