Dopant-Enhanced Vertical Alignment of Negative Liquid Crystals

Dopant-Enhanced Vertical Alignment of Negative Liquid Crystals

A simple method for achieving high-contrast vertical alignment of high birefringence (Dn 0.28) negative dielectric anisotropic liquid crystal mixture using buffed polyimide substrates is demonstrated. By doping a positive, or non-polar dielectric anisotropic compound or mixture to the laterally difluorinated tolane liquid crystal host, an excellent vertical alignment was obtained. This alignmen...

Homeotropic alignment of nematic liquid crystals with negative dielectric anisotropy

We report here uniform and defect-free homeotropic alignment of nematic liquid crystal having negative dielectric anisotropy (Deo0) on cleaned substrates, which can be changed to bright state (homogeneous alignment) by applying an electric field. However, non-uniformity in the bright state would not be desirable for display devices. Therefore, silane treated and gently rubbed substrates have be...

Substrate-induced bulk alignment of liquid crystals.

A helical naphthopyran dopant for photoresponsive cholesteric liquid crystals.

The first photoresponsive cholesteric liquid crystal comprising a photoisomerizable helical naphthopyran derivative dopant and a nematic liquid crystal is reported. An unprecedented helical twisting power switching ratio of over 90% allowed us to demonstrate multi-cycle rotational motion of micro-objects by UV light irradiation.

Photo-Induced Vertical Alignment of Liquid Crystals via In Situ Polymerization Initiated by Polyimide Containing Benzophenone

Vertical alignment of liquid crystal (LC) was achieved in an easy and effective way: in situ photopolymerization of dodecyl acrylate (DA) monomers initiated by polyimide based on 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and 3,3′-dimethyl-4,4′-diaminodiphenyl methane (BTDA-DMMDA PI). The alignment behavior and alignment stabilities were characterized by a polarizing optical microscope (...