Non-destructive testing of mechanical properties and thickness of Langmuir–Blodgett films by static force spectroscopy

Mechanical and mathematical models for calculating the physical and mechanical properties of single- and multilayer materials of nanometer thickness, selecting the contact point taking into account the type of interaction of the cantilever with the surface of the material, their advantages and disadvantages are presented. The possibility of calculating the thickness of multilayer materials by solving the inverse problem is shown. The structure and local physical and mechanical properties of Langmuir–Blodgett films based on poly(methyl methacrylate) and composite films containing 41.7; 83.3; 167; 333 mol of SiO 2 nanoparticles per 1 mol of polymer were analyzed using atomic force microscopy. The AFM1 program has been developed for analyzing static force spectroscopy data, which implements the selection of the contact point according to the Johnson–Kendall–Roberts (JKR) model, and the calculation of the elastic modulus values according to the Hertz, JKR, Hsueh–Miranda, Makushkin, and Menčik models. A comparison of the calculated values of the elastic modulus and coating thickness was carried out using the above models. It was found that the film thickness values calculated using the Makushkin model correlate with the experimental data obtained by creating an artificial defect in the film. The results obtained are relevant for diagnostics and analysis of the properties of new functional nanomaterials.