Highly ordered "defect-free" self-assembled hybrid films with a tetragonal mesostructure

Paolo Falcaro, Stefano Costacurta, Giovanni Mattei, Heinz Amenitsch, Augusto Marcelli, Mariangela Cestelli Guidi, Massimo Piccinini, Alessandro Nucara, Luca Malfatti, Tongjit Kidchob, Plinio Innocenzi

Research output: Contribution to journalArticleResearchpeer-review

Abstract

One-pot self-assembled hybrid films were synthesized by the cohydrolysis of methyltriethoxysilane and tetraethoxysilane and deposited via dip-coating. The films show a high "defect-free" mesophase organization that extends throughout the film thickness and for domains of a micrometer scale, as shown by scanning transmission electron microscopy. We have defined these films defect-free to describe the high degree of order that is achieved without defects in the pore organization, such as dislocations of pores or stacking faults. A novel mesophase, which is tetragonal 14/mmm (space group), is observed in the films. This phase evolves but retains the same symmetry throughout a wide range of temperatures of calcination. The thermal stability and the structural changes as a function of the calcination temperature have been studied by small-angle X-ray scattering, scanning transmission electron microscopy, and Fourier transform infrared spectroscopy. In situ Fourier transform infrared spectroscopy employing synchrotron radiation has been used to study the kinetics of film formation during the deposition. The experiments have shown that the slower kinetics of silica species can explain the high degree of organization of the mesostructure.

Original languageEnglish
Pages (from-to)3838-3846
Number of pages9
JournalJournal of the American Chemical Society
Volume127
Issue number11
DOIs
Publication statusPublished - 23 Mar 2005
Externally publishedYes

    Fingerprint

ASJC Scopus subject areas

  • Chemistry(all)

Cite this