As protein tertiary and quaternary structures and their resulting functions are determined by their primary sequence of amino acids, so too are the behaviors and properties of synthetic polymers critically dependent on their macrostructures. Relevant structure-property relations developed for polymer materials must also be based on their macrostructures, i.e., the types, quantities, and locations of their constituent microstructures. NMR, usually high field, high resolution 13C-NMR observed in solution, has repeatedly been demonstrated to be the premier experimental means for elucidating the constituent micro-structural elements present in polymers. Like most spectroscopies, NMR is generally only sensitive to relatively local, short-range microstructures, which do not extend beyond 1 or 2 nm along polymer backbones. To determine polymer macrostructures requires a probe whose consequent observable also depends on the complete macrostructure. We believe that observation of the birefringence produced by application of a strong electric field to dilute solutions of polymers, i.e.,their electrical birefringence or Kerr effect, provides a means to characterize the macrostructures of polymers. The contribution made by a polymer solute to the solution Kerr effect depends on and is highly sensitive to both the magnitude and orientation of its overall dipole moment and polarizability tensor. As such, and for the first time, we are able to demonstrate its use to locate along the polymer backbone those short-range microstructural elements that are identifiable by NMR, thus enabling the complete characterization of a polymer chain's macrostructure.                                                                   [ figure1]

Coupling the Kerr effect and NMR to determine polymer macrostructures

247th National Meeting (2014)

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