Templating effect of mesostructured surfactant-silica monolithic films on the surface structural and mechanical...

Mesostructured surfactant-silica monolithic films were prepared using a supramolecular templating method. The effect of the templating in the monolithic films on the interfacial interactions was evaluated and elucidated using the atomic force microscope techniques combined with other surface analyses to produce different surface structures and force curves depending on the surfactants. The transparent and flexible surfactant-silica monolithic films were prepared to exhibit the ordered nanostructures. The monolithic films templated by nonionic triblock copolymers (poly(ethylene oxide (EO))--poly(propylene oxide (PO))--poly(ethylene oxide (EO))) of EO₂₀PO₇₀EO₂₀ (P123) and EO₁₀₆PO₇₀EO₁₀₆ (F127) significantly exhibited flat surfaces and the higher viscoelastic properties which were supported by surface stiffness and adhesive force, whereas the monolithic film by cationic alkylammonium surfactant indicated a rough surface and the plastic deformation property by application of force. This indicated that the higher molecular weight of the EO and PO phases enhanced the phase segregation in the silica surfaces due to the higher solubility differences between both blocks to consolidate the surfactant-silica interfacial interactions. Therefore, the different surface structural and mechanical properties attributed to the interfacial organic-inorganic interaction patterns were successfully clarified.