Thermochromic Liquid Crystals

Reliable micro-scale measurement and control of the temperature are required in developing thermal micro-devices. Available measurement techniques can be largely classified into contact and non-contact groups. While the resistance thermometer, thermocouples, thermodiodes, and thermotransistors measure temperature at specific points in contact with them, infrared thermography, thermochromic liquid crystals (TLC), and temperature-sensitive fluorescent dyes cover the whole temperature field (Yoo 2006). [Pg.27]

In the thermochromic liquid crystal (TLC) the dominant reflected wavelength is temperature-dependent and it has been employed for full-field mapping of temperature fields for over three decades. Although it is non-intrusive and cost effective, there are some problems in applying it to micro-scale measurements, because of size (typically tens of micrometers) and time response (from a few milliseconds to several hundred milliseconds depending on the material and the form). Examples of application are micro-fabricated systems (Chaudhari et al. 1998 Liu et al. 2002) and electronic components (Azar et al. 1991). [Pg.28]

The liquid crystal thermographs method has been used for measuring microtube surface temperature with uncertainties of lower than 0.4 K by Lin and Yang (2007). The average outside diameter micro-tubes was 250 pm and 1,260 pm, respectively. The surface was coated with thermochromic liquid crystal (TLC). The diameters of encapsulated TLC were ranging from 5 to 15 pm. The TLC was painted on the tested tubes surface with thickness of approximately 30 pm. [Pg.28]

I. Cabrera, V. Krongauz, and H. Ringsdorf, Photo- and thermochromic liquid crystal polysilox-anes, Angew, Chem. Int. Ed. Engl. 26, 1178-1180 (1987). [Pg.59]

K.-H. Platzer, C. Hirsch, D. E. Metzger, and S. Wittig, Computer-Based Areal Surface Temperature and Local Heat Transfer Measurements with Thermochromic Liquid Crystals (TLC), Experiments in Fluids, 13, pp. 26-32,1992. [Pg.1231]

Sage I (1991) Thermochromic liquid crystals in devices. In Bahadur B (ed) Liquid crystals applications and uses. World Scientific, Singapore... [Pg.891]

Thermochromic Liquid Crystal Thermochromic fiquid crystals have the property that their dominant reflected wavelength is dependent on the temperature, and they have been employed for full-field mapping of... [Pg.1483]

Parsley M (1991) Hallcrest handbook of thermochromic liquid crystal technology. Hallcrest, Glenview... [Pg.1653]

Hay JL, Hollingsworth DK (1996) A comparison of trichromic systems for use in the calibration of polymer-dispersed thermochromic liquid crystals. Exp Therm Fluid Sci 12 1-12... [Pg.1653]

Ireland PT, Jones TV (1987) The time response of a surface thermometer employing encapsulated thermochromic liquid crystal. J Phys E Sci Instrum 20 1195-1199... [Pg.1653]

Baughn JW, Anderson MR, Mayhew JE, Wolf JD (1999) Hysteresis of thermochromic liquid crystal temperature measurement based on hue. J Heat Trans 121 1067-1072... [Pg.1654]

Wiberg R, Lior N (2004) Errors in thermochromic liquid crystal thermometry. Rev Sci Inst 75 2985-2994... [Pg.1654]

Thermochromic liquid crystals in their raw form can provide a nearly continuous coating on a surface or a nearly continuous distribution in a solvent, meaning that the spatial resolution of the measurement is likely governed by the imaging system. Unfortunately, TLCs in this form are prone to degradation due to chemical... [Pg.3230]

Thermochromic Liquid Crystals for Particle Image Thermometry... [Pg.3272]

Thermochromic Liquid Crystals for Particle Image Thermometry, Fig. 1 Top Color appearance of encapsulated TLC particles from Hallcrest Inc. Bottom Color appearance of custom-made non-encapsulated TLC particles... [Pg.3274]

Thermochromic Liquid Crystals for Particle Image Thermometry, Fig. 2 Schematic of experimental setup... [Pg.3274]

Abdullah N, Abu Talib AR, Jaafar AA, Mohd Salleh MA, Chong WT (2010) The basics and issues of thermochromic liquid crystal calibrations. Exp Therm Fluid Sci 34 1089-1121. doi 10.1016/j. expthermflusci.2010.03.011... [Pg.3279]

Basson M, Pottebaum TS (2012) Measuring the temperature of fluid in a micro-channel using thermochromic liquid crystals. Exp Fluid 53 803-814. doi 10.1007/s00348-012-1326-0... [Pg.3279]

Roesgen T, Totaro R (2002) A statistical calibration technique for thermochromic liquid crystals. Exp Fluid 33 732-734. doi 10.1007/s00348-002-0525-5... [Pg.3279]

I. Sage, Thermochromic liquid crystal devices in liquid crystals-applications and uses, Vol. 3, ed. B. Bahadur (World Scientific, New Jersey, 1990). [Pg.50]

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