Dynamics and Glass Transition of Aqueous Solutions of Molecular Liquid, Polymer, and Protein Studied by Broadband Dielectric Spectroscopy

Abstract

Broadband dielectric spectroscopy (BDS) is the most powerful tool for observing the dynamics of molecules in an extremely wide frequency range between 1 μHz and 50 GHz or more, i.e., the time window between megaseconds and picoseconds that covers the dynamics of solids to liquids. The progress of the investigations using BDS on the dynamics of aqueous solutions of hydrophilic molecular liquids, polymers, and proteins from solid to liquid states in this decade is presented in terms of the glass transition. The relaxation process, ν-relaxation, originating from the local reorientational motion of water molecules and the α-relaxation originating from the cooperative motion of hydrated solute are strongly related. The universalities of the dynamical hierarchy from fast and local motion of water molecules to slow and global cooperative motion of hydrated guest molecules extending over a wide range of glass transition temperature are successfully explained by applying the theoretical interpretation of mixtures of van der Waals liquids using the coupling model. More complicated partially crystallized aqueous protein solutions are also included.

Disruption of the self-molecular association of pentanol in binary mixtures with alkylbenzoates: a dielectric relaxation spectroscopy study

“…The g f value for pure solvents is unity and it is close to unity for the binary mixtures with a lower concentration of pentanol or alkylbenzoate, which is an indication of the absence of or weak heteromolecular interaction respectively. 3 All pentanol/alkylbenzoates show a g f value that deviates from unity for the whole composition range and the presence of the re-alignment of dipoles of neighboring polar molecules. The g f value of MB is close to unity in the case of 2-pentanol and 3pentanol.…”

“…A non-linear result of a static and high frequency dielectric constant with increasing alcohol concentration for the heteroassociation of an alcohol with other polar solvents is reported in the literature. 3,5 In a dielectric spectroscopy study of the mixture of alkan-1-ol/alkylbenzoate, it is established that the effect of the alcohol concentration on the 3 a value is smaller in the case of longer chain alcohols. 9 Since the present work deals with long-chained alcohols, namely isomeric pentanols, the same conclusion can be drawn.…”

“…1 Dielectric relaxation spectroscopy 2 is a powerful tool to study intramolecular and intermolecular interactions in pure solvents and solvent binary mixtures. 1,3 There have been a number of studies carried out to gain insight into molecular interactions in polar binary mixtures and the nature of the interactions present in binary mixtures is yet to be conrmed and is the topic of scientic debate. 4,5 In the liquid state, a considerable change in dielectric properties takes place upon mixing.…”

Interfacial polarization of in vivo rat sciatic nerve with crush injury studied via broadband dielectric spectroscopy

“…The BDS covers frequencies between 1 μHz and 100 GHz, which correspond to the time window between megaseconds and picoseconds [16]. Furthermore, this frequency range covers the molecular dynamics of solid and liquid materials [17]. For BDS measurements, the material under test is sandwiched between electrodes and an alternate or direct current voltage is applied.…”