The 2019 Luckhurst-Samulski Prize

The Luckhurst-Samulski Prize was announced by the present Editor, Corrie Imrie [1], in 2009 when he explained that with the Publishers, Taylor & Francis, it had been decided to inaugurate a new Award named for the Founding Editors of the Journal [2]. Since that time the Prize and its Modus Operandi were rapidly established. It is to be awarded for the best paper published in Liquid Crystals in a given year and the list of such papers is shown in Table 1. Interestingly ‘best’ is to be decided each year by the Prize Selection Committee which is composed of the Editorial Board and the Editor. The referees of the papers appearing in the Journal are also involved in this process; they are invited to indicate if the paper they have reviewed might be considered for the Prize. This list together with that suggested by members of the Editorial Board comprises the long list or pool of potential prize winners which is to be considered by the Selection Committee. They are then asked to nominate those papers which will form the short list and this is then to be considered by a revised Selection Committee; in the sense that Board Members who are authors of the papers on the short list have been removed from it. In addition if the Editor has also authored a paper on this list then he will be replaced by a Founding Editor who then chairs the activities of the Prize Selection Committee; I now have this honour. I should also say that I have been aided in my task by Scott Yearsley representing the Publishers.

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 SE, Vaschenko V.	Molecular complexity and the control of self-organising processes.	[3]
2010	Jakli A.	Electro-mechanical effects in liquid crystals.	[4]
2011	Skarabot M, Lokar Z, Gabrijelcic K, Wilkes D, Musevic I.	Atomic force microscope based method of measuring short cholesteric pitch in liquid crystals.	[5]
2012	Picken SJ, Dingemans TJ, Madsen LA, Frascescangeli O, Samulski ET.	Uniaxial to biaxial nematic phase transition in a bent-core thermotropic liquid crystal by polarising microscopy.	[6]
2013	Pieranski P, Yang B, Burtz LJ, Camu A, Simonetti F.	Generation of umbilics by magnets and flow.	[7]
2014	Takezoe H, Araoka, F.	Polar columnar liquid crystals.	[8]
2015	Alshomrany A, Clark NA.	Fisheye lens conoscopy.	[9]
2016	Dawood AA, Grossel MC, Luckhurst GR, Richardson RM, Timimi BA, Wells NJ, Yousif YZ.	On the twist-bend nematic phase formed directly from the isotropic phase.	[10]
2017	Paterson DA, Abberly JP, Harrison WT, Storey JM, Imrie CT.	Cyanobiphenyl-based liquid crystal dimers and the twist-bend nematic phase.	[11]
2018	Tschierske C.	Mirror symmetry breaking in liquids and liquid crystals.	[12]

It is for this reason that I am especially pleased to announce that from the short list of six quality papers that entitled Sulfur-linked cyanobiphenyl-based liquid crystal dimers and the twist-bend nematic phase. [13] by E. Cruickshank, M. Salamonczyk, D. Pociecha, G.J. Strachan, J.M.D. Storey, C. Wang, J. Feng, C.H. Zhu, E. Gorecka and C.T. Imrie has been awarded the Luckhurst-Samulski Prize for 2019. Their novel paper describes the design and synthesis of a range of liquid crystal dimers with particular attention to their formation of the twist-bend nematic phase. To do this attention is paid to the molecular curvature of the dimers. This is achieved by focusing on the introduction of one or two sulfur atoms into the link between the cyanobiphenyl groups (CB) and the alkane spacer, n, joining them. The dimers so created are CBSnSCB, CBSnOCB and CTnSCB where CT denotes a cyanoterphenyl group. The properties of the new dimers were then compared with those of the methylene-linked CBnCB dimers as well as those having ether links. To understand the transitional properties in molecular terms use is made of space-filling models and density functional theory. One of the other key properties employed is the optical birefringence, related to the orientational order of the phases and its variation with temperature. Another view of this is provided by the X-ray scattering patterns which also gave the heliconical pitch for the N_TB phases of CBS7SCB, CBO5SCB and CT6SCB. These revealed a critical increase in the pitch as the transition to the nematic phase is approached. As will be apparent this is a detailed and ingenious investigation; it certainly merits careful study.

