Some reflections on defects in liquid crystals: from Amerio to Zannoni and beyond

ABSTRACT

Dedicated to Claudio Zannoni on the occasion of his 70th birthday. I discuss some aspects of the history of dislocations, disclinations and defects in liquid crystals, virtual and otherwise, placing Claudio Zannoni in the grand tradition of Italian science.

Graphical Abstract

KEYWORDS:

• Liquid crystals
• Zannoni
• defects

Acknowledgments

This article has largely been written within the hallowed historical portals of the Politecnico di Milano. I am grateful to the physicist Paolo Biscari who invited me here, and to the mathematician Stefano Turzi and the chemist Guido Raos with whom I have collaborated in the past and still continue to enjoy fruitful scientific interaction. Many colleagues across Europe, too many to name personally, have first borrowed texts in several different languages from libraries accessible to them and not to me, and then photocopied or scanned them so I would have continuing access. The personal recollections of several colleagues no longer with us, specifically Charles Frank, Jacques Friedel, George Gray and Frank Leslie, have been invaluable in building up a picture of the ongoing field in which we have the privilege to work. Maurice Kléman’s 1977 text on Points, Lines and Walls [84] (much fingered, in the original French) has accompanied me across Europe and back, and continues to be an inspiration. Long ago, it was Nils Schopohl who persuaded me that he could transfer experience in superconductivity to enable me to think more fruitfully about defects in liquid crystals.

I owe my interest in Vito Volterra to the historian of science Judith Goodstein. Parts of this article have been extracted (and much edited) from a longer (eventually unpublished) article on Volterra’s scientific work originally intended to accompany her magnificent biography of Volterra [24].

Finally, my career in liquid crystals was not originally inspired by Geoffrey Luckhurst, but for almost 40 years he has been my closest professional local colleague and my admiration for his continuing skills knows few bounds. It was Geoffrey who brought Claudio Zannoni to Southampton, and through whom I have met an incomparable colleague with innumerable strings to his bow. Finally, I thank Claudio himself and the editorial board of ‘Liquid Crystals’ for doing me the honour of asking me to contribute to this volume.

Disclosure statement

I declare no conflicts of interest, other than those implicit in the paragraphs above.

Notes

1. Folk-history tends to report this work as 1905, but Volterra’s work as occurring only later in 1907, but Folk-historians tend not to read either Italian or German, and so Timpe’s work tends to remain unread.