Polymeric liquid crystals

• US 4,637,896 A
• Filed: 10/12/1984
• Issued: 01/20/1987
• Est. Priority Date: 12/15/1982
• Status: Expired due to Term

• Current Assignee: Advantage Technology, Inc. (Applied Holographics PLC)
• Original Assignee: Armstrong World Industries Incorporated
• Inventors: Shannon, Paul J.
• Primary Examiner(s): Gron, Teddy S.
• Assistant Examiner(s): Thomas, Jack
• Application Number:
  US06/660,038
• Time in Patent Office: 830 Days
• Field of Search: 252/299.01, 252/299.7, 260/397, 260/397.1, 260/397.2, 428/1, 526/284
• US Class Current: 252/299.7
• CPC Class Codes: C09K 19/36 Steroidal liquid crystal compounds
• CPC Class Codes: C09K 2019/0448 the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate
• CPC Class Codes: Y10T 428/31935 Ester, halide or nitrile of addition polymer

Abstract

The present invention concerns novel cholesteric liquid crystalline monomers and combinations thereof with materials that will support formation of a mixture which demonstrates cholesteric liquid crystalline properties. These materials may be formed as coatings, heated or cooled to a desired temperature to cause the cholesteric coating to exhibit a desired optical response, and photopolymerized to essentially fix the optical characteristics of the resulting polymer.

Claims

1. A polymeric coating exhibiting a fixed cholesteric optical response, said coating being obtained by photopolymerizing a composition comprising

a photopolymerizable monomer having the structure:

##STR7## where R₁ =H or CH₃, A=--R₂ --, --R₃ O--, or --R₄ O--, R₂ =an alkylene chain having from 3-14 methylene or lower alkyl-substituted methylene groups, R₃ =an alkylene chain having from 2-14 methylene or lower alkyl-substituted methylene groups, R₄ =an alkylene ether, diether or triether having a total of from 3-14 carbon atoms in the alkylene moieties, provided that the terminal alkylene moiety adjacent the carbonate moiety comprises not less than two carbon atoms, and y=0 or 1; and

a suitable photoinitiator, said composition having exhibited cholesteric liquid crystalline properties at the time photopolymerization occurred.

2. The invention as set forth in claim 1 hereof wherein said composition comprises a second material which facilitate to permit formation of a coating that exhibits cholesteric liquid crystalline properties.

3. The invention as set forth in claim 2 hereof wherein said second material is a compound having the structure of Formula I.

4. The invention as set forth in claim 2 hereof wherein said second material is a photopolymerizable material having a structure which is different from that of Formula I.

5. The invention as set forth in claim 2 hereof wherein said second material is a mesogenic material having a structure which is different from that of Formula I.

6. The invention as set forth in claim 5 hereof wherein said second material comprises a photopolymerizable moiety.

7. The invention as set forth in claim 2 hereof wherein said composition comprises a cross-linking agent.

8. The invention as set forth in claim 2 hereof wherein at least one of the alkylene moieties of R₄ is lower-alkyl substituted.

9. The invention as set forth in claim 2 hereof wherein said coating selectively reflects visible light.

10. The invention as set forth in claim 9 hereof wherein said coating selectively reflects visible light to provide multiple color effects.

11. The invention as set forth in claim 2 hereof wherein said coating selectively reflects ultraviolet light.

12. The invention as set forth in claim 2 hereof wherein said coating selectively reflects infrared light.

13. The invention as set forth in claim 2 hereof wherein said composition is substantially uniformly mechanically aligned to provide a cholesteric planar texture.

14. The invention as set forth in claim 2 hereof wherein said composition is selectively mechanically aligned to provide a cholesteric planar texture in selected areas.

15. The invention as set forth in claim 2 hereof wherein said coating comprises a homeotropic texture.

16. The invention as set forth in claim 2 hereof wherein said coating comprises a focalconic texture.