Journal
JOURNAL OF CHEMICAL PHYSICS
Volume 130, Issue 21, Pages -Publisher
AMER INST PHYSICS
DOI: 10.1063/1.3146810
Keywords
nucleation
Funding
- UK government's Engineering and Physical Sciences Research Council (EPSRC) [EP/E00119X/1]
- EPSRC [EP/E00119X/1] Funding Source: UKRI
Ask authors/readers for more resources
Fletcher's spherical substrate model [J. Chem. Phys. 29, 572 (1958)] is a basic model for understanding the heterogeneous nucleation phenomena in nature. However, a rigorous thermodynamic formulation of the model has been missing due to the significant complexities involved. This has not only left the classical model deficient but also likely obscured its other important features, which would otherwise have helped to better understand and control heterogeneous nucleation on spherical substrates. This work presents a rigorous thermodynamic formulation of Fletcher's model using a novel analytical approach and discusses the new perspectives derived. In particular, it is shown that the use of an intermediate variable, a selected geometrical angle or pseudocontact angle between the embryo and spherical substrate, revealed extraordinary similarities between the first derivatives of the free energy change with respect to embryo radius for nucleation on spherical and flat substrates. Enlightened by the discovery, it was found that there exists a local maximum in the difference between the equivalent contact angles for nucleation on spherical and flat substrates due to the existence of a local maximum in the difference between the shape factors for nucleation on spherical and flat substrate surfaces. This helps to understand the complexity of the heterogeneous nucleation phenomena in a practical system. Also, it was found that the unfavorable size effect occurs primarily when R < 5r(*) (R: radius of substrate and r(*): critical embryo radius) and diminishes rapidly with increasing value of R/r(*) beyond R/r(*)=5. This finding provides a baseline for controlling the size effects in heterogeneous nucleation.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available