Thermophoresis

Thermophoresis (also thermomigration, thermodiffusion, the Soret effect, or the Ludwig–Soret effect) is a phenomenon observed in mixtures of mobile particles where the different particle types exhibit different responses to the force of a <a href="/facts/Temperature_gradient/YhWj21zy">temperature gradient</a>. This phenomenon tends to move light molecules to hot regions and heavy molecules to cold regions. The term thermophoresis most often applies to <a href="/facts/Aerosol/X1jXFLp2">aerosol</a> mixtures whose <a href="/facts/Mean_free_path/6M7eofRq">mean free path</a> 
 
 
 
 λ
 
 
 {\displaystyle \lambda }
 
 is comparable to its <a href="/facts/Characteristic_length/eeEqbSw3">characteristic length</a> scale 
 
 
 
 L
 
 
 {\displaystyle L}
 
, but may also commonly refer to the phenomenon in all <a href="/facts/Phase_(matter)/NkHXDdN3">phases of matter</a>. The term Soret effect normally applies to liquid mixtures, which behave according to different, less well-understood mechanisms than gaseous <a href="/facts/Mixture/tms8rbmn">mixtures</a>. Thermophoresis may not apply to thermomigration in solids, especially multi-phase alloys.

Thermophoresis open-in-new

Thermophoresis