Currently the best method for characterizing the microstructures of synthetic polymer is high resolution 13C-NMR observations of their solutions, can be sensitive to microstructures encompassing 1 or 2nm of the polymer backbone. However, due to the short-range structural sensitivity of NMR and other spectro-scopic probes, they can only identify and quantify local micro-structural features, but are unable to locate them along or among polymer chains. We need only look at the one-to-one correspondence between the primary structures and biological functions of proteins to recognize a similar need to characterize complete individual chain architectures, i.e., the macrostructures, of synthetic polymers. The Kerr-Effect, or birefringence electrically induced in dilute polymer solutions by the magnitudes and directions of overall macroscopic polymer chain dipole moments and anisotropic polarizability tensors when averaged over all of their myriad conformations, is highly sensitive to their overall macrostructures. Potential complete chain macrostructures are, however, virtually innumerable, so we need to be able to estimate the Kerr constants resulting from different locations of the short-range microstructures obtained by 13C-NMR. Agreement between observed and estimated Kerr-Effects can then lead to the elucidation of polymer macrostructures. Fortunately, Flory taught us how to estimate the conformationally averaged molar Kerr constants of polymers in “Statistical Mechanics of Chain Molecules”

Characterizing the overall molecular architectures of synthetic polymers requires Flory’s Statistical Mechanics of Chain Molecules

2019 Fall National Meeting

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