Milestone-Proposal:First Exploration and Proof of Liquid Crystals, 1889
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This Proposal has been approved, and is now a Milestone
To the proposer’s knowledge, is this achievement subject to litigation? No
Is the achievement you are proposing more than 25 years old? Yes
Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes
Did the achievement provide a meaningful benefit for humanity? Yes
Was it of at least regional importance? Yes
Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes
Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes
Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes
Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes
Year or range of years in which the achievement occurred:
Title of the proposed milestone:
First Exploration and Proof of Liquid Crystals, 1889
Plaque citation summarizing the achievement and its significance:
The first liquid crystal materials were characterized in 1889 by Otto Lehmann in this building. Lehmann recognized the existence of a new state of matter, “flüssige Kristalle” or liquid crystals, which flows like a liquid but has the optical property of double refraction characteristic of crystals. Lehmann’s work on these compounds opened the door to further liquid crystal research and eventually displays and other applications.
In what IEEE section(s) does it reside?
IEEE German Section
IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:
IEEE Organizational Unit(s) paying for milestone plaque(s):
Unit: IEEE German Section
Senior Officer Name: Jens Haubrock, Chairman
IEEE Organizational Unit(s) arranging the dedication ceremony:
Unit: IEEE German Section
Senior Officer Name: Jens Haubrock, Chairman
IEEE section(s) monitoring the plaque(s):
IEEE Section: IEEE German Section
IEEE Section Chair name: Jens Haubrock, Chairman
Proposer name: Dieter A. Mlynski
Proposer email: Proposer's email masked to public
Proposer name: Peter M. Knoll
Proposer email: Proposer's email masked to public
Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.
Street address(es) and GPS coordinates of the intended milestone plaque site(s):
Kaiserstrasse 12, 76131 Karlsruhe, Germany 49.009515, 8.41233
Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.
Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. The intended site on the campus of Karlsruhe Institute of Technology (KIT) is outside of the old main building of Technische Hochschule Karlsruhe, where Otto Lehmann performed his experiments (see supporting material, Fig.1).
Are the original buildings extant?
Yes (see supporting material, Fig.2).
Details of the plaque mounting:
The plaque shall be mounted on a sand-stone boulder in the court-yard of honour of the old main building of Technische Hochschule Karlsruhe.
How is the site protected/secured, and in what ways is it accessible to the public?
The plaque site is under custody of KIT. It is open to the public without security check.
Who is the present owner of the site(s)?
State of Baden-Württemberg
What is the historical significance of the work (its technological, scientific, or social importance)?
Crystals are well-known since olden times. Since the work of Christiaan Huygens their optical properties, double refraction and polarization especially, have been well-understood in all details. Crystals have been merely known as solids, regardless whether they show the extreme temper of diamond or the plastic modification of iodine silver. In 1889 this utterly changed by the discovery and proof of liquid crystals.
On March 14, 1888 the Austrian botanist Friedrich Reinitzer at German University of Prague passed a letter (see references: 9. Reinitzer’s letter to Lehmann (excerpt), translation from Peter M. Knoll, Hans Kelker, “Otto Lehmann, Researcher of the Liquid Crystals“, Books on Demand, Norderstedt 2010, ISBN 978-3-8391-7439-5) with two samples of cholesterol-acetate and cholesterol-benzoate to Otto Lehmann, at that time Associate Professor at Polytechnic College Aachen. Lehmann was already renowned for his crystallization microscope and for his work on isomorphism and polymorphism of crystals. He had discovered the quintuple polymorphism of ammonium-nitrate and explored the plastic modification of iodine silver.
In his samples Reinitzer had made the observation of groups of crystals floating in a liquid, dramatic colour phenomenon affected by temperature and even more baffling two different melting points. He asked Lehmann for help and explanation (see references: 1. Knoll & Kelker, “Otto Lehmann”, pp. 48-77, excerpt from Peter M. Knoll, Hans Kelker, “Otto Lehmann, Researcher of the Liquid Crystals“, Books on Demand, Norderstedt 2010, ISBN 978-3-8391-7439-5; 2. Dunmur & Sluckin, “Crystals that flow”, pp. 17-39, excerpt from David Dunmur, Tim Sluckin, “Soap, Science, & Flat-Screen TVs, A history of liquid crystals”, Oxford University Press 2011, ISBN 978-0-19-954940-5; 3. Sluckin et al., “Liquid Crystals or Anisotropic Liquids”, pp. 3-24, excerpt from Timothy J. Sluckin, David A. Dunmur, Horst Stegemeyer, “Crystals that flow. Classic papers from the history of liquid crystals”, Taylor & Francis, London/New York 2004, ISBN 0-415-25789-1). Lehmann began to inspect the samples but could not spend much time on it since he just had been appointed as Extraordinary Professor at the Polytechnic College Dresden. Only after he succeeded of Heinrich Hertz as Full Professor at Technische Hochschule Karlsruhe in April 1889 he launched profound research on the cholesterol-benzoate. He reported his first results in a letter of 20 August 1889 to Reinitzer. Instead of crystals floatíng in a liquid he stated a homogeneous mass of plastic crystals, which he described as isomeric modification of the substance with “such a significant plasticity, that one can almost call it liquid”. His paper “Über fließende Krystalle” was published 1889 in Zeitschrift für Physikalische Chemie (see references: 4. Lehmann “On flowing Crystals“, pp.42-53, translation from Timothy J. Sluckin, David A. Dunmur, Horst Stegemeyer, “Crystals that flow. Classic papers from the history of liquid crystals”). It is the very first publication on liquid crystals.
