The Use of Liquid Crystal Thermography in Selected Technical and Medical Applications—Recent Development

Abstract

Thermochromic liquid crystals (TLC) and true-colour digital image processing have been successfully used in non-intrusive technical, industrial and biomedical studies and applications. Thin coatings of TLC at surfaces are utilized to obtain detailed temperature distributions and heat transfer rates for steady or transient processes. Liquid crystals also can be used to make the temperature and velocity fields in liquids visible by the simple expedient of directly mixing the liquid crystal material into the liquid (water, glycerol, glycol, and silicone oils) in very small quantities to use as thermal and hydrodynamic tracers. In biomedical situations, e.g., skin diseases, breast cancer, blood circulation and other medical application, TLC and image processing are successfully used as an additional non-invasive diagnostic method especially useful for screening large groups of potential patients. The history of this technique is reviewed, principal methods and tools are described and some examples are presented. Also steady-state and transient liquid crystal thermography (LCT) is used to measure local heat transfer on a plate equipped with transverse vortex generators. Automated evaluation allows determining the heat transfer coefficient without arbitrary influence of human interpretation.

Thermochromic Fibers via Electrospinning

“…Eventually the liquid crystal phase appears opaque as the resulting increase in pitch reflects light outside the visible wavelength range. Such materials have been used in thermal mapping and analysis in medical, industrial, and engineering applications such as dynamic heat transfer measurements [11][12][13][14][15][16][17].…”

On a static and dynamic calibration of thermochromic liquid crystals

“…In addition, Stasiek et al [6] have shown the use of TLCs in biomedicine, where we can meet with measurements that can non-invasively detect cancer. The TLC layer is applied to the skin surface and the temperature field in this area is monitored.…”

Influence of photoinduced isomerization on the chiral separation of novel liquid crystalline materials with a diazene moiety

“…The macroscopic chirality of liquid crystalline phase results in special properties such as selective reflection of light and/or (anti)ferroelectricity , which are extremely useful in many applications, e.g. thermographic devices for diagnostics , ultrafast and energy‐saving displays, and sensors . Newly, the effect of chiral ionic liquids as mobile phase (MP) additives on the chiral recognition of acidic enantiomers on a teicoplanin‐based chiral stationary phase has been demonstrated .…”