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Liquid crystalline polymers with complex architectures

Kawasumi, Masaya
http://rave.ohiolink.edu/etdc/view?acc_num=case1060626491

Abstract Details

1993, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science.
Novel classes of thermotropic liquid crystalline polyethers with linear, cyclic and dendritic architectures are described. All the mesogenic units have the same basic skeleton based on conformational isomerism, i.e., 1-(4-hydroxy-4′-biphenyl)-2-(4-hydroxyphenyl)substituted or nonsubstituted alkanes which were designed according to a simple thermodynamic scheme so that resulting polyethers can exhibit an enantiotropic mesophase.The synthesis and characterization of thermotropic linear polyethers based on 1-(4-hydroxy-4′-biphenyl)-2-(4-hydroxyphenyl)butane (TPB) and α,ω-dibromoalkanes containing X methylenic units (TPB-X, X = 4-20) are described. Most of TPB-X exhibit an enantiotropic nematic mesophase as predicted from the simple thermodynamic scheme. The linear polyethers based on 1-(4-hydroxy-4′-biphenyl)-2-(4-hydroxyphenyl)decane (TPD) and α,ω-dibromoalkanes containing X methylenic units (TPD-X, X = 6-10) were synthesized and the thermal behavior was compared with that of TPB-X. Most of cyclic oligomers exhibit a nematic mesophase. The effect of the ring size and spacer length on the phase behavior was discussed. The chiral linear and cyclic polyethers based on chiral (R)-TPB* and α,ω-dibromoalkanes containing X methylenic units (linear polyethers, TPB*-X, X = 10, 12, 14, 16; cyclic polyethers, TPB*-X(c), X = 10) were synthesized and characterized. The effect of chirality of the mesogenic unit on the phase behavior was studied. The synthesis and characterization of the first thermotropic dendrimers based on 10-bromo-1-(4-hydroxy-4′- biphenyl)-2-(4-hydroxyphenyl)decane (TPD-b) and 6-bromo-1-(4-hydroxy-4′-biphenyl)-2 -(4-hydroxyphenyl)hexane (TPH-b) are described. The dedrimers were synthesized by the homopolymerization of TPD-b or TPH-b followed by the alkylation with an alkyl bromide or benzyl chloride. Some of the resulting dendrimers exhibit an enantiotropic nematic mesophase. The effect of the chain end groups on their phase behavior was studied The molecular weight effect on the thermal behavior was studied with synthesized oligomers and fractionated linear TPB-10 polyethers with number average molecular weights from monomer to about 57,200. The synthesis and characterization of the fi rst thermotropic cyclic main chain oligomers based on TPB and α,ω-dibromoalkanes containing X methylenic units (TPB-X(c), X = 4-14, 18) are presented. The cyclic oligomers were separated and were characterized by 1H-NMR, GPC, and DSC.
Virgil Percec (Advisor)
379 p.
Chemistry, Organic
Liquid crystalline polymers; Complex architectures

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Citations

  • Kawasumi, M. (1993). Liquid crystalline polymers with complex architectures [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1060626491

    APA Style (7th edition)

  • Kawasumi, Masaya. Liquid crystalline polymers with complex architectures. 1993. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1060626491.

    MLA Style (8th edition)

  • Kawasumi, Masaya. "Liquid crystalline polymers with complex architectures." Doctoral dissertation, Case Western Reserve University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1060626491

    Chicago Manual of Style (17th edition)

case1060626491
457
© 1993, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.