2018/05/09 by Wenyao Zhang, Zhang, Wenyao, Qiuwang Wang +5
Chemistry · Engineering · Physics and Astronomy · #Electrostatics and Colloid Interactions #FOS: Physical sciences #Field-Flow Fractionation Techniques #Fluid Dynamics (physics.flu-dyn) #Nanopore and Nanochannel Transport Studies #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.1805.03462
We found a fetal flaw in the manuscript, and we are expected to reformulate the model
openalex publication_date 2018/05/09 · arxiv created 2019/02/13 · arxiv updated 2019/02/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A systematic theoretical study of temperature-gradient-induced electrokinetic flow and thermoelectric potential of electrolyte solutions in a micro-/nanocapillary is presented. The study is based on a semi-analytical model developed by simultaneously solving the energy equation and the Poisson-Nernst-Planck/Navier-Stokes equations with the lubrication theory. The semi-analytical model is shown to be mainly governed by eight parameters, including two temperature-related parameters (temperature and its gradient), two electrokinetic parameters (ζ potential and the ratio of capillary radius to the Debye length κ0a) and four physical properties of cation and anion (i.e. Soret coefficient difference ΔST, average Soret coefficient ST, normalized difference in diffusivities χ and intrinsic Peclet number λ). It is found that the thermoelectric field is induced by three effects, which are respectively due to (1) the difference in the Soret coefficients of cation and anion; (2) the selective ion diffusion resulting from the temperature-modified Boltzmann distribution of ions; (3) the advective transport of ions caused by the fluid flow. The first thermoelectric effect prevails for lower ζ potentials or large κ0a, while the second is dominant for higher ζ potentials with very small κ0a. The first two thermoelectric effects can cooperate or counteract depending on the sign of ζΔST. Finally, the temperature-gradient-induced electrokinetic flow is found to be a superposition of an electroosmotic flow component due to the thermoelectric field and a thermoosmotic flow component due to the combined effects of osmotic pressure and dielectric body force. These two flow components may cooperate or counteract depending on values of ζ and κ0a.