Main-Chain Ferroelectric Liquid Crystal Polymers for Electronic Nonlinear Optics Applications
Source abstract
Abstract
We report the synthesis of organic polymer optical fibers with the following interesting supermolecular stereochemistry: 1) A thermodynamically stable macroscopic polar axis oriented approximately normal to the fiber axis; and 2) A nonlinear optical (NLO) chromophore oriented along the polar axis. Such a polymer fiber has been created using a main-chain ferroelectric liquid crystal polymer (FLCP) frozen in the glassy state at room temperature. The material is composed of “side-by-side twin” mesogens wherein the DR-1 NLO chromophore is oriented normal to the director. The polymer, which possesses excellent liquid crystal and glass transition temperatures for the present study, was prepared by acyclic diene metathesis polymerization of a liquid crystal diene. Details of the layer and director structure in the FLCP glasses are under investigation.
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Research context
OpenAlex topics: Liquid Crystal Research Advancements · Photonic and Optical Devices · Semiconductor Lasers and Optical Devices
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Affiliations
Department of Chemistry and Biochemistry, and the Ferroelectric Liquid Crystal Materials Research Center, University of Colorado
Department of Physics, and the Ferroelectric Liquid Crystal Materials Research Center, University of Colorado
References (9)
Show source-provided references
1. 10.1039/b102732h10.1039/b102732h ↗
2. 10.1021/ja952387p10.1021/ja952387p ↗
3. 10.1021/ja953779z10.1021/ja953779z ↗
4. Keller , P. , Shao , R. , Walba , D. M. , Brunet , M. , Chien , L.-C. , Petschek , R. G. , Bai , F. , Sierra , T. , Omenat , A. , Barberá , J. and Serrano , J. L. 1996 . Liq. Cryst. Polym. Mater. Sci. Eng. Adv. Mater. , 8 : 752 – 756 . c)
5. 10.1351/pac19997111211710.1351/pac199971112117 ↗
6. All new compounds in the route leading to diene 6 and the polymer showed consistent 1H and 13C NMR spectra. Mesogen 6 and most intermediates gave satisfactory combustion analyses. The structural assignments are quite secure
7. Assignment of the dimer structure, as a mixture of constitutional isomers, was made based upon 1H and 13C NMR spectrometry. End-group analysis by 1H NMR was nicely indicative of dimer
8. In measuring the mesogen length of monomer 6 , a fully extended conformation was generated as an MM2 minimum. The mesogen length l was taken to be the distance between terminal olefinic hydrogen atoms plus twice the covalent radius of hydrogen; l = 37.9 Å. The maximum value of the layer spacing d observed for diene 6 was d = 28.69 Å. The “X-ray tilt” in the smectic C* phase, defined as arccos (d/l) = 40.8°. The “mesogen length” in the polymer was taken as the distance between the mid-points of the terminal double bonds in the fully extended conformation; l = 34.6 Å. The observed layer spacing d = 26.98 Å for the polymer gives a calculated tilt of 38.8° for the polymer smectic C* phase. The mesogen length in the dimer was taken as the distance between either of the above mentioned mid-points and the opposite terminal olefinic hydrogen atom plus one covalent hydrogen radius; l = 36.2 Å. The observed layer spacing of d = 27.67 Å for the dimer gives a calculated tilt of 40.1 Å for the dimer. Due to the low throughput and contrast obtained in SSFLC cells prepared using these materials, reliable optical tilt angles could not be obtained
9. 10.1080/1542140920804823810.1080/15421409208048238 ↗