Related Experiment Video
Updated: Jun 6, 2026
11:04
Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature
Published on: December 20, 2016
Density and surface tension of ionic liquids.
C Kolbeck1, J Lehmann, K R J Lovelock
1Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany.
The Journal of Physical Chemistry. B
|December 15, 2010
Summary
Ionic liquids based on bis[(trifluoromethyl)sulfonyl]imide and imidazolium cations show density and surface tension changes with alkyl chain length. Longer chains decrease density, while surface tension plateaus, with ethylene glycol functionalization increasing both properties.
Area of Science:
- Physical Chemistry
- Materials Science
Background:
- Ionic liquids (ILs) are tunable solvents with unique properties.
- Understanding their physical characteristics like density and surface tension is crucial for applications.
Purpose of the Study:
- To investigate the impact of cation structure and anion type on the density and surface tension of ionic liquids.
- To establish structure-property relationships for bis[(trifluoromethyl)sulfonyl]imide-based and imidazolium-based ILs.
Main Methods:
- Density measurements using the vibrating tube method.
- Surface tension measurements using the pendant drop method.
- Surface composition analysis via angle-resolved X-ray photoelectron spectroscopy (ARXPS).
Main Results:
- Density decreases with increasing alkyl chain length in the [C(n)C(1)Im][Tf(2)N] series.
- Surface tension decreases with alkyl chain length, plateauing for chains longer than n=8.
- Ethylene glycol functionalization increases both density and surface tension.
- Anion effects on density and surface tension were observed within specific IL subgroups.
Conclusions:
- Alkyl chain length significantly influences the density and surface tension of imidazolium-based ILs.
- Intermolecular interactions and surface composition dictate these physical properties.
- ARXPS confirmed the absence of surface-active contaminants, ensuring data reliability.
Related Concept Videos
01:24Surface Tension
Surface tension is defined as the force per unit length (γ) acting along the surface of a liquid. It arises due to strong intermolecular forces of attraction. A molecule located inside the bulk of the liquid is surrounded by other molecules and experiences equal forces in all directions. However, a molecule at the surface experiences unbalanced forces because there are more neighboring molecules below than above. This creates a net inward force that pulls surface molecules toward the interior,...
02:57Surface Tension, Capillary Action, and Viscosity
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
01:22Surface Tension of Fluid
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies with...
Surface tension varies with...
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...
03:13Intermolecular Forces
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...
03:13Intermolecular Forces
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...