Experimental estimation of the surface roughness distribution parameters in nanochannels

A statistical model of surface roughness is developed to calculate the molecular flows in nanosystems. In this model, surface asperities are represented by a set of flat microareas connected by edges with each other and having normals that differ from the normal to the mean level. A Solver PRO-M atomic force microscope is used to measure the following two parameters of the microscopic roughness of a hard disk: the slope along a scan line and the asperity height. A large experimental sample from the measured values of these parameters is used to obtain a distribution function density for the angle of inclination and conditional distributions (with parameters dependent on this angle) for the asperity height and the area of the triangle formed by the height and the sides of the angle. The latter conditional exponential distribution turns out to be more convenient for calculating random quantities. The results can be employed to simulate boundary conditions when calculating molecular flows by statistical Monte Carlo methods and to estimate the properties of new materials for protective surface coatings in the nanosystems containing gas flows.