Two perspectives on the application of liquid crystalline polymers: an introduction to Chapters 9 and 10

During the latter decades of the twentieth century, research and development of liquid crystalline polymers (LCPs) was one of the most rapidly growing areas of materials science. It represented an encounter between two fields: one being liquid crystal science which can be traced back to the work of Reinitzer in 1888, and the other polymer science which was probably not recognisable as such until the 1930s. However, the perception of what an LCP is today, still depends to some extent on one's own background.

Where experience stems from small molecule device materials, LCPs are most readily appreciated as conventional polymer backbones, siloxanes, methacrylates etc., onto which mesogenic groups have been grafted as side-chains, or into which they have been incorporated as rigid sections within the otherwise flexible backbone. The polymeric character is seen as a means of achieving mobile and thus field-active mesogenic groups in the solid state. Furthermore, polymerisation enables suppression of crystallinity, which means that the liquid crystal orientation can be frozen-in on cooling while preserving the optical texture as written.

On the other hand, from the traditional polymeric perspective, LCPs represent a new dimension of processibility whereby comparatively standard fabrication methods can lead to materials with a unique range of properties for general structural applications. The liquid crystallinity is associated with molecular chains which are uniformly stiffer than in conventional polymers.