Skip to main content
Main Menu
Utility Menu
Search
HARVARD.EDU
Contact
News
Search
Mission
Research
Publications
Team
Join Our Team
HOME
/
May 2001: Nanoparticle Halos: A New Colloid Stabilization Mechanism
« Back to gallery
Item 31 of 32
« Previous
|
Next »
A new mechanism for regulating the stability of colloidal particles has been discovered. Negligibly charged colloidal microspheres, which flocculate when suspended alone in aqueous solution, undergo a remarkable stabilizing transition upon the addition of a critical volume fraction of highly charged nanoparticle species. Zeta potential analysis revealed that these microspheres exhibited an effective charge buildup in the presence of such species. Scanning angle reflectometry measurements indicated, however, that these nanoparticle species did not adsorb on the microspheres under the experimental conditions of interest. It is therefore proposed that highly charged nanoparticles segregate to regions near negligibly charged microspheres because of their repulsive Coulombic interactions in solution. This type of nanoparticle haloing provides a previously unreported method for tailoring the behavior of complex fluids.