COLL 505 |
| Maria M. Santore, Department of Polymer Science, University of Massachusetts Amherst, 120 Governors Drive, Amherst, MA 01003 and Natalia Kozlova, Department of Polymer Science and Engineering, University of Massachusetts, 120 Governors Drive, Amherst, MA 01003. |
| We demonstrate how control of features at 10-nanometer length scales can tune adhesion at length scales that are much larger, on the order of microns. To demonstrate this principle, we employ an aqueous-based polymer-containing system in which negatively charged micron-sized colloids interact with planar surfaces presenting charged regions whose lateral heterogeneities are carefully controlled. We report adhesion rates of colloidal objects with these surfaces, and interpret the rate behavior in terms of energies and forces. We demonstrate the expected fast irreversible adhesion in the limit of pure attractions. However, interfaces with competing attractive and repulsive forces exhibit fast irreversible adhesion even when the integrated interfacial forces should be repulsive. As the density of repulsive features are further increased, the adhesion rate decreases, ultimately towards zero. We identify a critical nanometer-scale feature size for micron-scale adhesion, similar to the concept of pattern recognition, and show how this depends on the range of the attractions and repulsions. |
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“Smart” Polymers on Surfaces and Colloids
8:30 AM-11:30 AM, Thursday, April 1, 2004 Marriott -- Grand Ballroom J, Oral
Division of Colloid and Surface Chemistry |