Surface freezing at the alkane water interface under acoustic levitation

Abstract

This thesis investigates the surface freezing phenomenon between water and hexadecane that occur under acoustic levitation. The study examines the impact of impurities, potential surface-induced effects, and the role of the evaporation of the water droplet while acoustically levitated, on this phenomenon. Three purity levels of hexadecane were tested to assess impurity effects on freezing inhibition. Results suggest that impurities prevent freezing, contrary to the typical expectation where impurities often promote freezing. Surface-induced effects were evaluated through interfacial tension and spreading behavior studies, revealing minimal influence on freezing except, for the potential of creating a monolayer of organized molecules at the interface that could act as a nucleation point. Thermodynamic calculations and levitation experiments demonstrated that water evaporation contributes to freezing but may not be the sole factor. These findings highlight the need for additional investigations to fully understand the freezing mechanism, particularly regarding impurity interactions