Abstract:
Increasing dosages of X-ray radiation progressively lower the color-play range of cholesteric-phase liquid-crystal materials. The effect is enhanced when an effective amount of an iodinecontaining compound is used in the liquid-crystal material. Novel iodine-containing compounds are described, and articles are disclosed that give direct reading indication of the dosage of Xray radiation that they have received, without need for a separate development operation.
Abstract:
Electromagnetic radiation in the frequency range of 1012.5 to 1017 cycles per second is detected, using a cholesteric liquidcrystal material to which there has been added, in the case of radiation of lower frequency, a suitable oil or oil-soluble dye, and in the case of radiation of higher frequency, a phototropic material such as beta-carotene or cholesteryl p-phenylazophenyl carbonate, a novel compound.
Abstract:
BY USING CERTAIN COMPOSITIONS OF MATTER COMPRISING LIQUID CRYSTAL MATERIAL OF THE CHOLESTERIC PHASE HAVING A VISCOSISTY CONTROLLED IN ACCORDANCE WITH A DESIRED LIMIT TEMPERATURE, ONE CAN OBTAIN AN IRREVERSIBLE COLOR CHANGE THAT SERVES AS AN INDICATION THAT SUCH LIMIT TEMPERATURE HAS BEEN EXCEEDED. POSSIBLE USES INCLUDE PACKAGING OF FROZEN FOODS AND DETERMINATION OF BODY TEMPERATURES. CHOLESTERIC LIQUID-CRYSTAL MATERIAL, MICROENCAPSULATED AND/OR IN THIN-FILM FORM, IS FAST-COOLED FROM AN ABOVELIMIT TEMPERATURE AT WHICH IT EXHIBITS A CHARACTERISTIC COLOR OTHER THAN THAT WHICH IT HAS IN THE VICINITY OF THE LIMIT TEMPERATURE, RETAINING ITS HIGH-TEMPERATURE COLOR UNTIL THE LIMIT TEMPERATURE IS EXCEEDED. PARTICULAR CHOLESTERIC-PHASE LIQUID-CRYSTAL MATERIALS AMENABLE TO ACCORDANCE WITH DESIRED LIMIT TEMPERATURES, ARE ALSO TAUGHT. ARTICLES OF MANUFACTURE EMBODYING SUCH COMPOSITIONS ARE DISCLOSED.
Abstract:
STABILITY OF CHOLESTERIC-PHASE LIQUID-CRYSTAL COMPOSITIONS IS IMPROVED BY INCORPORATING THEREIN CHOLESTERYL PNONYLPHENYL CARBONATE, A NEW COMPOUND, MADE BY REACTION OF CHOLESTERYL CHLOROFORMATE WITH P-NONYLPHENOL AND PYRIDINE. THE P-NONYLPHENYL CARBONATE DOES NOT CRYSTALLIZE TO TRUE SOLID IN THREE YEARS, BUT THE CORRESPONDING P-OCTYLPHENYL CARBONATE STARTS CRYSTALLIZING TO TRUE SOLID IN THREE WEEKS.
Abstract:
Increasing dosages of X-ray radiation progressively lower the color-play range of cholesteric-phase liquid-crystal materials. The effect is enhanced when an effective amount of an iodinecontaining compound is used in the liquid-crystal material. Novel iodine-containing compounds are described, and articles are disclosed that give direct-reading indication of the dosages of X-ray radiation that they have received, without need for a separate development operation.
Abstract:
STABILITY OF CHOLESTERIC-PHASE LIQUID-CRYSTAL COMPOSITIONS IS IMPROVED BY INOCORPORATING THEREIN AN AMOUNT, UP TO 100%, OF CHOLESTERYL ERUCYL CARBONATE, A NOVEL COMPOUND, MADE BY REACTION OF CHOLESTERYL CHLOROFORMATE WITH ERUCYL ALCOHOL AND PYRIDINE. THE NOVEL CARBONATE DOES NOT CRYTALLIZE TO TRUE SOLID IN SEVERAL MONTHS, WHEREAS MOST OTHER LIQUID-CRYSTAL COMPOSITIONS TRANSFORM TO TRUE SOLID WITHIN SEVERAL HOURS TO SEVERAL DAYS. MOREOVER, THE NOVEL CARBONATE DOES ITELF EXIBIT A COLOR PLAY, SO THAT IT MAY BE USED IN VERY LARGE AMOUNTS IN CHOLESTERIC-PHASE LIQUIDCRYSTAL COMPOSITIONS, WITHOUT DECREASING THE VIVIDNESS OF THE COLOR CHANGES EXHIBITED THEREBY.