Related Experiment Video
Updated: Jul 3, 2026
06:44
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Orientational ordering of crystal domains in ionic liquid based mixtures
Yusuke Imai1, Hiroshi Abe, Takefumi Goto
1Department of Materials Science and Engineering, National Defense Academy, Yokosuka 239-8686, Japan.
The Journal of Physical Chemistry. B
|July 18, 2008
Summary
Water and other molecules influence crystallization in ionic liquids. A slight amount of water induces a unique composite domain structure in [DEME][BF4] ionic liquid, a phenomenon also observed during thermal cycling.
Area of Science:
- Materials Science
- Crystallization Studies
- Ionic Liquid Research
Background:
- Ionic liquids (ILs) are versatile materials with unique properties.
- Understanding crystallization behavior in IL-rich phases is crucial for their applications.
- The influence of additives on IL crystallization is not fully understood.
Purpose of the Study:
- To investigate the effect of water, methanol, ethanol, and benzene on the crystallization of a hydrophilic ionic liquid, [DEME][BF4].
- To elucidate the role of water in inducing specific crystal domain structures.
- To explore the impact of water concentration on crystal morphology and orientation.
Main Methods:
- Simultaneous in situ X-ray diffraction and differential scanning calorimetry (DSC) were employed.
- Observations were conducted on an ionic liquid ([DEME][BF4])-rich phase with varying additives.
- Thermal cycling experiments were performed on the pure ionic liquid.
Main Results:
- Small amounts of water (0.9 mol %) induced a 'crystal-growth enhancement effect', forming a composite domain structure with weakly oriented microdomains.
- Higher water concentrations (above 2.9 mol %) led to the disappearance of this domain structure.
- Similar composite domain structures were observed in the pure [DEME][BF4] ionic liquid after thermal cycling, attributed to incidental water uptake.
Conclusions:
- Water acts as a significant structure-directing agent in the crystallization of [DEME][BF4] ionic liquid.
- A specific concentration of water is critical for the formation of the observed composite domain structure.
- The findings highlight the sensitivity of ionic liquid crystallization to trace amounts of water and thermal history.
Related Concept Videos
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
02:22Structures of Solids
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
01:18Unit Cells
A crystal's internal structure is an orderly array of atoms, ions, or molecules, and the details of this array significantly influence the solid's properties. In a crystal, periodically repeating 'structural motifs' - which could be atoms, molecules, or groups thereof - create a 'space lattice.' This is essentially a three-dimensional, infinite array of points, each surrounded by its neighbors in an identical way, forming the basic structure of the crystal.A 'unit cell' is a theoretical...
02:54Molecular and Ionic Solids
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
01:24The Seven Crystal Systems: Overview
Crystals with various point group symmetries belong to different crystal classes, which are synonymous terms. Despite being in the same class, crystals may have distinct shapes, like cubes and octahedra. There are 32 three-dimensional point groups, all of which are systematically divided into seven crystal systems.The basic cubic crystal system, exemplified by NaCl, features orthogonal vectors (α = β = �� = 90°) of equal lengths (a = b = c). When specific requirements are not imposed on the...
01:28Ionic Association
The ionic association is the association of oppositely charged ions in an electrolyte solution to form ion pairs. Bjerrum defined ion pairs as two oppositely charged ions whose electrostatic attraction exceeds the thermal energy of the system, typically expressed as 2kT. Electrostatic attraction depends on ionic charge, separation distance, and the dielectric constant of the medium. Thermal energy, represented by kT, reflects the tendency of ions to move independently due to molecular motion.