(751b) Nanoconfined Polymerization Reaction Kinetics and Thermodynamics

The behavior of materials confined at the nanoscale has been of considerable interest over the past several decades.  Recent work in our laboratory has focused on the influence of nanoconfinement on polymerization kinetics, as well as the effects of synthesis under nanoconfinement on polymer properties.  In the case of step-growth polymerization of cyanate esters and free radical polymerization of methyl methacrylate, we find enhanced reactivity with decreasing nanopore size.  On the other hand, in the ring-opening polymerization of dicyclopentadiene, we find reduced reactivity and the presence of a side reaction not present in the bulk system.  In sulfur polymerization, the ring/chain equilibrium has also been found by other researchers to shift towards less polymer in confinement.  All of the results can generally be explained by competition between changes in local packing and diffusivity under confinement coupled with entropic and surface effects.  In this presentation, we detail the ability to describe nanoconfined reaction kientics using models that incorporate changes in diffusivity and entropy upon nanoconfinement using scaling from the literature.