Molecular hydration: Interfacial supersolidity and its functionality.

[Display omitted] • Hydration dissolves an organic trunk into molecular dipoles wrapped with lone pairs and protons. • Solute interacts with solvent via O:H attraction, H ↔ H and O:⇔:O repulsion, with polarization. • Polarization shortens and stiffens the H-O but the O:H responses to polarization contrastingly. • Repulsion disrupts the bonding network and surface stress by fragmentation of the solution. Interaction between an organic molecular solute and its hydrating H 2 O molecules is of great importance to processes varying from cryopreservation, denaturation of protein and DNA, and drug-cell interaction, to chemical, healthcare, and food and pharmaceutical sciences and technologies. However, the nature and functionality of the interfacial states, at the sub-molecular level, are particularly poorly known. On the views of solvation charge injection, electronic polarization, and bonding network disruption, we show experimental evidence for the interfacial supersolidity and its functionality on the performance of solutions. The asymmetrically distributed lone pairs and protons of the molecular solute interact with their unlike or alike of its hydrating H 2 O molecules to initiate the O:H attraction, H ↔ H repulsion or O:⇔:O compression associated with the molecule dipolar polarization, and solute–solute repulsion, without involvement of charge sharing or regular bond formation. Polarization lengthens the hydrating O:H and shortens the H-O, and repulsion does however the partitioned O:H-O bond contrastingly, which not only enriches the THz phonons but also results in the interfacial supersolidity characterized at H-O oscillating frequency ∼3450 cm−1. Solvation investigation of acids, alcohols, aldehydes, glycines, and sugars confirmed the prediction of the interfacial supersolidity and estimation of hydration cell size and the involvement of solute–solute repulsion. The solute dipolar polarizability distorts and the interfacial H ↔ H or O:⇔:O repulsivity disrupts the hydrogen bonding network. The bond relaxation, polarization, structure distortion, and network disruption modulate the hydrophilicity, surface stress, solubility, and solution viscosity. Findings not only improve the comprehension of the dynamics of molecular hydration and the functionality of the solutions but also offer efficient spectral means for identification and quantification of the interfacial hydration cell size and its supersolidity. [ABSTRACT FROM AUTHOR]