I can also commend the other five papers on the short-list to you and I shall comment briefly on them here in the order that they occur on the list.

The first is Considerations in the determination of orientational order parameters from X-ray scattering experiments.[14] and is by M.T. Sims, L.C. Abbott, R.M. Richardson, J.W. Goodby and J.N. Moore. Here the two order parameters considered are the important second- and fourth-rank Legendre polynomials, <P₂> and <P₄>, and how they can be determined using X-ray scattering. The important experimental factors related to the background of the scattering pattern and then to the baseline are dealt with. As significant as these are the extraction of the two order parameters from the scattering intensity and the optimal approaches that have been employed for this task are also described here.

The second paper is entitled Photocontrol of helix handedness in curled liquid crystal elastomers.[15] by M. Wang, Y. Han, L.-X. Guo, B.-P. Lin and H. Yang. This is an intriguing and wide ranging study concerned as it is with the chirality exhibited by helical curling which surprisingly occurs widely. Here the authors are concerned with the preparation of a liquid crystal system where its chirality might be changed. They achieve this with a composite polymeric ribbon including a dye. This may then be converted from an achiral ribbon into a left-handed helix by IR irradiation a process reversed by removing the IR. In addition a right-handed helix is created by UV irradiation which process may be reversed by heating.

The following paper is by M. Mrukiewicz, O.S. Iadlovska, G. Babakhanova, S. Siemianowski, S.V. Shiyanovskii and O.D. Lavrentovich; the title is Wide temperature range of an electrically tunable selective reflection of light by oblique helicoidal cholesteric. [16] The oblique helicoidal cholesteric phase (Ch_OH) indicated here, has its director tilted with respect to the helix axis, and was composed of three nematogens whose interactions result in the cholesteric phase. Their components are bent liquid crystal dimers together with rod-like monomers added to which is a chiral dopant to give the N_TB* phase responsible for the tuneable Bragg reflection of light. The results obtained are fascinating and certainly of potential importance.

The fourth paper with its truly intriguing title of Cholesteric-type cellulosic structures: from plants to applications. [17] is by A.P.C. Almeida, J.P. Canejo, P.L. Almeida and M.H. Godinho. The range of systems with cellulosic structures is broad and includes those found in the cell wall of plant tissue. As we learn Bouligand had shown that the structure and properties of cholesterics were close to those observed for the cuticles of certain beetles as well as other biological systems. It is also fascinating to learn that helicoidal responsive structures imprinted on some plants remain active in dead tissues after leaving the plant.

The fifth and final paper on the short list is by A. Yoshizawa and entitled Nanostructured assemblies of liquid-crystalline supermolecules: from display to medicine. [18] and like the previous paper is equally intriguing. The sub-title of the final section is Effects of liquid-crystallinity on anticancer activities. It describes the role of the surprisingly simple monomers, 4-cyano-4'-(ω-hydroxyalkyloxy)biphenyl, on the cell growth of human lung cancer A549. The widest nematic range of the monomer with a terminal heptane chain was found to exhibit the strongest inhibition on cell proliferation. Of the other two sections the first is concerned with the stabilisation of blue phases and the second with spontaneous mirror symmetry breaking in achiral flexible trimers rated as one of the most exciting research areas. It seems clear that there should be something here to interest everybody not only in this final paper but also in the others.

It is certainly my pleasure to thank all members of the Prize Selection Committee for their invaluable efforts in constructing the short list and then selecting the Luckhurst-Samulski Prize for 2019. As you will be well aware it is really late in this year of the COVID-19 Pandemic. Indeed it seems that even with the arrival of the vaccines there may still be some way to go. However, the hunt for the Luckhurst-Samulski Prize for 2020 and the creation of the best papers for 2021 might well help put us in a good state in the coming year. We trust you and your family will enjoy good health in the New Year.