Liquid-crystalline polymer phase having a cholesteric structure, processes for its preparation and its use

US4293435A · kind A · utility

Assignee

• BASF SE

Inventors

• Michael Portugall · Monsheim, DE
• Heino Finkelmann · Clausthal-Zellerfeld, DE
• Helmut Ringsdorf · Mainz, DE

Key dates

• Filing date: Jul 19, 1979
• Grant date: Oct 6, 1981
• Expiry date: Jul 19, 1999

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09K2019/0448
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A liquid-crystalline polymer phase having an induced cholesteric structure comprises a component having a chiral structure and a component having a nematic structure and contains a polymer with nematogenic units of the formula ##STR1## wherein R.sub.1 is hydrogen or methyl, n is an integer from 1 to 6 and R.sub.3 represents specific structural elements containing at least two phenylene groups. Preferred is a copolymer comprising a component of the above formula and an additional chiral component of similar structure, prepared by copolymerization of the nematogenic monomer with the chiral monomer. The liquid-crystalline polymer phase permits variation of the wavelength of the reflected light .lambda..sub.R, and its cholesteric structure can be converted to the glassy polymer state and remains preserved in the solid state. Such liquid-crystalline polymer phases can be used in integrated optics, opto-electronics and information storage, e.g. for the manufacture of polarization filters or selective reflectors.