Monday 24 February 2014

Liquid crystals: revolutionary science

by Toby Benham

Once a scientific curiosity on the fringes of scientific research, the liquid crystal industry is now estimated to be worth around £56 billion. They are essential to everyday items such as mobile phones, laptops and televisions in creating liquid crystal displays (LCD). Although the UK doesn't profit largely from the industry, all these technologies can be accredited to the breakthrough made by the late British Professor George Gray of Hull University and the research his team conducted in the 1970s.

Originally shunned financial support for his research, it was the minister for technology, John Stonehouse, who initiated the advance in the field. He wanted a technology to replace the expensive cathode ray tubes causing a hole in the Ministry of Defence's budget in producing flat screen colour displays. Liquid crystals were known but little appreciated. They can be described as anisotropic molecules with long range orientational order and some degree of liquid like order. In other words they possess crystalline structure while still maintaining the ability to flow like a fluid in certain directions. This means that they interact with light differently in different directions due to differences in polarisability. The main reason that they are so useful is because applying an electric field can lead to a switch in alignment of the crystal. This feature can be exploited to display different colours when different voltages are applied.

By 1973, Gray and his team had been  able to exploit this, having synthesised a new class of liquid crystals called cyanobiphenyls which were stable, yet still “flippable”. The first liquid crystal devices appeared the following year and Gray became a Professor of Organic Chemistry. Described as a brilliant teacher, most of his students went on to leading positions in industry and academe.

He was appointed CBE in 1991, but his favourite prize was reportedly having a train named in his honour. Gray never won the Nobel Prize and is little known but should be remembered as a British great who contributed much not only to his field of science but to modern day life. Liquid crystals are of great use with so many applications and the field is in constant development of what Gray started.