Surface Morphology Analysis of LB SA Coatings

The surface morphology of the formed coatings based on LB SA films deposited onto the Si surface were studied by atomic force microscopy (AFM) using an NT-MDT Ntegra AFM probe microscope (NT-MDT, Zelenograd, Russia). Si substrate was chosen due to its availability, and it has a hydrophilic surface with a contact angle of less than 90°, like quartz. The scanning was carried out in a semi-contact mode with a frequency of 1 Hz. NSG01 probes (NT-MDT, Zelenograd, Russia) with a probe curvature radius of less than 10 nm were used for scanning. The obtained images with a resolution of 256 × 256 pixels were processed using the Gwyddion 2.61 software package [33 (link),34 (link)] to calculate the roughness and surface area of the film. The film roughness was calculated by the formula: $$R_a=\frac{1}{N}{{\displaystyle \sum }}_{j=1}^N\left|r_j\right|$$
where R_a is the arithmetic mean of the absolute values of the profile deviations within the base length (middle line of the profile), N is the number of points where the deviation is measured, and r_j is the deviation of the absolute value from the midline of the profile at a point.