MOLECULAR-DYNAMICS OF THE PARTICLE SUBSTRATE CONTACT RUPTURE IN A LIQUID-MEDIUM/

The influence of a surrounding liquid on the process of rupture of con tact between a solid particle and a flat surface has been studied by m olecular dynamics simulations of a two-dimensional Lennard-Jones syste m. The computer experiments showed spontaneous particle escape and fac ilitation of contact rupture, i.e. less work had to be done to induce the rupture when a liquid was present. The adhesive force was, however , not reduced in the systems under investigation. The results show the role of the molecular structure of the liquid and solid phases, the s hape of solid surfaces in the contact zone and especially the impossib ility of liquid molecules penetrating into very narrow gaps between so lid surfaces in the course of contact rupture. The increased role of t he disjoining pressure fluctuations in the escape of the very small (m olecular size) particles has been elucidated. These peculiarities set the limits for a continuous thermodynamic approach to microscopic syst ems of this kind.