Multiple evidences of dynamic heterogeneity in hydrophobic deep eutectic solvents

Area of Science:

• Physical Chemistry
• Materials Science
• Computational Chemistry

Background:

• Hydrophobic deep eutectic solvents (HDESs) are increasingly utilized in various extraction processes.
• Understanding the molecular dynamics of HDESs is crucial for optimizing their performance.

Purpose of the Study:

• To investigate the influence of organic acid tail length on the dynamics of DL-menthol (DLM) based HDESs.
• To elucidate the hydrogen bonding characteristics and translational motion within these systems.

Main Methods:

• Atomistic molecular dynamics simulations were performed.
• Analysis included hydrogen bond relaxation, translational dynamics, and dynamic heterogeneity.

Main Results:

• Two distinct hydrogen bond relaxation modes were observed, with stronger interactions between menthol and acid carbonyl/hydroxyl groups.
• Translational dynamics and molecular caging effects were dependent on the acid tail length, slowing down with increasing length.
• Dynamic heterogeneity was evident in all simulated HDESs, with faster relaxation observed for DLM-C6.

Conclusions:

• The tail length of the organic acid significantly impacts the dynamics of DL-menthol based HDESs.
• Shorter chain acids, like hexanoic acid, facilitate faster molecular diffusion and relaxation.
• These findings provide insights into the structure-dynamics relationship of HDESs for targeted applications.