Stable colloidal suspension for light valves - contg. ester of aromatic alcohol and polymer e.g. nitrocellulose as suspension medium

摘要

A liquid suspension comprises particles which can react in an electrical field to modify the transmission of radiation through the suspension and, as dispersion medium, an ester derived from an aromatic alcohol and a polymer contg. functional gps. (pref. COOH) or its chain. The suspension is stable when an electrical field is applied to it. It can transmit at least twice the amt. of light than in the absence of an electrical field. Used in light valves. The aromatic ester is pref. an alkyl-aryl ester, esp. an aromatic acetate, e.g. (m)ethyl-phenyl-, propyl-phenyl acetate etc. The polymer is either nitrocellulose or a copolymer, e.g. 3,5,5-trimethylhexylacrylate/bis-2-ethylhexylfumarate/2-hydroxypr- opylacrylate/fumaric acid copolymer and bis-2-ethylhexyl fumarate/3,5,5-trimethylhexylactate/vinylidene chloride/mesaconic acid copolymer.