Gibbs-Thomson effect

The articles Kelving equation , Gibbs-Thomson effect and curvature effects overlap thematically. Help me to better differentiate or merge the articles (→ instructions ) . To do this, take part in the relevant redundancy discussion . Please remove this module only after the redundancy has been completely processed and do not forget to include the relevant entry on the redundancy discussion page{{ Done | 1 = ~~~~}}to mark. Acky69 ( discussion ) 16:38, Apr 5, 2013 (CEST)

The Gibbs-Thomson effect (named after Josiah Willard Gibbs and William Thomson ; not to be confused with the Thomson effect ) is a consequence of the interfacial energy in physical chemistry . This means that small liquid droplets (i. E. Particles with a strong surface curvature ) has a higher effective vapor pressure having as a planar phase boundary (liquid-gas) because small droplets, the interface compared to the volume of liquid is greater.

A generalization of the Gibbs-Thomson effect allows the explanation of Ostwald ripening , in which larger particles grow and smaller ones dissolve in disperse systems of small particles by means of diffusion .

The Gibbs-Thomson equation for a particle with radius is: ${\ displaystyle r}$

{\ displaystyle {\ frac {p} {p _ {\ text {Saturation}}}} = \ exp \! \ left ({\ frac {r _ {\ text {critical}}} {r}} \ right)}

With

p - partial pressure of the droplet-forming substance
p _saturation - saturation pressure of the droplet-forming substance
${\ displaystyle r _ {\ text {critical}} = {\ frac {2 \ cdot \ gamma \ cdot V _ {\ text {molecule}} ^ {\ text {drops}}} {k _ {\ mathrm {B}} \ cdot T}}}$ ${\ displaystyle r _ {\ text {critical}} = {\ frac {2 \ cdot \ gamma \ cdot V _ {\ text {molecule}} ^ {\ text {drops}}} {k _ {\ mathrm {B}} \ cdot T}}}$
- ${\ displaystyle \ gamma}$ - Surface energy of the drop in J / m².
- ${\ displaystyle V _ {\ text {molecule}} ^ {\ text {drops}} = {\ frac {V} {N}}}$ - Volume of a molecule in the drop or volume per number of particles
- k _B - Boltzmann constant
- T - temperature in Kelvin .

Because of the increase in the internal pressure due to the curved phase boundary (see Young-Laplace equation ), there is also a decrease in the melting temperature inside small particles . Sometimes this is also referred to as the Gibbs-Thomson effect.