Clickable Bifunctional and Vertically Aligned Mesoporous Silica Films

Getting oriented mesoporous thin films with functionalized pores accessible from the substrate surface remains one key challenge in materials science, and jumping the step forward to multifunctional layers with perpendicular nanochannels has still to be achieved. Here, a general method is introduced combining the electrochemically assisted deposition of ordered and oriented azide- and thiol-functionalized mesoporous silica with a selective sequential azide-alkyne and thiol-ene click chemistry approach to prepare nanostructured and vertically aligned hybrid films bearing tunable amounts of organofunctional groups. High-resolution electron microscopy is used to evidence the high level of mesostructural order and pore orientation, while the effectiveness of the functionalization processes is proven from spectroscopic and electrochemical measurements. Voltammetric data also demonstrate that both the accessibility through the films and the properties of the incorporated functions are maintained upon derivatization. Feasibility of this simple and generic strategy is illustrated here for two couples of model derivatives (ethynylcobaltocenium/vinylferrocene and propargyl alcohol/allyl cyanide) but such stepwise postfunctionalization can be extensively used for the incorporation of a variety of organic functions in mesoporous silica films.