Characterisation and calibration of three physical forms of thermochromic liquid crystals

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Authors: Bharara, M., Cobb, J.E., Anderson, A.M. and Claremont, D.J.

http://web.ebscohost.com/ehost/detail?vid=3&hid=116&sid=5d88a279-5e87-410e-ae23-8429bdc8fe96%40sessionmgr109&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=aph&AN=27611730

Journal: Imaging Science Journal

Volume: 55

Pages: 232-241

ISSN: 1368-2199

DOI: 10.1179/174313107X189230

Liquid crystal thermography (LCT) provides a colour response proportional to the temperature of a heated surface in contact with the crystals. Thermochromic liquid crystals (TLC) are offered in the form of an emulsion, polymer sheet or latex support. Wider adoption of this technology has been limited due to response time, pressure sensitivity and imaging equipment. It is important to characterise TLC based on their chemical composition, colour play interval, spatial density and repeatability. This paper presents results for three forms of TLC material in terms of the effects of incident lighting, pressure sensitivity and hysteresis. Data are presented in the form of hue versus temperature calibration curves. Hue versus temperature curve shifts towards higher hue values for the identical temperature producing a maximum change of 15–20% in hue when the lighting intensity is changed from minimum to maximum. Hysteresis in the calibration curve occurred when the liquid crystals were heated above the colour play range producing a maximum temperature change of 1°C for R25C5W TLC sheet. This hysteresis was not permanent. The authors recommend using liquid crystals within their colour bandwidth to overcome hysteresis effects. The results may be helpful in developing LCT for various biomedical applications.

This data was imported from Scopus:

Authors: Bharara, M., Cobb, J.E., Anderson, A.M. and Claremont, D.J.

Journal: Imaging Science Journal

Volume: 55

Issue: 4

Pages: 232-241

ISSN: 1368-2199

DOI: 10.1179/174313107X189230

Liquid crystal thermography (LCT) provides a colour response proportional to the temperature of a heated surface in contact with the crystals. Thermochromic liquid crystals (TLC) are offered in the form of an emulsion, polymer sheet or latex support. Wider adoption of this technology has been limited due to response time, pressure sensitivity and imaging equipment. It is important to characterise TLC based on their chemical composition, colour play interval, spatial density and repeatability. This paper presents results for three forms of TLC material in terms of the effects of incident lighting, pressure sensitivity and hysteresis. Data are presented in the form of hue versus temperature calibration curves. Hue versus temperature curve shifts towards higher hue values for the identical temperature producing a maximum change of 15-20% in hue when the lighting intensity is changed from minimum to maximum. Hysteresis in the calibration curve occurred when the liquid crystals were heated above the colour play range producing a maximum temperature change of 1°C for R25C5W TLC sheet. This hysteresis was not permanent. The authors recommend using liquid crystals within their colour bandwidth to overcome hysteresis effects. The results may be helpful in developing LCT for various biomedical applications. © RPS 2007.

This data was imported from Web of Science (Lite):

Authors: Bharara, M., Cobb, J.E., Anderson, A.M. and Claremont, D.J.

Journal: IMAGING SCIENCE JOURNAL

Volume: 55

Issue: 4

Pages: 232-241

ISSN: 1368-2199

DOI: 10.1179/174313107X189230

The data on this page was last updated at 04:46 on November 24, 2017.