COLL 389 |
| Maria M. Santore, Department of Polymer Science, Department of Polymer Science, University of Massachusetts Amherst, 120 Governors Drive, Amherst, MA 01003 |
| This work examines the dynamics of cationic polymer chains adsorbed to a negative surface exclusively by electrostatic interactions. To probe chain mobility, we examine the desorption kinetics of chains into pure solvent, compared with the removal of originally adsorbed chains by like chains in free solution, called “self exchange”. Typically desorption is slower than self exchange because the energy cost of desorption is the unbinding of all segment-surface contacts at once. By comparison, self exchange has a lower energy cost since segments of the adsorbing chain may replace those of the preadsorbed chain a few at a time. Here, we systematically vary the number of charged segments per chain and the ionic strength of the solution, essentially varying the number and strength of segment-surface contacts. In this contact number-contact energy 2-dimensional space, we map out kinetic regimes where self exchange and desorption display different relative timescales. |
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Symposium in Memory of Arthur W. Adamson
8:30 AM-12:10 PM, Wednesday, March 31, 2004 Marriott -- Orange County 4, Oral
Division of Colloid and Surface Chemistry |