Related Experiment Video
Updated: Jan 26, 2026
08:44
Assembly and Characterization of Polyelectrolyte Complex Micelles
Published on: March 2, 2020
11.5K
Condensation of Counterions Gives Rise to Contraction Transitions in a One-Dimensional Polyelectrolyte Gel
1Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854-8087, USA. jerrymanning@rcn.com.
Polymers
|April 11, 2019
Summary
Polyelectrolyte gels swell due to diffusion and Coulomb forces, balanced by network elasticity. A 1D model reveals a transition from stretched to collapsed states influenced by bead repulsion and counterion condensation.
Area of Science:
- Polymer Physics
- Soft Matter Physics
- Physical Chemistry
Background:
- Polyelectrolyte gels exist in equilibrium between swelling forces (polymer/counterion diffusion, Coulomb interactions) and network elasticity.
- Coulomb forces influence both Donnan osmotic pressure and polymer network stretching.
Purpose of the Study:
- To isolate and analyze the effect of polyelectrolyte expansion on gel volume.
- To investigate the behavior of a simplified 1D polyelectrolyte gel model.
Main Methods:
- Analysis of a "one-dimensional" polyelectrolyte gel model: a linear chain of charged beads connected by Hooke's law springs.
- Examination of the interplay between Coulomb interactions, counterion condensation, and spring stretching.
Main Results:
- Repulsive bead interactions significantly stretch the springs, even with counterion condensation.
- A quasi-abrupt transition is observed from a stretched to a partially collapsed state across a range of Coulomb strengths.
- Fluctuations between stretched and contracted conformations occur within this transition range.
- Decreasing solvent quality can lead to progressive collapse, especially if condensed counterions increase spring stiffness.
Conclusions:
- The 1D model demonstrates complex conformational changes in polyelectrolyte chains driven by electrostatic interactions and solvent quality.
- Counterion condensation plays a crucial role in modulating the gel's response to electrostatic forces and solvent conditions.
Related Concept Videos
02:39Phase Transitions: Vaporization and Condensation
20.8K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
20.8K
02:31Phase Transitions
22.9K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
22.9K
01:22Two-dimensional Gel Electrophoresis
7.3K
Two-dimensional gel electrophoresis is a high-resolution protein separation method first introduced by O' Farrell and Klose in 1975. This method involves protein separation by two dimensions, mass and charge, making it more accurate than one-dimensional gel electrophoresis.
The first dimension separation uses the isoelectric focusing or IEF technique performed on immobilized pH gradient (IPG) strips that separate proteins according to their isoelectric points.
Biological samples, such...
The first dimension separation uses the isoelectric focusing or IEF technique performed on immobilized pH gradient (IPG) strips that separate proteins according to their isoelectric points.
Biological samples, such...
7.3K
02:58Properties of Transition Metals
29.7K
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.
29.7K
01:33Aldol Condensation vs Claisen Condensation
7.8K
Aldol condensation is an acid or base-catalyzed condensation between aldehydes or ketones to give an α,ꞵ-unsaturated carbonyl compound. A base-promoted condensation between ester molecules to produce a ꞵ-ketoester is known as the Claisen condensation. In the presence of a base, both reactions involve deprotonation of the acidic α hydrogen to produce the corresponding enolates. The nucleophilic enolates attack their respective nonenolized carbonyl compound forming a tetrahedral...
7.8K
01:18Rise of Liquid in a Capillary Tube
3.2K
When very thin cylindrical tubes, called capillaries, are dipped in a liquid, the liquid rises or falls in the tube compared to the surrounding liquid. This phenomenon is called capillary action. Capillary action occurs due to the combination of two opposing forces: the cohesive forces of the liquid, which cause it to stick to itself and form a rounded shape, and the adhesive forces between the liquid and the walls of the container, which cause the liquid to be attracted to the container walls.
3.2K