Time-resolved in-situ X-ray diffraction study of the formation of 3D-hexagonal mesoporous silica films

摘要

Highly oriented 3D-hexagonal silica thin films have been produced on silicon substrates by dip-coating technique,using cetyltrimethylammonium(CTAB)bromide as structuring agent.For the first time,time-resolved in situ X-ray diffraction experiments have been used to investigate the formation of such mesostructured films.Interestingly,the data shows that an intermediate mesophase appears just after film deposition(t<500 ms),characterized by one diffraction peak centered at a d spacing of 65 A.Then after 20 s,another mesophase appears with a shorter d spacing(44 A),which corresponds to the 3D-hexagonal structure found for the final dried film.