Cantilever bending based on humidity-actuated mesoporous silica/silicon bilayers

• Main Authors: Christian Ganser, Gerhard Fritz-Popovski, Roland Morak, Parvin Sharifi, Benedetta Marmiroli, Barbara Sartori, Heinz Amenitsch, Thomas Griesser, Christian Teichert, Oskar Paris
• Format: Article
• Language: English
• Published: Beilstein-Institut 2016-04-01
• Series: Beilstein Journal of Nanotechnology
• Subjects: AFM cantilever; bilayer bending; grazing incidence small-angle X-ray scattering (GISAXS); mesoporous film; sorption-induced deformation
• Online Access: https://doi.org/10.3762/bjnano.7.56

We use a soft templating approach in combination with evaporation induced self-assembly to prepare mesoporous films containing cylindrical pores with elliptical cross-section on an ordered pore lattice. The film is deposited on silicon-based commercial atomic force microscope (AFM) cantilevers using dip coating. This bilayer cantilever is mounted in a humidity controlled AFM, and its deflection is measured as a function of relative humidity. We also investigate a similar film on bulk silicon substrate using grazing-incidence small-angle X-ray scattering (GISAXS), in order to determine nanostructural parameters of the film as well as the water-sorption-induced deformation of the ordered mesopore lattice. The strain of the mesoporous layer is related to the cantilever deflection using simple bilayer bending theory. We also develop a simple quantitative model for cantilever deflection which only requires cantilever geometry and nanostructural parameters of the porous layer as input parameters.