Thermophobic diffusion becomes dominant in ultra-dilute alkali halide aqueous solutions.

ABSTRACT: Under the influence of a temperature gradient, particles diffuse to their more favourable temperature, inducing a concentration gradient, a phenomenon termed thermodiffusion. The shift between thermophobic and thermophilic transport occurs at the inversion temperature T₀. Previous theories imply that only thermophobic behaviour, i.e. the absence of T₀, occurs at infinite dilution due to the absence of ion-ion interactions, but this has yet to be confirmed. In this study, phase-shifting interferometry visualisation experiments reveal that decreasing concentration leads to a more dominant thermophobic behaviour in different alkali halide (LiCl, NaCl, KCl, NaF and NaI) aqueous solutions. However, finite T₀ can still be observed at a low concentration of 0.02 m

SUBMITTER: Xu S 

PROVIDER: S-EPMC12518627 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature