Glycerol Hydrogen-Bonding Network Dominates Structure and Collective Dynamics in a Deep Eutectic Solvent.

Area of Science:

• Physical Chemistry
• Materials Science

Background:

• Deep eutectic solvents (DESs) offer tunable properties for various applications.
• Glyceline, a DES composed of choline chloride and glycerol, exhibits significantly lower viscosity than glycerol.
• Understanding the structure-dynamics relationship in DESs is crucial for optimizing their performance.

Purpose of the Study:

• To elucidate the microscopic structure and dynamics of the deep eutectic solvent glyceline.
• To investigate the role of glycerol and choline ions in defining glyceline's properties.
• To correlate the observed dynamics with potential applications.

Main Methods:

• Molecular dynamics simulations were employed to analyze the structural and dynamic behavior of glyceline.
• Analysis focused on hydrogen bonding networks, ion-molecule interactions, and diffusion coefficients.
• Comparison of glyceline's properties with pure glycerol.

Main Results:

• Glyceline's reduced viscosity is attributed to its unique structural network, primarily defined by glycerol.
• Glycerol forms a hydrogen-bonding network with complex microscopic dynamics.
• Choline ions are found in interstitial voids, showing minimal correlation with glycerol, and dominate local transport.

Conclusions:

• The glycerol component dictates the overall structural network and long-range dynamics of glyceline.
• Choline ions play a critical role in localized dynamics and transport, particularly relevant for applications in confined environments.
• Glyceline's distinct structural and dynamic characteristics make it suitable for applications where low viscosity and specific local transport are required.