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

• US 4,293,435 A
• Filed: 07/19/1979
• Issued: 10/06/1981
• Est. Priority Date: 07/20/1978
• Status: Expired due to Term

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Ringsdorf, Helmut, Finkelmann, Heino, Portugall, Michael
• Primary Examiner(s): Gron, Teddy S.
• Application Number:
  US06/058,943
• Time in Patent Office: 810 Days
• Field of Search: 252/299, 252/408, 73/356, 260/901, 526/320, 526/321, 526/325, 526/326, 428/1, 350/330, 350/352
• US Class Current: 252/299.01
• CPC Class Codes: B29C 71/00 After-treatment of articles without altering their shape; Apparatus therefor B29C44/56, B29C73/00 take precedence; surface shaping B29C59/00 ; for joined or sealed parts B29C66/03; after-treatment specially adapted for vulcanising tyres B29D30/0633
• CPC Class Codes: B29K 2105/0079 Liquid crystals
• CPC Class Codes: C07C 43/23 containing hydroxy or O-metal groups
• CPC Class Codes: C09K 19/12 at least two benzene rings directly linked, e.g. biphenyls
• CPC Class Codes: C09K 19/2007 the chain containing -COO- or -OCO- groups
• CPC Class Codes: C09K 19/2021 Compounds containing at least one asymmetric carbon atom
• CPC Class Codes: C09K 19/3852 Poly(meth)acrylate derivatives
• CPC Class Codes: C09K 19/3857 containing at least one asymmetric carbon atom
• CPC Class Codes: C09K 19/3866 containing steroid groups
• CPC Class Codes: C09K 2019/0448 the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate

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 R₁ is hydrogen or methyl, n is an integer from 1 to 6 and R₃ 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 λ_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.

Claims

1. A composition of matter exhibiting a liquid-crystalline cholesteric polymer phase consisting essentially of (1) at least one copolymer which contains (a) nematogenic units of the formula (I) ##STR74## where R₁ is hydrogen or methyl, n is an integer from 1 to 6 and R₃ is ##STR75## where Z is COO-- or OCO--, R₂ is --O(CH₂)_m H, --(CH₂)_m H or --COO--(CH₂)_m H, m being an integer from 1 to 6, and R₇ is hydrogen or R₂, and (b) chiral units of the formula (II) ##STR76## in which R₁ is hydrogen or methyl, n is an integer from 1 to 10 and R₄ is ##STR77## where Z is COO-- or OCO-- and R₅ is --CH═

N--R₆, --OR₆, --COOR₆, --CH═

CH--COOR₆ or --R₆, R₆ being alkyl or alkylaryl of 4 to 10 carbon atoms and having at least one asymmetric carbon atom or (2) a mixture of (a) a polymer having a nematic structure and containing units of the formula (I) and (b) a compound having a chiral structure.

2. The composition of matter of claim 1, wherein the liquid-crystalline cholesteric polymer phase is a copolymer which contains (a) nematogenic units of the formula (I) and (b) chiral units of the formula (II).

3. The composition of matter of claim 1, wherein the liquid-crystalline cholesteric polymer phase is a mixture of (a) a polymer having a nematic structure and containing units of the formula (I) and (b) a compound having a chiral structure.

4. The composition of matter of claim 3, wherein the compound having a chiral structure is a polymer with chiral units of the formula ##STR78## where R₁ is hydrogen or methyl, n is an integer from 1 to 10 and R₄ is ##STR79## where Z is COO-- or OCO-- and R₅ is --CH═

N--R₆, --OR₆, --COOR₆, --CH═

CH--COOR₆ or --R₆, R₆ being alkyl or alkylaryl of 4 to 10 carbon atoms and having at least one asymmetric carbon atom.

5. The composition of matter of claim 1, 2 or 3, wherein R₃ is ##STR80##

6. The composition of matter of claim 1, 2 or 3, wherein R₃ is ##STR81##

7. The composition of matter of claim 2, wherein R₄ is ##STR82##

8. The composition of matter of claim 4, wherein R₄ is ##STR83##

9. The composition of matter of claim 4, wherein R₄ is ##STR84##