Surface energy, stress, capillary-elastic pressure and chemical equilibrium constant in nanoparticles

The subject of this investigation is to discuss first the meaning of the su rface stress, surface energy and capillary-elastic pressure (CEP) of solid particles. After that, we present a general relation which links the CEP to the ratio of the chemical equilibrium constant corresponding to nano and l arge size particles. Knowing the chemical composition for both systems, the value of the CEP in situ can be determined. Conversely, knowing the value of the CEP and of the equilibrium constant for large particles, we obtain t he value of the constant for nano particles. A short discussion is finally devoted to the step chemical potential. The reaction of nickel carbonyl fro m nickel and carbon monoxide is discussed in detail as an illustration. (C) 2000 Elsevier Science B.V. All rights reserved.