The 2016 Luckhurst-Samulski Prize

Since the Luckhurst-Samulski Prize was first announced in Liquid Crystals eight years ago [1] it has quickly become established as a major prize in the field. On launching this annual prize, the terms were kept simple: it will be awarded annually for the best paper published in Liquid Crystals from the preceding year. The first seven prizewinning papers are listed in Table 1. This outstanding collection of papers spans a wide range of subject areas truly befitting the breadth of liquid crystal science and technology.

Table 1. Previous winners of the Luckhurst-Samulski Prize.

Year	Authors	Title	Reference
2009	Goodby JW, Saez IM, Cowling SJ, Gasowska JS, MacDonald RA, Sia S, Watson P, Toyne KJ, Hird M, Lewis RA, Lee S-E, Vaschenko V.	Molecular complexity and the control of self-organising processes.	[2]
2010	Jakli A.	Electro-mechanical effects in liquid crystals.	[3]
2011	Skarabot M, Lokar Z, Gabrijelcic K, Wilkes D, Musevic I.	Atomic force microscope based method of measuring short cholesteric pitch in liquid crystals.	[4]
2012	Picken SJ, Dingemans TJ, Madsen LA, Francescangeli O, Samulski ET.	Uniaxial to biaxial nematic phase transition in a bent-core thermotropic liquid crystal by polarising microscopy.	[5]
2013	Pieranski P, Yang B, Burtz LJ, Camu A, Simonetti F.	Generation of umbilics by magnets and flows.	[6]
2014	Takezoe H, Araoka, F.	Polar columnar liquid crystals	[7]
2015	Alshomrany A, Clark NA.	Fisheye lens conoscopy	[8]

In 2016, Liquid Crystals was expanded from 12 to 15 issues and we published almost 230 papers. The daunting task of selecting the very best of these fell to the Prize’s Selection Committee, consisting of the Editorial Board and myself as Editor. The selection process begins with the referees who can flag a paper as being a worthy Prizewinner after peer review. These suggestions are then collated and brought to the attention of the Selection Committee to assist it in drawing up the long list of nominations from which the eventual Prizewinner is chosen. Each Selection Committee member can nominate as many, or as few, papers as they wish. The papers with the most nominations form a shortlist which is voted upon by the Selection Committee, and the paper which receives the most votes is declared the winner. Any member of the Selection Committee who has a paper on the shortlist is exempted from the final stage of the selection process.

The shortlist for the 2016 Luckhurst-Samulski Prize consisted of eight papers, and any one of these would have made an exceptional winner of the Prize. On behalf of the Journal and the Publisher, I am very pleased to announce that the 2016 Luckhurst-Samulski Prize has been awarded to Alya Dawood, Martin Grossel, Geoffrey Luckhurst, Robert Richardson, Bakir Timimi, Neil Wells and Yousif Yousif for their paper entitled On the twist-bend nematic phase formed directly from the isotropic phase [9]. The twist-bend nematic, N_TB, phase has been one of, if not the, hottest topic in liquid crystal science in recent years. This paper describes how the authors designed, synthesized and characterized a mesogen exhibiting the N_TB-I transition, the first pure material to do so. As they note in their paper, their search was guided by “pragmatism and theory”. Drawing upon the analogy between the behaviour of the N_TB-N and SmA-N transitions, the authors argued that that the N_TB phase should form directly from the I phase via a first order transition. Furthermore, theory predicted that such a transition should occur when the angle between the mesogenic arms of a symmetric V-shaped molecule is 130°. For a dimer, this suggested that a short spacer was required. The authors prepared five members of the N,N’-bis[4’-(4”-ethyloxybenzoyloxy)benzylidene]alkane-α,ω-diamines with propyl, pentyl, heptyl, nonyl and undecyl spacers. All these materials exhibit the N_TB phase which was characterised using polarizing optical microscopy, differential scanning calorimetry, X-ray diffraction, and ²H NMR spectroscopy. The dimers having the four longer spacers showed the phase sequence Cr-N_TB-N-I. As predicted, however, for the shortest spacer a direct N_TB-I transition was observed and accompanied by a large transitional entropy. The texture of this N_TB phase, taken from the prizewinning paper, is shown Figure 1. The Selection Committee viewed this paper as being highly significant to our developing understanding of the N_TB phase and which will certainly trigger further experimental and theoretical works.

Figure 1. The rope-like texture of the N_TB phase formed directly from the I phase (reproduced with permission from [9]).

