Fast switching polysiloxane ferroelectric liquid crystals
US5138010A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 1990 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Jun 25, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K19/408
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
New ferroelectric liquid crystal (FLC) materials comprising linear and cyclic polysiloxanes are described. The FLCs exhibit high polarization and fast switching speeds. The disclosed polysiloxanes are derivitized with mesogenic groups which induce high polarization, specifically chiral nonracemic epoxide mesogens, having phenylbenzoate, reverse phenylbenzoate and biphenyl cores. These epoxy polysiloxanes are chemically stable over extended periods. Further, the epoxides can be crosslinked to produce FLC elastomers and like materials having optoelectronic applications. It was found that in the pure polysiloxanes, the smectic layers align along the rubbing direction of an anisotropic surface on contact with that surface. An unexpected alignment transition is observed as a function of polysiloxane concentration in polysiloxane/LC monomer mixtures with smectic layers orienting along the rubbing direction at high polymer concentrations and, typical of low molecular weight liquid crystals, normal to the rubbing direction at low polymer concentrations. A method for alignment of FLC polysiloxanes is described. The aligned polysiloxane FLCs and FLC mixtures exhibit high contrast electro opt…
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