Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


case1055364243.pdf (6.23 MB)

ETD Abstract Container

Abstract Header

Liquid crystal polymers containing crown ether ligands

Rodenhouse, Randall Alan
http://rave.ohiolink.edu/etdc/view?acc_num=case1055364243

Abstract Details

1991, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science.
This dissertation is concerned with the synthesis and characterization of the first examples of thermotropic main chain and side chain liquid crystalline polymers containing crown ether ligands. The main chain polymers are polyethers and copolyethers based on bis(8-bromooctyl)dibenzo-18-crown-6, α,ω-dibromoalkanes with 4,4′-dihydroxy-α-methylstilbene and/or trans-1,4-bis(hydroxyphenylethane)cyclohexane. The polyethers based on 4,4′-dihydroxy-α-methylstilbene and bis(8-bromooctyl)dibenzo-18-crown-6 and those based on trans-1,4-bis(hydroxyphenylethane)cyclohexane and bis(8-bromooctyl)dibenzo-18-crown-6 are both crystalline. Copolymerization with α,ω-dibromoalkanes lead to copolymers exhibiting monotropic nematic mesophases. Extrapolation of this data demonstrates that the homopolymers based on 4,4′-dihydroxy-α-methylstilbene with bis(8-bromooctyl)dibenzo-18-crown-6 and trans-1,4-bis(hydroxyphenyl-ethane)cyclohexane with bis(8-bromooctyl)dibenzo-18-crown-6 exhibit a virtual monotropic nematic mesophase. Two polymer architectures were investigated for the design of side chain liquid crystalline polymers containing crown ethers. The first refers to the insertion of the crown ether within the structure of the mesogenic side group while the second refers to insertion within the structure of the polymer backbone. In the former approach, polysiloxanes and polymethacrylates containing 4-(ω-alkan-1-yloxy)-4′-(4′ -carboxybenzo-15-crown-5)biphenyl side groups were synthesized and found to display enantiotropic nematic and smectic mesophases. Additionally, side chain liquid crystalline polymethacrylates containing mesogenic units based on diarylacetylene and benzo-15-crown-5 have been synthesized in order to further elucidate the structure-property relationships. The polymethacrylate containing 1,4-disubstituted phenylene structural units exhibited only a crystalline phase. However, polymers containing 2,6-disubstituted naphthalene structural units displayed monotropic nematic mesophases. Furthermore, incorporation of a lateral substituent transformed this monotropic mesophase into an enantiotropic mesophase. The polymethacrylate containing a substituted diphenylacetylene connected to benzo-15-crown-5 by a carboxy interconnecting unit displayed on enantiotropic nematic and smectic mesophase. The second approach to the synthesis of side chain liquid crystalline polymers includes incorporation of crown ether ligands within the polymer backbone. This was accomplished by cationic cyclocopolymerization of 1,2-bis(2-ethenyloxyethoxy)benzene with mesogenic vinyl ethers. However, mesomorphic properties were obtained only for copolymer compositions rich in mesogenic vinyl ethers and therefore contain low concentrations of crown ether ligands within the polymer backbone. This problem was overcome by the synthesis of a 1,2-bis(2-ethenyloxyethoxy)benzene derivative containing a mesogenic side group. Cationic cyclopolymerization of this system led to liquid crystalline polymers containing a crown ether and a mesogenic group within each structural unit of the polymer.
Virgil Percec (Advisor)
238 p.
Liquid crystal polymers crown ether ligands

Recommended Citations

Citations

  • Rodenhouse, R. A. (1991). Liquid crystal polymers containing crown ether ligands [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1055364243

    APA Style (7th edition)

  • Rodenhouse, Randall. Liquid crystal polymers containing crown ether ligands. 1991. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1055364243.

    MLA Style (8th edition)

  • Rodenhouse, Randall. "Liquid crystal polymers containing crown ether ligands." Doctoral dissertation, Case Western Reserve University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055364243

    Chicago Manual of Style (17th edition)

case1055364243
653
© 1991, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.