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| DC Field | Value | Language |
|---|---|---|
| dc.contributor.author | Chauhan, Garima | - |
| dc.date.accessioned | 2025-12-16T11:01:41Z | - |
| dc.date.available | 2025-12-16T11:01:41Z | - |
| dc.date.issued | 2024 | - |
| dc.identifier.uri | http://localhost/xmlui/handle/1/66 | - |
| dc.description.abstract | Dispersed liquid crystal consisting of polymers and liquid crystals offers a foundation for designing novel materials with adjustable characteristics, enabling their utilization across diverse technological applications. The ability to manage and adjust the orientation of liquid crystals within a polymer matrix is a critical element in developing materials that can respond to external stimuli, rendering them well-suited for a broad spectrum of applications in the realms of optics and electronics. Efforts have been invested by incorporating nanomaterials into polymer-stabilized liquid crystal systems to achieve favorable conditions in devices such as reducing threshold voltage, enhancing contrast ratio, increasing flexibility, broadening viewing angles, and optimizing response times. In the present thesis, the polymer stabilized liquid crystal composites are prepared and investigated the role of different types of nanomaterials (TiO2 NPs, CdSe QDs) on the physical properties of host material. Further, Morphological behaviour of LC confined in polymer matrix, dielectric, and electro-optical studies have been investigated in the composites. To achieve the outlined goals, the planned study is structured into seven chapters. These encompass the introduction, a review of relevant literature, details on experimental techniques along with the methodology employed, a presentation and discussion of results, and conclusions, and a final section focusing on future prospects. Chapter 1: This chapter initiates with a concise overview of the historical evolution and presence of LCs, as well as their fundamental attributes and distinctive properties. A comprehensive address is provided on the diverse categories of LCs, encompassing both lyotropic and thermotropic variants. Calamitic LCs is primarily discussed in the current thesis. The molecular arrangement of nematic, cholesteric and ferroelectric LCs are also mentioned. LCs polymer-based system: polymer stabilized LCs (PSLCs) and polymer dispersed LCs (PDLCs) are also described. The preparation methods and working principle of PSLCs are also discussed in detail. Chapter 2: This chapter describes the development of the PSLCs and offers a summary of the efforts made by the researchers to identify its applications. The PSLCs with different kinds of LCs (CLCs and FLC) are reviewed from diverse perspectives. The literature and recent advances in PSLCs and NMs-PSLCs composites are outlined. The impact of different types of NMs on the various features of PSLCs are disclosed. The effects of NMs having various shape, size, and concentration on PSLCs properties are discussed. Chapter 3: In this chapter, the details of used materials (LCs, NMs, polymer, and chiral dopants), along with their physical parameters and chemical compositions are presented. The preparation method of PSLCs and NMs doped PSLCs are described in the flowchart. The methodology used for LCs cell preparation is also included. The chapter also contains the explanation of different experimental tools and methods necessary for investigating the textural characteristics, phase transitions, electro￾optical responses, dielectric behavior, and photoluminescent properties. Chapter 4: This chapter encloses the effect of polymer concentration on the physical properties of ferroelectric liquid crystal. The different concentrations of polymer (1,3 and 5 wt.%) were incorporated into ferroelectric liquid crystal. Dielectric and electro￾optical studies are analyzed of all the polymer stabilized ferroelectric liquid crystal. The effect of voltage on spontaneous polarization, switching time and rotational viscosity are represented in this chapter. Anchoring energy and conductivity has also been examined. The temperature and voltage dependent dielectric studies has been analyzed for all the samples. The effect of concentration of polymer on the photoluminescence spectra of ferroelectric liquid crystal are also analyzed. The interaction mechanism between FLC molecules and polymer is also explained in the current chapter. Chapter 5: In the chapter, TiO2 nanoparticles dispersed polymer-stabilized cholesteric liquid crystal composites are prepared and studied. The investigation involves exploring the impact of varying concentrations of TiO2 NPs doping into PSCLCs on phases, molecular configurations, as well as the dielectric, electro-optic, and photoluminescent characteristics. The voltage and temperature dependent morphological studies revealed a considerable effect of TiO2 NPs on liquid crystal molecules. The photoluminescence intensity increased with TiO2 NPs; however, emission wavelength did not change. The study envisioned an easy way to utilized TiO2 NPs to fabricate electro-optical devices with minimal energy usage. Chapter 6: The present chapter discusses the fabrication of polymer stabilized cholesteric liquid crystal. Herein, different concentrations of cadmium selenide quantum dots (0.1 and 0.25 wt.%) were incorporated into polymer stabilized xxiii cholesteric liquid crystal. The phase-dependent and morphological studies were investigated for all the samples. The effect of bias voltage on the texture of CdSe quantum dot doped polymer stabilized cholesteric were analyzed. The dielectric study revealed that the dispersion of QDs affect the permittivity, dielectric loss and conductivity of QDs doped samples. Dielectric anisotropy and splay elastic constant are also analyzed. The variation in electro-optical parameters were also analyzed for QDs doped system. The result indicates that incorporation of QDs into polymer stabilized cholesteric liquid crystal provides an alignment to the liquid crystal molecules at low electrical energy. Chapter 7: The chapter summarizes the effect of polymer and nanomaterials on the properties of liquid crystal and its composites. On the basis of work done, the future scope of the presented work is also highlighted. | en_US |
| dc.language.iso | en | en_US |
| dc.publisher | NIT Jalandhar | en_US |
| dc.subject | Department of Physics | en_US |
| dc.title | Preparation and characterization of polymer stabilized liquid crystal composites | en_US |
| dc.type | Thesis | en_US |
| Appears in Collections: | PHD - Thesis | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| Thesis Garima Chauhan.pdf | 9.72 MB | Adobe PDF |  View/Open |
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