Nanoscale Density Fluctuations in Ionic Liquid Binary Mixtures with Nonamphiphilic Compounds: First Experimental...

Area of Science:

• Materials Science
• Physical Chemistry
• Soft Matter Physics

Background:

• Ethylammonium nitrate (EAN) is an ionic liquid known to form complex structures with other compounds.
• Previous studies observed similar phenomena in EAN-alcohol mixtures, but explanations remain incomplete.
• Understanding mesoscopic organization is crucial for predicting material properties.

Purpose of the Study:

• To investigate the mesoscopic organization in mixtures of ethylammonium nitrate (EAN) and two nonamphiphilic compounds.
• To elucidate the underlying mechanisms of the observed phase behavior.
• To challenge existing models for EAN-based mixtures.

Main Methods:

• Wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) to probe structure at different length scales.
• Molecular dynamics (MD) simulations to provide atomistic insights into the organization.
• Analysis of macroscopic homogeneity versus microscopic phase separation.

Main Results:

• Observation of a complex mesoscopic organization in EAN and nonamphiphilic compound mixtures.
• Evidence of an ionic liquid-rich region percolating a molecular liquid-rich region.
• Absence of macroscopic phase separation despite the observed internal organization.

Conclusions:

• The study reveals a novel mesoscopic organization in EAN-nonamphiphilic systems.
• Existing models fail to explain this behavior with nonamphiphilic compounds.
• Further theoretical and experimental work is needed to fully understand this phenomenon.