With his proof of the existence of liquid crystals on ammonium-oleate-hydrate and his immense work on more than 100 liquid crystal materials in close cooperation with the still today existing German chemical company E. Merck in Darmstadt, Lehmann founded liquid crystal technology. He opened the door for the work of others and for liquid crystal displays (LCD), finally. Certainly it took almost a century to the discovery of dynamic scattering of liquid crystals in 1968 by George Heilmeier and the invention of the twisted nematic LCD by Martin Schadt and Wolfgang Helfrich in 1970. Today liquid crystals possess a continuously growing field of application and LCDs dominate the huge international market for displays, in particular laptops, tablets and flat-screen TVs.
What obstacles (technical, political, geographic) needed to be overcome?
The tenet of three states of matter, i.e. solid, liquid and gaseous, was commonly considered as indisputable. Therefore Lehmann’s work was confronted with skepticism and even with opponents. His most cutting adversary had been Gustav Tammann from University Göttingen, who insisted that the liquid crystal phase was rather a colloidal emulsion (see references: 1., 2. and 3.). At the annual meeting of German Bunsen Society 1905 in Karlsruhe Lehmann gave a demonstration of liquid crystal phenomena and Rudolf Schenk from University Marburg a short introduction where he explained the falsity of Tammann’s colloidal interpretation (see references: 5. Schenk, “On Crystalline Liquids and Liquid Crystals”, pp. 64-75, translation from Timothy J. Sluckin, David A. Dunmur, Horst Stegemeyer, “Crystals that flow. Classic papers from the history of liquid crystals”). In the discussion Tammann stated: “Soft crystals exist unquestionably, there also should be flowing crystals for all I care, but liquid crystals? Never!” The session chair Jacobus van t’Hoff proposed a commission of German Bunsen Society to clarify the controversy. This assembled in 1906 but no agreement could be obtained.
Liquid crystals became the life-work of Otto Lehmann (see references: 1., 2. and 3.). He solitarily explored them from different aspects such as physics, physical chemistry and electricity. He was nominated for the Nobel price by Carl Benedicks, member of the Nobel committee, first in 1913 and last time in 1922, the year of the sudden death of Lehmann.
What features set this work apart from similar achievements?
Remarkable phenomenon with melting and solidifying of cholesterol-compounds had been observed by M. Berthelot and others already in the 1860th, prior to Reinitzer. But they attributed this to contamination of their preparations. Reinitzer transmitted very pure samples to Otto Lehmann to start his work therewith. In May 1888 Reinitzer published his early observations of liquid crystals with colours and double melting (see references: 10. Reinitzer, “Contribution to the Understanding of Cholesterol”, pp.26-41, translation from Timothy J. Sluckin, David A. Dunmur, Horst Stegemeyer, “Crystals that flow. Classic papers from the history of liquid crystals”), although he did not recognize them as such. This was left to Lehmann.
Lehmann was the prime researcher of liquid crystals and for more than a decade the only one to promote the subject. Only fifteen years after his first publication new names appeared in the field, foremost Daniel Vorländer at University of Halle, Germany, and Georges Friedel at St. Étienne, France. In an article published 1907 Vorländer showed that the real origin of liquid crystallinity is not so much a microscopic shape as noted by Lehmann but rather molecular shape (see references: 6. Vorländer, “Influence of Molecular Configuration on the Crystalline-Liquid State”, pp.84-88, translation from Timothy J. Sluckin, David A. Dunmur, Horst Stegemeyer, “Crystals that flow. Classic papers from the history of liquid crystals”). High influence on the further formation of the subject attained Friedel and his assistant Grandjean (see references: 7. Sluckin et al., “Anisotropic Liquids or Mesomorphic Phasses”, pp. 139-161, excerpt from Timothy J. Sluckin, David A. Dunmur, Horst Stegemeyer, “Crystals that flow. Classic papers from the history of liquid crystals”). In a paper published in 1910 they agreed that Lehmann’s liquids are representatives of a new state of matter. But different from Lehmann Friedel called them anisotropic liquids instead of liquid crystals. In 1922, the year of the sudden death of Lehmann, Friedel summarized the knowledge on the subject and introduced modern liquid crystal terminology (see references: 8. Friedel, “The Mesomorphic States of Matter”, pp. 162-173, translation excerpt from Timothy J. Sluckin, David A. Dunmur, Horst Stegemeyer, “Crystals that flow. Classic papers from the history of liquid crystals”). He affirmed three mesomorphic phases of matter which he called smectic, nematic and cholesteric. But Lehmann’s term “liquid crystal” was already widespread and remained in scientific usage.
Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.
1. Knoll & Kelker, “Otto Lehmann” 2. Dunmur & Sluckin, “Crystals that flow” 3. Sluckin et al., “Liquid Crystals or Anisotropic Crystals” 4. Lehmann, “On flowing Crystals” 5. Schenk, “On Crystalline Liquids and Liquid Crystals” 6. Vorländer, “Influence of Molecular Configuration on the Crystalline-Liquid State” 7. Sluckin et al., “Anisotropic Liquids or Mesomorphic Phases” 8. Friedel, “The Mesomorphic States of Matter” 9. Reinitzer, Letter dated March 14, 1888 to Lehmann 10. Reinitzer, “Contributions to the Understanding of Cholesterol”
Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to email@example.com. Please see the Milestone Program Guidelines for more information.
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