Control of liquid crystal alignment using surface-localized low-density polymer networks and its applications to electro-optical devices
| Autor: | Vassili Sergan, Lu Lu, Phillip J. Bos, Ekaterina V. Sergan, Raul Herrera, Tatiana A. Sergan |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Fabrication
Materials science 02 engineering and technology 01 natural sciences Liquid crystal Phase (matter) 0103 physical sciences Materials Chemistry Physical and Theoretical Chemistry Diffraction grating Spectroscopy 010302 applied physics chemistry.chemical_classification business.industry Polymer 021001 nanoscience & nanotechnology Condensed Matter Physics Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials chemistry Polymerization Optoelectronics 0210 nano-technology business Layer (electronics) Voltage |
| Zdroj: | Journal of Molecular Liquids. 267:131-137 |
| ISSN: | 0167-7322 |
| DOI: | 10.1016/j.molliq.2018.02.125 |
| Popis: | We developed an alignment method for control of the polar pretilt angle at the boundaries of a liquid crystal (LC) layer in a continuous range 2–90° by introducing a low-density polymer network. The network was formed as a result of the electric field-induced segregation of a photo-reactive monomer added in concentrations of 0.5–1% to the LC host and subsequent in-situ UV-light-induced polymerization. LC director was “frozen” within a less than a micron-thick layer in the vicinity of the cell substrates at high average tilt angles anchoring the LC in the bulk similarly to a high-pretilt alignment layer. The resultant pretilt angle was determined by the voltage applied before and during polymerization and the duration of voltage application before UV-light exposure. The desired pretilt angle could be set over a small area of a sample which allowed for the fabrication of LC devices with spatially variable optical retardation. Using this method, we fabricated high-pretilt splay and bend LC cells, optically recorded converging lenses and bi-prisms with electrically controlled optical characteristics, and phase diffraction gratings with resolution better than 50 lines/mm. |
| Databáze: | OpenAIRE |
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