Dissertation > Excellent graduate degree dissertation topics show

Study of the Synthesis and Mesomorphism of Liquid Crystalline Dimers and Liquid Crystalline Dendrimer

Author: WangNingZuo
Tutor: SunJianZhong
School: Zhejiang University
Course: Chemical Engineering
Keywords: Liquid crystal Liquid crystalline dimer Schiff-base Dendrimers Vinyl-terminated Nematic Smectic
CLC: O753.2
Type: Master's thesis
Year: 2012
Downloads: 22
Quote: 0
Read: Download Dissertation

Abstract


Liquid crystal materials have been widely applied in display and other special area for their outstanding thermoelectric properties. Great progress has been achieved in the research on the synthesis, performance and application of liquid crystal compounds. However, more excellent liquid crystal materials are required due to the further development of technology and the increasing civil demand. In this thesis, five novel liquid crystal compounds were synthesized. The relationship between molecular structure and liquid crystalline properties, especially the effect of aspect ratio and rigidity of the mesogen were carefully investigated.Firstly, using10-Undecen-l-ol as the initial reactant, a novel liquid crystal monomer was synthesized. And a novel Schiff-base type liquid crystalline dimer with two mesogens was obtained by reaction of the monomers and1,4-butanediamine. The structures of these compounds were characterized by FT-IR,1H NMR,13C NMR and ESI-MS. The liquid crystalline behavior of the compounds was characterized by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD). The typical nematic phase texture can be observed in monomer and dimer, and smectic C phase was also found in the dimer. Moreover, the dimeric compound exhibited wider mesophase temperature ranges and higher thermal stability.Secondly, in order to study the influence of aspect ratio and rigidity on the liquid crystal properties of liquid crystal monomer and dimer, a novel biphenyl-containing liquid crystal monomer and the corresponding Schiff-base type liquid crystalline dimer were prepared. Both of them showed typical nematic phase texture, wide mesophase temperature ranges and high thermal stability. In contrast to the formerly synthesized liquid crystal compounds, it is concluded that the rigidity of biphenyl structure does enlarge the mesomorphic ranges and enhance the thermal stability. However, motility and orientation of molecules are meanwhile confined.Finally, a novel liquid crystalline dendrimer was successfully synthesized by grafting the liquid crystal monomers to the terminals of the polypropylene imine (PPI) molecule. Typical layer structure of smectic A phase was observed by POM and XRD characterization. Microphase separation of different molecular parts of the liquid crystal dendrimer is responsible for the formation of more regular arrangement of liquid crystal molecules. More complicate mesophases may be obtained by tuning the structure of the dendritic core, dendrimer generation and terminally attached mesogenic units.

Related Dissertations

  1. Research of Wavefront Transformation Based on Liquid Crystal Spatial Light Modulator,TN761
  2. Synthesis and Properties of Novel Low Viscosity Difluorooxymethylene-Bridged Liquid Crystals Compounds,O753.2
  3. Synthesis and Asymmetric Catalytic Behaviors of Chiral Imine and Dimines Schiff Bases,O621.3
  4. Theoretical Analysis of the Circular Dichroism Spectra of Transition Metal Schiff-Base Complexes,O641.4
  5. The Study on the Tribological Property of Schiff Base Copper (Ⅱ) Complex in Different Basis Lubricating Oils,TE624.82
  6. Inorganic and inorganic - organic hybrid Zn -based catalysts and catalytic L- lactide ring-opening polymerization of L- polylactic acid applied research,O631.3
  7. 1,4 - bis (4 - amino-2 - (trifluoromethyl) phenoxy ) benzene -type Schiff base imide copolymer synthesis and characterization,O631.3
  8. Schiff base Synthesis, Characterization and Antibacterial Properties,O641.4
  9. One -dimensional photonic crystal tunable optical and magneto-optical properties of,O734
  10. Synthesis and Antibacterial Activities of Benzimidazole Multi-schiff Base Compounds,TQ463.5
  11. Synthesis and Properties of Liquid Crystalline Monomers and Crosslinked Polymers Containing Menthyl Groups,O753.2
  12. Synthesis and Properties of New Chiral Liquid Crystalline Monomers and Network Polymers,O753.2
  13. Synthesis and Characterization of Four Series of Main-chain Liquid Crystalline Inomoers Containing Carboxylic Ion,O631.3
  14. Synthesis and Characterization of 4,4’-2-amino Diphenyl Ether-type Schiff Base-imide Copolymers,O633.22
  15. Synthesis of Liquid Crystalline Polymers and Elastomers Containing Chiral Groups and Fluoronatied Units,O631.3
  16. Synthesis and Characterization of Several Liquid Crystal Monomers and Chiral Liquid Crystalline Polymers,O753.2
  17. Synthesis and Properties of the Kind "H" Liquid Crystals,O753.2
  18. Synthesis and Characteristic of Chiral Liquid Crystal Polymers Containing Donor-Acceptor Electrons and Monomers,O753.2
  19. A Class of Complexes of Rare-Earth-Metals with Schiff Base Ligands, Preparation and Application,O643.36
  20. Synthesis and Properties of New Difluorovinyl Tolane Liquid Crystal Comounds,O753.2
  21. Preparation and CO2 Adsorption Study of Microporous Polymer,O631.3

CLC: > Mathematical sciences and chemical > Crystallography > Amorphous and class crystalline > Class crystalline > Liquid crystal
© 2012 www.DissertationTopic.Net  Mobile