Meritev Soretovega koeficienta na posameznem mikrodelcu

Gregorin, Žiga (author), Osterman, Natan (mentor)

V magistrskem delu je predstavljen nov način merjenja Soretovega koeficienta $S_T$, torej razmerja med termodifuzijsko in difuzijsko konstanto delca, ki se izvaja na posameznem delcu v tekočini. Gretje in hlajenje mikrokapilare na robovih omogoča, da se znotraj merilnega območja vzpostavi konstanten temperaturni gradient, pri katerem je možno opazovati termoforezno obnašanje mikrodelcev v več temperaturnih območjih. Izkaže se, da optična pinceta ne omogoča merjenja dovolj majhnih sil, zato je poudarek na merjenju hitrosti lezenja delca. $S_T$ je izračunan iz dobljenih hitrosti, prikazano pa je tudi, da je termoforezna sila odvisna od temperature okolice.

• Language: Slovenian
• Keywords: termoforeza, Soretov koeficient, temperaturni gradient, koloidi, optična pinceta
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FMF - Faculty of Mathematics and Physics
• Year: 2018
• PID: 20.500.12556/RUL-102916
• COBISS.SI-ID: 3236196
• Publication date in RUL: 12.09.2018

GREGORIN, Žiga, 2018, Meritev Soretovega koeficienta na posameznem mikrodelcu [online]. Master’s thesis. [Accessed 14 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=102916

Secondary language

• Language: English
• Title: Soret coefficient measurements on a single particle

Abstract

A new way of measuring Soret coefficient $S_T$, ratio of thermal diffusion and diffusion coefficient, on a single particle in an aqueous solution is presented in the master's thesis. Heating and cooling of a microcapillary on the edges gives a constant value of temperature gradient along the whole measured area, allowing observation of the same sample at different temperatures. It turns out that optical tweezers do not allow measurements of small enough forces, caused by thermophoresis, so the emphasis is on particle drift velocity measurement. From acquired velocities, $S_T$ can be calculated and by measurements at different temperatures it is presented, that thermophoresis is dependent on absolute temperature of the environment.

• Keywords: thermophoresis, Soret coefficient, temperature gradients, colloids, optical tweezers