We are surrounded by digital displays on our watches, clocks, calculators, televisions, CD and DVD players. The list goes on and on. But last time you glanced at one of those displays, did you take the time to thank Hull and Professor George Gray?
In a solid, molecules always maintain their orientation and stay in the same position with respect to one another. The molecules in liquids are just the opposite: they can change their orientation and move anywhere in the liquid. But there are some substances that can exist in an odd state, not quite solid, not quite liquid. When they are in this state their molecules tend to maintain their orientation like the molecules in a solid, but also move around to different positions like the molecules in a liquid. This means that liquid crystals are neither a solid nor a liquid, hence their seemingly contradictory name.
Liquid crystals were discovered as early as 1888 but their structure and properties were first described by Charles Mauguin in 1911. Over in Hull, Sir Brynmor Jones initiated research in the field of liquid crystals in the 1930s. It was only when he became head of the Department of Chemistry that responsibility for this research passed to George Gray, which was to be a pivotal decision.After the invention of the twisted nematic liquid crystal display in 1972, liquid crystal research suddenly became fashionable. Twisted nematic liquid crystals are naturally twisted. Applying an electric current to these liquid crystals will untwist them to varying degrees, depending on the current’s voltage. Their application however, proved impractical because of a lack of photo-chemically and chemically stable nematic materials that existed in the liquid-crystalline state at room temperature.
In 1973, George Gray changed all that. Alongside Ken Harrison and the Ministry of Defence, he developed cyano-biphenyl liquid crystals, which were found to possess stable nematic phases (meaning they have no spacial ordering of the molecules) at, or close to, room temperature. His invention became an overnight success and the marketplace was suddenly flooded with electronic devices containing small area liquid crystal displays (LCD’s), that for the most part contained Hull materials. LCD’s use these liquid crystals because they react predictably to electric current in such a way that controls the passage of light. The research group was awarded The Queen’s Award for Technological Achievement in 1979.
George Gray went on to be awarded the Fellowship of The Royal Society of Chemistry (FRS), the Fellowship of The Royal Society of Edinburgh (FRSE), honoured with a CBE and receive the Kyoto Laureate of 1995. He also remains an Emeritus Professor at the University of Hull.
LED’s vs. LCD’s
LCD - Liquid Crystal Display - favoured display systems because they are thin, light and require very little power.
LED - Light Emitting Diode - an electronic device that lights up when electricity is passed through it. They are good for displaying images because they can be relatively small and they do not burn out. However, they require more power than LCD’s.
