Langmuir – Blodgett monolayers of SBA-15 particles with different morphologies

This study presents an optimized protocol for the deposition of mesoporous SBA-15 particles with platelet-like and rod-like morphologies on different types of supporting substrates using Langmuir-Blodgett methodology, resulting in the formation of monolayers with porosity orientation controlled by the type, i. e. the morphology, of particles used over large areas. The morphology of the SBA-15 particles and specifically their aspect ratio are essential for the orientation of the particles and, hence, the orientation of the intrinsic porosity. Deposition on a surface, establishes a layer of SBA-15 platelets with pores oriented perpendicular to the substrate, or a layer of SBA-15 rods with pores oriented parallel to the substrate. In both cases, the oriented SBA-15 particles can be deposited onto areas that are larger than square centimeter using Langmuir-Blodgett technique. SEM characterization demonstrates formation of uniform close-packed layer of oriented mesoporous SBA-15 silica particles. Additionally, the particles coverage of the surface is independent and unaffected by the type of supporting substrate, which allows convenient experimental performance without requiring surface or particle modifications. In conclusion, Langmuir – Blodgett is a convenient technique for deposition of mesoporous SBA-15 particles with different morphology types in order to obtain a close-packed layer. The methodology is suitable to create large area sensors, used in, for instance, bio-sensing applications.