Reactions at polymer interfaces: Transitions from chemical to diffusion-control and mixed order kinetics
Department of Chemical Engineering, Columbia University
500 West 120th St., New York, NY 10027, USA
2 Department of Physics, Columbia University 538 West 120th St., New York, NY 10027, USA
Accepted: 21 December 1998
We study reactions between end-functionalized chains at a polymer-polymer interface. For small chemical reactivities (the typical case) the number of diblocks formed, , obeys 2nd-order chemically controlled kinetics, , until interfacial saturation. For high reactivities (e.g., radicals) a transition occurs at short times to 2nd-order diffusion-controlled kinetics, with for unentangled chains while and regimes occur for entangled chains. Long-time kinetics are 1st order and controlled by diffusion of the more dilute species to the interface: for unentangled cases, while and regimes arise for entangled systems. The final 1st-order regime is governed by center-of-gravity diffusion, .
PACS: 82.35.+t – Polymer reactions and polymerization / 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion / 68.10.-m – Fluid surfaces and fluid-fluid interfaces
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