The remaining seven papers on the short-list were each highly commended by the Selection Committee and merit recognition here. In strict chronological order of publication, the first of these seven highly commended papers was by Yuriy Garbovskiy entitled Electrical properties of liquid crystal nano-colloids analysed from perspectives of the ionic purity of nano-dopants [10]. This paper describes an analysis of the concentration of mobile ions in liquid crystals doped with nano-objects within the framework of Langmuir isotherms assuming a partial ionic contamination of the nanodopant. The agreement between the predictions of this approach and a broad range of experimental data is excellent, and will guide the design of new ion capturing materials. The Selection Committee considered this paper to be an important development in our understanding of mobile ions in liquid crystal nano-colloids, and will have applicability in technological applications.

In the second of the shortlisted papers entitled Uniform and fast switching of window-size smectic A liquid crystal panels utilising the field gradient generated at the fringes of patterned electrodes, Daping Chu and co-workers [11] describe a new and practical method to enable smectic A liquid crystal devices to switch uniformly and fast from the clear state to a scattered state. The Selection Committee considered this to be an important advance in the development of the potential device applications of the SmA phase.

The third paper by Noel Clark and co-workers entitled Manipulating the twist sense of helical nanofilaments of bent-core liquid crystals using rod-shaped, chiral mesogenic dopants [12] describes how homochiral helical nanofilaments may be obtained from achiral bent-core liquid crystals by adding chiral, rod-like dopants that are miscible with the bent-core molecules. The chirality of the dopant is transferred to the helical nanofilament superstructure and allows for control of their twist sense throughout the entire sample. The Selection Committee viewed this paper as a key advance in our ability to control the chirality of liquid crystal systems.

The fourth paper by James Addis and colleagues entitled Second-harmonic generation and the influence of flexoelectricity in the nematic phases of bent-core oxadiazoles [13] shows that the second harmonic intensity produced by bent-core nematic liquid crystals is greater that that found for rod-like nematogens. This observation is discussed in terms of the dependence of the second harmonic intensity on temperature, elastic constants and flexoelectric coefficients. The Selection Committee viewed this paper as an important contribution to our fundamental understanding of the behaviour of bent-core liquid crystals.

2016 marked the thirtieth anniversary of Liquid Crystals [14] and we celebrated this event by publishing a special issue containing 30 invited articles, each written by an early career researcher. I am delighted to report that three of these papers feature amongst those highly commended by the Selection Committee. The first of these, and fifth short-listed, by Yoshida and Kobashi entitled Flat optics with cholesteric and blue phase liquid crystals [15] describes how the wavefront of light reflected from cholesteric liquid crystals and blue phases can be designed by controlling their helix phase. The Selection Committee considered this to be an excellent account of the dependence of the reflected light phase on the helix phase, and the effect of chiral handedness.

The sixth paper entitled Non-electronic gas sensors from electrospun mats of liquid crystal core fibres for detecting volatile organic compounds at room temperature by Jan Lagerwall and co-workers [16] describes changes in the optical properties of coaxially spun liquid crystal-polymer fibre mats when subjected to the vapour of volatile organic compounds. This rapid change can be visible to the naked eye, occurs at room temperature and requires no power supply. These materials thus have wide ranging application potential, perhaps most notably as wearable gas sensors. The Selection Committee considered this paper to be not only an excellent account of the fundamental behaviour of these novel materials but also of their considerable application potential, and which will promote further developments in this area.

The final paper of the shortlist entitled Applications of liquid crystals in biosensing and organic light-emitting devices: future aspects by Santanu Kumar Pal and colleagues [17] overviews their recent advances in the development of new technological applications of liquid crystals, specifically, biosensors and organic light emitting diodes. The Selection Committee considered that this excellent review will stimulate much further work, both fundamental and technological, in these non-display areas.

When the 2016 Prizewinning paper by Geoffrey Luckhurst and his colleagues is taken together with the other seven shortlisted papers they constitute an exceptional and highly diverse collection of work. I would strongly recommend everybody to read these articles. Both Geoffrey Luckhurst and Ed Samulski are now winners of the Luckhurst-Samulski Prize, but, in the year that Real Madrid became the first football (soccer to our friends across the Atlantic) team to win the European Champions League in consecutive years since the competition was relaunched in 1992-93, we are still to see an author manage to be awarded the Luckhurst-Samulski Prize for a second time.

I would like to thank everyone who published their work in Liquid Crystals during 2016 and the Selection Committee for all their hard work in selecting the 2016 Luckhurst-Samulski Prize winner. We will soon begin the selection process for the 2017 Prize!