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.

Les vertus des défauts: The scientific works of the late Mr Maurice Kleman analysed, discussed and placed in historical context, with particular stress on dislocation, disclination and other manner of local material disbehaviour

“…I repeat here (see also [88,89]) the curious and amusing tale whereby Frank's "disinclinations" became merely "disclinations". I do so because the story actively involves Maurice, and also because in a relaxed moment, he and I discussed it at some length.…”

“…Parts of this article have been extracted (and much edited) from a longer (eventually unpublished) article on Volterra's scientific work originally intended to accompany her magnificent biography of Volterra [24]. The present article contains reworked versions of parts of: (a) a semi-popular article in Mathematics Today [306], (b) an article celebrating Claudio Zannoni's 70th birthday celebration [89]. I apologise to readers for repetition in the pursuit of a self-contained text.…”

“…For this essay, I have borrowed liberally from a number of previous essays on the history of liquid crystals, both by myself and collaborators, and by others [16,18,88,89,110,306]. I ask that readers forgive me for repeating ideas expressed elsewhere in the interest of producing a self-contained text.…”

Jerry Ericksen: Liquid Crystal Pioneer

“…We give here a brief outline, with a historical focus, enabling " nematically naïve" readers to make sense of what follows. Fuller accounts of different aspects of the early history of liquid crystals can be found elsewhere [7][8][9][10][11][12][13][14][15][16][17][18][19]. The most important key idea is that "liquid crystals" are not crystals at all.…”