Ultrasound and Temperature Study of Non-Equilibrium Phase Transitions in Surface-Bound Liquid Layers

TL;DR

This study investigates non-equilibrium phase transitions in surface-bound liquid layers using ultrasound and temperature measurements, revealing periodic temperature jumps linked to resonance frequency changes during slow heating and cooling.

Contribution

It introduces a novel experimental approach combining ultrasound and temperature sensors to study surface-bound liquid phase transitions and identifies conditions for synchronized temperature and resonance variations.

Findings

Discovered periodic temperature jumps of 7.5-13 K in liquids.

Established correlation between temperature jumps and ultrasound resonance frequency.

Identified conditions involving ac fields for studying phase transitions.

Abstract

The present research deals with the registration and study of temperature and ultrasound parameters of non-equilibrium phase transitions occurring in the layer "liquid-solid surface" in the process of slow heating and cooling of the medium. Different resistive sensors have been used for taking measurements. As a result there has been discovered a periodic stepped dependence of the registered temperature with jumps ~7.5-13 K in water, water solutions and other liquids. We have studied the conditions under which the stepped temperature dependence of the resistive sensors indications is synchronous to the resonance frequency variations of the liquid volume limited by the surface of the axial piezoelectric resonator. The experiments showed that for studying temperature transitions and ultrasound phase velocity variations the following conditions are required: ac field in the area of the liquid surface layer. Assumed cause of the temperature jumps occurrence is high heat conduction and heat capacity of the surface-bound layer, causing local temperature variations on the surface of the resistive sensor in the process of evolution of the two-dimensional crystal liquid structure. Investigation of non-equilibrium transitions of the surface-bound liquid layer may be of interest for studying molecular complexes of liquid media, as well as cellular structures of living systems.