Structure, thermodynamics and dielectric properties of water under nanoscale confinement and search for reversible phase change of methanol in astrochemical conditions

Abstract

This thesis majorly explores the intricate structural, dynamical, and dielectric characteristics of monolayer water and other organic molecules under strong confinement and astrochemical condition. Water molecules confined within hydrophobic nanocavities display anomalous structural and dynamic behavior. The structural, dynamical, and thermodynamic properties of water confined within nanopores of diverse geometries are of fundamental importance due to their potential applications in various nanofluidic devices, such as ion-selective channels, ionic transistors, sensors, molecular sieves, desalination systems, and blue energy harvesters. Apart from worldly applications, confined water studies also hold the potential to understand the ice that exists in comets, interstellar medium, and in water giants like Neptune. Unlike terrestrial ice, astrochemical ice shows unique characteristics due to extreme conditions in space. Confinement serves as a model system to emulate such ice structures in laboratory conditions. In the list of detected molecules outside Earth, after water, methanol is the most abundant complex organic molecule. Methanol serves as a precursor in the formation of several higher-order complex organic molecules such as glycols and aldehydes, and it mostly exists in ice form in the interstellar medium. Therefore, in this study, apart from fundamental studies on confined water, we have also investigated the ice structure of methanol, which is of significant astrochemical importance