In situ control of surface molecular order in liquid crystals using a localised polymer network and its application to electro-optical devices
| Autor: | Lu Lu, Phillip J. Bos, Vassili Sergan, Raul Herrera, Tatiana A. Sergan, Ekaterina V. Sergan |
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| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | Liquid Crystals. 40:72-82 |
| ISSN: | 1366-5855 0267-8292 |
| DOI: | 10.1080/02678292.2012.733036 |
| Popis: | A liquid crystal (LC) alignment technique has been developed that allows local control of the polar pretilt angle over the range of 0–90°. This was achieved through the formation of a polymer network localised in the vicinity of the LC cell substrates. The network was formed as a result of in situ UV-induced polymerisation of a photo-reactive monomer added at concentrations of 0.5–1%. Localisation of the polymer network at the LC–substrate boundary was achieved by the application of a high voltage before polymerisation. The resultant pretilt angle was determined by the voltage applied during the polymerisation and/or the duration of the voltage application before the polymerisation step. The desired pretilt angle could be set over a small area of the sample, which allows the fabrication of LC devices with spatially variable optical retardation. Using this method we fabricated a converging lens, a bi-prism, and a phase diffraction grating with resolution greater than 50 lines mm−1. |
| Databáze: | OpenAIRE |
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