Hydrodynamic Measurement of Double-Layer Repulsion between Colloidal Particle and Flat Plate

• Published in: Science (American Association for the Advancement of Science) Vol. 231; no. 4743; pp. 1269 - 1270
• Main Authors: Prieve, Dennis C., Alexander, Barbara M.
• Format: Journal Article
• Language: English
• Published: Washington, DC The American Association for the Advancement of Science 14.03.1986; American Association for the Advancement of Science
• Subjects: Applied sciences; Cell adhesion; Colloids; Debye length; Electricity; Electrolytes; Electrostatic apparatus and appliances; Electrostatic devices; Electrostatics; Exact sciences and technology; Flow velocity; Hydrodynamics; Magnetism; Other techniques and industries; Paints & painting industry; Particle energy; Particle motion; Particles; Particulate matter; Potential energy; Speed
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.231.4743.1269

Electrostatic repulsion acting across an electrolyte solution lends stability to paints and printing inks and influences cell adhesion, aggregation, and fusion. A new technique is used to measure this interaction when one of the bodies has colloidal dimensions. The potential energy profile of interactions between a 15-micrometer polystyrene sphere and a glass plate is determined by observing the distribution of separation distances (0.2 to 0.4 micrometer) that the particle samples by Brownian motion. Measurements of the speed with which the sphere is carried by linear shear flow along the wall are used to calculate separation distance. Although evidence for hydrodynamic lift is found, it is not included in the potential profile.