Between 1872 and 1877, Lehmann studied natural sciences at Strasbourg University and obtained the Doctor of Philosophy under crystallographer Paul Groth.
Between 1872 and 1877, Lehmann studied natural sciences at Strasbourg University and obtained the Doctor of Philosophy under crystallographer Paul Groth.
Otto Lehmann was a German physicist. He is considered the "father" of liquid crystal, substances which behave mechanically as liquids but display many of the optical properties of crystalline solids.
Background
Otto was born on June 13, 1855, in Konstanz, Germany, the son of Franz Xavier Lehmann, a professor of science and mathematics at the Gymnasium in Freiburg im Breisgau, who was particularly interested in the mathematical manifestations of organic nature. He sought to develop mathematical formulas for such phenomena as the geometric forms of the leaves of plants, and his interests stimulated the scientific bent of his son.
Education
Between 1872 and 1877, Lehmann studied natural sciences at Strasbourg University and obtained the Doctor of Philosophy under crystallographer Paul Groth.
Lehmann taught in secondary schools at Freiburg im Breisgau and Mulhouse from 1876 to 1883. In the latter year he became Dozent and in 1885 associate professor of physics at the Technische Hochschule at Aachen; in 1888 he was named associate professor at the Technische Hochschule at Dresden; and in 1889 he succeeded Heinrich Hertz as professor of physics at the Technische Hochschule at Karlsruhe. He remained in this post until his death.
Lehmann’s early scientific interest and experimentation were concerned with electric discharges in rarefied gases, but he soon turned his attention to the study of the fine structure of matter as revealed under the microscope. His first major work describing his studies was Molekularphysik, mit besonderer Berüchtsichtigung mikroskopischer Untersuchung und Anleitung zu solchen (1888-1889).
In 1888 the Austrian botanist Friedrich Reinitzer noticed that the solid compound cholesteryl benzoate seemed to have two distinct melting points, becoming a cloudy liquid at 145°C. and turning clear at 179°C. Reinitzer’s observation came to Lehmann’s attention, and he immediately began research on this and other organic substances displaying the same property. He determined in 1889 that the cloudy intermediate phase contained areas that possessed a molecular structure similar to that of solid crystals, and he called this phase “liquid crystal.” In 1922 G. Friedel suggested the term “mesomorphic” to include Lehmann’s liquid crystals as well as any state of matter intermediate between the amorphous and crystalline states; however, the term “liquid crystal” is still employed.
Lehmann published his results in two major works: Flüssige Krystalle (1904) and Die neue Welt der flüssigen Krystalle und deren Bedeutung für Physik, Chemie, Technik und Biologie (1911). His results astonished and perplexed the scientific world, since he demonstrated that the fluidity of many organic substances is not only equal to or greater than water but that they also display the double refracting properties of crystals, some being twice as birefringent as calcite.
Soap, Science, and Flat-Screen TVs: A History of Liquid Crystals
The terms 'liquid crystal' or 'liquid crystal display, LCD, are recognized in the context of flat-screen televisions, but the properties and history of liquid crystals are little known. This book tells the story of liquid crystals, from their controversial discovery at the end of the nineteenth century, to their eventual acceptance as another state of matter to rank alongside gases, liquids, and solids.