Liquid crystal materials
AssigneeThe Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
InventorsGeorge W. Gray, Damien G. McDonnell
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Abstract
Liquid crystal materials are provided which are esters having the general formula: ##STR1## where n has the value 1, 2 or 3 and R is a normal or branched chain alkyl containing up to ten carbon atoms and preferably four to ten carbon atoms. These materials display a cholesteric mesophase and also a chiral smectic C mesophase underlying the cholesteric mesophase. Both of these mesophases are thermochromic.
Claims19
A liquid crystal material containing a plurality of compounds at least one of which is a cholesteric liquid crystal compound having a molecular helical pitch length of the order of 0.2 .mu.m, wherein the improvement comprises the said cholesteric compound being an ester having the formula ##STR18## wherein R.sup.1 is a branched alkyl group having a chiral center and R is an alkyl group having 1 to 10 carbon atoms with the proviso that the racemates of said at least one cholesteric ester compound are excluded from the liquid crystal material.
Dependencies are inferred from the claim text.