This thesis describes studies directed to the ring opening metathesis polymerisation of macromonomers and mesogenic monomers to produce graft copolymers and side chain liquid crystalline polymers respectively. The necessary background information relevant to the work described in this thesis is presented in chapter-1 and consists of four sections; namely, descriptions of metathesis polymerisation, anionic polymerisation, synthesis of graft copolymers and synthesis of side chain liquid crystalline polymers. The synthesis of the end capping reagent exo-5-norbomene-2- carbonyl chloride is described in chapter-2. The synthesis and characterisation of exo- 5-norbomene-2-poly(styrylcarboxylate) macromonomers by living anionic polymerisation is discussed in chapter-3. Chapter-4 reports the synthesis, characterisation and properties of graft copolymers prepared by ring opening metathesis polymerisation of exo-5-norbomene-2-poly(styrylcarboxylate) macromonomers. Chapters-5 describes the synthesis of the mesogenic monomer; (5)- (-)-2-methylbutyl-4-(4-(l 0-(3-cyclopentenylmethoxy) decyloxy) phenylcarbonyloxy) benzoate, suitable for ring opening metathesis polymerisation to produce side chain liquid crystalline polymer. The attempted synthesis of side chain liquid crystalline polymer by ring opening metathesis polymerisation of the mesogenic monomer; (5)-(- )-2-methylbutyl-4-(4-( 10-(3 -cyclopentenylmethoxy) decyloxy) phenylcarbonyloxy) benzoate is reported in chapter-6. Finally chapter-7 summarises the conclusions and makes some suggestions for future work.

Synthetic Laponite-clay particles with a platelet-like shape display strong gelation when dispersed in aqueous solutions because of their positively charged rims and negatively charged flat surfaces. In this thesis, my aim was to modify the surfaces of these clay particles such that we can both access their liquid crystalline (LC) discotic phase and further build transparent and mechanically resilient coatings with a 3D "brick-and-mortar" structure that is similar to that observed in natural mother of pearl (nacre). I first introduce a simple strategy that successfully suppresses Laponite's ageing phenomenon and enables the system's isotropic-to-LC phase transition. By grafting Laponite particle surfaces with comb-like polymers, poly (L-lysine)-g-poly (ethylene glycol) (PLL-PEG), I was able to screen negative surface charges and ensure steric stabilisation. Besides using long-chain polymers, I also coated the positively charged Laponite rims with small, barrel-shaped molecules cucurbit[7]uril (CB[7]). By carefully tuning the ratio between CB[7] and Laponite, the system experienced a macroscopic phase separation into a Laponite-poor suspension and a birefringent LC gel. Inspired by the hierarchical structure of nacre, here I also demonstrate a simple approach to fabricate polymer-clay hybrid films via a water-evaporation process. In this third method, Laponite platelets were bridged by natural abundant polymers (carboxymethyl cellulose) through hydrogen bonding. This hybrid material possesses high transparency, flexibility and an outstanding fire-retardant property. After Ca2+ ion-coordination of these cellulose-Laponite composite films, the interface between the polymers and clays was further strengthened, leading to enhanced mechanical properties along with improved thermal- and water-resistance. I also present that using Dextran as a depletant, sterically stabilised Laponite can access its liquid crystal phase under low clay concentration. Finally, I show that Laponite can be coated with various polymers (PEO, chitosan, sodium alginate) for the purpose of obtaining LC gels and hybrid films. I believe that our findings on surface-modification of clay particles can open new routes to large-scale and inexpensive production of bio-inspired functional materials.

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By using a special design of electrode pattern and the differential biased circuit, the gradient of the electric field distribution inside the liquid crystal sample cell can be achieved through the adjustment of driving voltage. The characteristics of positive or negative types of lens can be converted by changing the polarity of gradient within the sample cell which posses the homogeneous alignment. The liquid crystal lens with a variable focal length and the tunable types of focusing is demonstrated by utilizing the controllable distribution of electric field. This special design incorporating with the fabrication technology of TFT has a potential to develop a large scale of liquid crystal lens.

