Related Experiment Video
Updated: Feb 3, 2026

Improved Polydimethylsiloxane (PDMS) Double Casting via Silicone Oil Treatment for Densely Packed Microstructure Replication
Published on: July 18, 2025
Modifying interfacial interparticle forces to alter microstructure and viscoelasticity of densely packed particle
Syed Ehsanur Rahman1, Nader Laal-Dehghani2, Sourav Barman3
1Department of Mechanical Engineering, Texas Tech University, 2500 Broadway, Lubbock, TX 79409, United States.
Hypothesis:
It is possible to control the absolute and relative magnitude of repulsive and attractive interactions and hence microstructure of interfacial particles at and air/water interface by adjusting subphase composition. It should be possible to modify interfacial viscoelasticity from elastic to viscous behavior through these changes to interfacial microstructure.
Experiments:
Particle laden interfaces are made from micron sized polystyrene at an air/water interface. The inter-particle interactions are controlled by the subphase salt concentration and addition of both non-ionic and ionic surfactants. These interfaces are then characterized using an interfacial rheometer with a custom visualization system.
Findings:
Three distinct microstructures are observed. Low repulsion and high attraction systems exhibit a soft glassy rheology with a disordered but dense microstructure. Creating high repulsion results in a dense hexagonal crystal. Finally, in systems with reduced repulsion and attraction, a hexatic phase can be observed. Each of these microstructures exhibit unique interfacial viscoelastic behavior. These results indicate that control over the properties of these interfaces, and hence Pickering emulsions, is possible through manipulation of interparticle forces.
Related Concept Videos
Protein-protein Interfaces
Dense Connective Tissue
Dense Regular Connective Tissue
In dense regular connective tissue, fibers are arranged parallel to each other, enhancing its tensile strength and resistance to stretching in the direction of the fiber orientations. Ligaments and tendons are made of dense regular...
Basic Postulates of Kinetic Molecular Theory: Particle Size, Energy, and Collision
Alterations in Respiration II
In Biot's breathing, the respiratory rate and depth are irregular, alternating between periods of deep gasping and apnea. Common causes...
Intermolecular Forces in Solutions
When the strengths of the intermolecular forces of attraction between solute and solvent species in a solution are no different than those present in the separated components, the solution is formed with no accompanying energy change. Such a solution is called an ideal solution. A mixture of ideal gases (or gases such as helium and argon,...
Interfacial Electrochemical Methods: Overview

