Quick measurement of electrorheological effect for small amounts of nematic liquid crystal. (10th July 2015)

• Record Type: Journal Article
• Authors: Tadokoro, Chiharu; Hosomi, Yuki; Nakano, Ken
• Is Part Of: Measurement science & technology. Volume 26:Number 8(2015:Aug.)
• Publication Date: 2015-07-10
• Subjects: viscosity -- liquid crystal -- electrorheological fluid -- non-Newtonian fluid; Physical measurements -- Periodicals; Scientific apparatus and instruments -- Periodicals; Equipment and Supplies -- Periodicals; Science -- instrumentation -- Periodicals; Technology -- instrumentation -- Periodicals; Mesures physiques -- Périodiques; Physical measurements; Scientific apparatus and instruments; Periodicals; 502.87
• DOI: 10.1088/0957-0233/26/8/085303
• Languages: English
• ISSNs: 0957-0233

Abstract

Abstract: A quick measurement method of effective viscosity, employing damped oscillation between two parallel plates, was proposed to examine the electrorheological (ER) effect for small amounts of nematic liquid crystal (LC). To demonstrate the validity of the method, the viscosity measurements were conducted for ordinary liquids [polyalphaolefins (PAOs)] and a nematic LC [4-pentyl-4′-cyanobiphenyl (5CB)] by using a newly developed apparatus that embodied the measurement principle. The viscosity measurements for PAOs showed that when the film thickness is in the submillimeter range (e.g. 0.2 mm), this method provides reliable values of the effective viscosity. The viscosity measurement for 5CB showed that this method evaluates the ER effect with a few dozen cubic millimeters of the sample (e.g. 16 mm 3 ) under the application of a voltage (e.g. 0 to 300 V). It was confirmed that the effective viscosities of 5CB measured at various conditions were scaled to a single master curve as a function of the applied voltage, effective velocity and film thickness.