The liquid crystal display on the liquid crystal alignment is known to be influenced by the rubbing strength. In the thesis, in order to figure out the best condition for homeotropic alignment, we add the number of rubbing, which causes the increase of the rubbing strength. In the experiment, we discuss two parts. The first part discusses the relation between polarity and liquid crystal. The instrument used mainly is contact angle measurement system, which measures the contact angle between liquid and sample and calculates the polarity, the dispersion and the surface free energy. In the second part, we change the rubbing strength to analyze the influence of liquid crystal cell. Also, we use the electro-optical measurement to analyze the cell which is fabricated by different rubbing strength. It is at this part that we focus on analyzing the optical texture, transmittance, contract ratio, and sharpness. The sample¡¦s polarity rises as the rubbing strength increases. It is the influence of the liquid crystal pretitle angles that the polarity as well as the liquid crystal cell¡¦s optical property changes. Such changes could be seen in transmittance, contract ratio and sharpness

Currently , the STN-LCD with twist angle of 240 degree is the most popular operation mode . In this thesis , we utilize Photo-Sensitive spacer of TFT-LCD to substitute for the traditional spacer , and apply them in the above mentioned STN-LCD . The traditional spacer were used N2 air to spray on glass substrate by SUS tube . It make light leakage , decrease the transmittance , contrast ratio and aggregate spacer easily . When we pressure on glass and the phenomenon of migration has been found accordingly . It will influence quality of LCD . So we utilize Photo-Sensitive spacer to substitute for the traditional spacer in order to improve the defect . In this thesis , we fabricate different kind Photo-Sensitive spacer of size , shape and area ratio (Photo-Resist (NPS) from Everlight Chemical Industrial Corp) . We utilize Photo Lithography process to form the spacer thickness on insulation layer , and find the best type . In this experiment , the different characteristic of material between traditional spacer and Photo-Spacer were compared . And we utilize different process condition (pressure) and material(LC £Gnd) to discuss the relation . Finally , we proof the advantage of Photo-Spacer apply in STN-LCD .

Discotic liquid crystal is one kind of self-assembled material, liquid crystal with regular alignment could be applied to many kinds of organic electro-optical devices. This novel discotic liquid crystal polymer DLC-PAM, we used polyacrylamide(PAM) as main chain of the novel discotic liquid crystal polymer DLC-PAM and grafted the discotic liquid crystal monomer Acid-6 onto PAM by chemical synthesis. There were two parts in this study, first we investigated the electro-optical properties of DLC-PAM. Observation the aligned property of DLC-PAM during temperature variation utilizing polarizing optical microscope, DLC-PAM exhibited the columnar alignment. We observed hexagonal columns which DLC-PAM aligned by X-ray diffraction, it benefited the carrier transporting. The absorption spectrum of DLC-PAM presented an absorption peak at 409 nm certifying that DLC-PAM could absorb the visible light. We measured the HOMO potential of DLC-PAM which is 5.47eV by PESA. Form absorption spectrum we calculated the band-gap of DLC-PAM which was 2.55~2.82eV, and then we used the HOMO potential and the band-gap to calculate the LUMO potential of DLC-PAM to be 2.65~2.92eV. The second part in this study we applied DLC-PAM to the organic solar cell. Because of the energy level of DLC-PAM and the different device structure tests we realized that DLC-PAM was suitable to be hole transporting layer. The device structure we used was ITO/PEDOT:PSS/DLC-PAM/P3HT:PCBM/Al, DLC-PAM layer was added between the PEDOT:PSS layer and the active layer. The power conversion efficiencies proved that DLC-PAM layer which benefited hole transporting raising the power conversion efficiency of the solar cell. The power efficiency of the device added DLC-PAM layer raised 16.2% comparing with the standard device.

This study investigates the cholesteric grating based on a hybrid alignment. The experiment results reveal that the ordered stripe of the hybridly aligned cholesteric grating (H-fingerprint) only exists for the d/p ratio between 1.5 and 3, and the stripe orientation of the H-fingerprint is difficult to control due to the variation of the d/p ratio. Optical properties of the H-fingerprint are also investigated. The results show that the 1st order diffraction efficiency of the H-fingerprint is higher than the diffraction efficiency 2nd order, and its two switching times are about 1500ms and 500ms for the off-time and the on-time, respectively. The H-fingerprint with an anti-parallel rubbing process and the thermal effect are also investigated. The results reveal that the anti-parallel rubbing and the thermal effect can effectively control the stripe orientation of the H-fingerprint. The results greatly increase the possibility of applications for the H-fingerprint.

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 189-194).

Thesis (Ph.D.)--Kent State University, 2008. / Title from PDF t.p. (viewed Jan 5, 2010). Advisor: Philip J. Bos. Keywords: liquid crystal, smectic, display, ferroelectric. Includes bibliographical references (p. 190-194).