Diffusion Studies of Model Thermotropic Polymers

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9321573 Ober Thermotropic main-chain polyethers will be prepared in both deuterated and undeuterated forms as model polymers for the investigation of diffusion behavior in liquid crystalline (LC) polymer melts. The target polymers will be prepared with a range of persistence lengths with sufficiently high molecular weights to form entangled melts in the isotropic state. The mesophase properties of these polymers will be evaluated. Forward recoil spectrometry (FRES) will be sued to determine the concentration profiles of these interdiffusing LC polymer chains. Small-angle neutron scattering will be used to determine the anisotropy ratio of the radius of gyration and the persistence length. Branched LC polymers will be prepared by endlinking chains. Collaborations with industrial scientists are planned, which will further characterize these thermotropic polymers using rheological measurements. The fundamental information derived from these studies will be useful for providing a better fundamental understanding of the melt properties of LC polymers. ***