Application of molecular modelling for analysis of a surface energy and its comparison with the experimental results based on wetting angle measurement

In this paper we presented results of adsorption energy using molecular dynamics methods and comparison with contact experiment with 3% solution of IPA (isopropyl alcohol) and water on the silicon wafer. Two methods of surface energy of numerical calculation were applied in the presented research. The first one was based on obtaining surface energy by reproducing contact angle experiment at molecular level and corresponding contact angle evaluation using an elaborated fitting procedure. The second method was based on the surface energy calculation by determining the energy of liquid with vacuum layer, then silicon with vacuum and two materials mixed and vertical cross-section. In both cases the adhesion energy was calculated for crystallographic planes of silicon (110) and (111). Finally the numerical results were compared with the experimental ones, where the surface energy was obtained by measuring contact angle using a goniometer and surface tension from chemistry books. The results from simulations proves that surface energy was not smaller for (111) than for (110) crystallographic plane of a silicon. In fact the numerical methods give the physical values, but so far they don´t agree well with the experimental results. However the molecular modelling technique can be considered as a tool for prediction of a surface energy with further investigation and improvements.