Influence of the dividing surface notion on the formulation of Tolman’s law

• Main Author: M T Horsch
• Format: Article
• Language: English
• Published: Salahaddin University-Erbil 2019-08-01
• Series: Zanco Journal of Pure and Applied Sciences
• Subjects: Nucleation theory; surface tension; nanodroplets; Tolman’s law; interfacial thermodynamics
• Online Access: https://zancojournals.su.edu.krd/index.php/JPAS/article/view/3111

The influence of the surface curvature 1/R on the surface tension γ of small droplets at equilibrium with a surrounding vapour, or small bubbles at equilibrium with a surrounding liquid, can be expanded as γ(R) = γ0 –2δ0/R + O(1/R2), where R = RL is the Laplace radius and γ0 is the surface tension of the planar interface, with zero curvature. According to Tolman's law, the first-order coefficient in this expansion is obtained from the planar limit δ0 of the Tolman length, i.e., the deviation δ = Re – RL between the equimolar radius Re and RL. Here, Tolman’s law is generalized such that it can be applied to any notion of the dividing surface, beside the Laplace radius, on the basis of a generalization of the Gibbs adsorption equation which consistently takes the size dependence of interfacial properties into account.