The goal of present work was to clarify how the way of preparation of the multi-layered template-structured silica films influences their structure and accessibility with respect to doping dye molecules.

Multi-layered silica films on glass slides were prepared by dip-coating technique using sol-gel precursor (reagents molar composition was 1 Si(OC₂H₅)₄ : 22 C₂H₅OH : 5 H₂O : 0.004 HCl : 0.096 CH₃(CH₂)₁₅N⁺(CH₃)₃Br^–). The dip-coated silica films were calcined in air at 400 ºC for 1 h to complete condensation of siloxane oligomers into silica framework and to remove the template. Two alternative preparation routes that differ in the sequence of dip-coating and calcination steps were applied. The adsorption of Methylene Blue dye from 5·10^-5 M aqueous solution was studied in order to examine accessibility of pores in the developed multi-layered silica films.

It has been found out that in the case of preparation route which includes reiteration of dip-coating and calcination steps, only the pores of the top silica layer appeared to be accessible to dye molecules. In contrast, when the preparation route includes successive dip-coatings accomplished by calcination of the final multi-layered film, all pores were found to be accessible. This is due to formation of the pores which occurs via simultaneous removal of the template over the whole thickness of the multi-layered silica film.

One can observe that dip-coating over the top of uncalcined film results in multi-layered films of different thickness and surface uniformity depending on the intervals between dip-coatings. This could be caused by variation of hydrophilic-hydrophobic properties upon drying and ageing of the as-synthesised template-doped silica film. If each dip-coating step was accomplished with calcination for the template removal, no difference in dip-coating of the successive layers were observed although the developed multi-layered films appeared to be less promising for further functionalisation.

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