EFFECT OF SMALL PARTICLE SIZES ON THE EQUILIBRIUM CRYSTAL SHAPE AND THE WORK OF NUCLEUS FORMATION

For the sake of simplicity the formation of cubic nucleus on cubic particles is considered. It is demonstrated that small particles are "sucked in" by the nucleus and the equilibrium shape is a cube with shortened and restricted crystal thickness and width from which a part equal to the particle volume is taken off. We could name this shape a "crystal shell" with reduced edges, while the crystal-nucleus remains in equilibrium with reduced volume. It is shown that crystal thickness and width depend not only on the supersaturation and wettability, but also on the small particle sizes. Decrease of the crystal width is observed with increasing of the particle size, which (at complete and better-than-complete wetting) reaches the size of the particle itself. The nucleus is presented by the particle size. The size of the new phase can be very small, thus leading to reduction of the discrepancy between theory and the experiment shown by VEHKAMKI et al. [(6)]. The work for nucleus formation also decreases, following the change of the critical dimension (the width). Thus we see the effect of small particle size on the equilibrium shape and on the work for nucleation. We observe a similar effect in the experimental works of ZHANG et al. [(8)] and Lu et al. [(9)], who remark the size effect on the adsorption of molecules onto nanocrystaline particles.