(3ds) Understanding the Impact of Reaction Parameters On Macromolecular Structure and Binding/Transport Properties of Recognitive Crosslinked Polymers

In this work, living/controlled polymerization (LRP) is compared to conventional free radical polymerization (FRP) in the creation of highly and weakly crosslinked imprinted poly(MAA-co-EGDMA) networks. It elucidates, for the first time, the effect of living/controlled polymerization on the chain level and begins to explain why the efficiency of the imprinting process is improved using living/controlled polymerization. Imprinted polymers produced via LRP exhibited significantly higher template affinity and capacity compared to polymers prepared using conventional methods. Use of LRP in the creation of highly crosslinked imprinted polymers resulted in a 4-fold increase in binding capacity without a decrease in affinity; while weakly crosslinked gels demonstrated a 3-fold increase in binding capacity at equivalent affinity when LRP was used. In addition, by adjusting the double bond conversion we can choose to increase either the capacity or the affinity in highly crosslinked imprinted polymers, thus, allowing the creation of imprinted polymers with tailorable binding parameters.

With the use of FRP in the creation of polymer chains, as the template/monomer ratio increased, the average molecular weight of the polymer chains decreased despite a slight increase in the double bond conversion. Thus, a larger number of shorter chains were formed. With LRP, the addition of chain transfer agent to the polymerization negated the retardation of kinetic chain length caused by the diffusional limitations presented by the macromer/template complexes. Reaction analysis revealed that propagation time was extended 3-fold in the formation of highly crosslinked polymers when LRP techniques were used. This delayed the transition to the diffusion-controlled stage of the reaction, which in turn led to the observed enhanced binding properties, decreased polydispersity in the chains, and a more homogeneous macromolecular architecture.