Photopolymerization of self-organizing ionic liquids

Bongartz, Nils; Goodby, John W.

doi:10.1039/c0cc01470b

Cited by 15 publications

(6 citation statements)

References 22 publications

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“…In the SmC phase, the out-of-plane organisation of the molecules is likely to be more well-defined than in the SmA phase. However, it should be noted that when the cross-sectional areas of the central core and the terminal chains do not match then curvature in the packing of the molecules will arise and layer distortion will occur in a similar way to the way in which amphiphiles form curved packing structures [28][29][30] (see Figure 7). Such distortions can be localised into defects, which can affect the organisation of tilted phases in devices in the form of chevrons.…”

Section: Molecular Tilt and Space Fillingmentioning

confidence: 95%

What makes a liquid crystal? The effect of free volume on soft matter

et al. 2015

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In this article, we probe the formation of liquid crystal and soft crystal phases as a consequence of minimising the free volume of the system either through design engineering of molecular shape or through deformation of molecular architecture. Following this concept, a number of realisations were made, for example, smectic A phases with variable layer spacing, smectic C phases without layer shrinkage, lattices of free space and fibres in N TB phases.Prologue: At the start of my thesis research in 1974, the knowledge of the structures of smectic liquid crystals was somewhat limited. Even though his thought predated the discovery of ferreoelectric behaviour in liquid crystals, George Gray had the idea that smectic C (SmC) liquid crystals might underpin potential new display applications. As I launched into synthesising new SmC variants, I started to think about why molecules should tilt over in their layers, and then onwards to question why do certain materials exhibit different forms of smectic B (SmB) phases, which was before their classification as hexatic and crystal B phases, etc. In those days I became very much interested in how the molecules pack together in condensed phases. With protractors, compasses and graph paper, the Cartesian coordinates of the atoms of a variety of molecular structures in their all trans forms were located, and their mass axes were determined for their structures by computer methods using ticker-tape which used to shoot out of the machine in volumes to yield just one result -the minimum moment of inertia. Flipping the structures about their inertia axes by 180°yielded the surface contours and the rotational volumes of the molecules. Packing them together in ways to minimise the free volume gave snapshot pictures of the local structures of various mesophases.[1] Over the passing years, I discarded this methodology for the following reasons: (1) the molecules in liquid crystal phases are rotationally disordered and are in dynamic fluctuation as demonstrated by neutron scattering studies [2,3]; (2) X-ray data showed that the molecules pack close enough together that they interpenetrate each other's independent rotational volumes, meaning they share each other's space [4,5]; (3) there were no ways to simulate the interpenetration of space, and what was free space and what was not; (4) there were only a few families of materials that could provide full data sets on structure versus phase formation; to this day there are still relatively few full homologous series of materials being reported; and lastly (5) there was no discussion of how to determine the energy cost of not fully packing space with molecules in order to minimise the remaining free volume. However, with the advent of research exploring liquid crystal materials of unconventional structure and new modelling methods such as density functional theory (DFT) simulations becoming available, our work again began to explore the steric packing arrangements of the molecules in condensed phases. [6][7][8][9][10] Then recently, one o...

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Section: Molecular Tilt and Space Fillingmentioning

confidence: 95%

What makes a liquid crystal? The effect of free volume on soft matter

et al. 2015

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“…For the homologous series of the 4‐alkoxy‐4′‐cyanobiphenyls, the trends in the nematic to liquid transition temperatures, shown in Figure 4, reflect the “dichotomous” nature of the nanophase segregation between the aromatic and aliphatic parts of the molecules, where the π to σ electron balance is akin to the “hydrophobic effect” found in surfactants 33–37. For short aliphatic chains the crystal state dominates and for long chains waxy, layered smectic phases dominate, but in between the balance is such that nematic phases and low melting temperatures are found…”

Section: Electrostatic Interactionsmentioning

confidence: 98%

Nano‐Segregation and Directed Self‐Assembly in the Formation of Functional Liquid Crystals

Goodby

Davis

Mandle

et al. 2012

Israel Journal of Chemistry

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It is often a question that is asked: "How can you predict from the molecular architecture of a material the structure of the condensed phases it forms, and what properties would you expect the phase to exhibit?" For liquid crystals, knowing how to design materials for particular applications requires precision molecular engineering. In this article we examine how molecular topology and interactions influence phase formation and report on material design.

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“…The polymers could also be prepared in the crosslinked form by copolymerization with a bis‐diallylammonium salt. The crosslinked polymer showed high stability and retained the texture even up to around 150 °C …”

Section: Applicationsmentioning

confidence: 99%

Photoinitiated polymerization in ionic liquids and its application

Andrzejewska

2016

Polymer International

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Ionic liquids (ILs) are low-melting organic salts often liquid at room temperature, whose unique properties are the reason of increasing interest for their applications as solvents, reaction media and functional additives. The exceptional properties of ILs have proved to be particularly useful in polymer science giving the potential to produce polymeric materials with improved properties or to immobilize ILs in polymer matrices while keeping their special characteristics. One of the possibilities is polymerization in ILs which can also affect positively polymerization reactions. An especially attractive technique is photopolymerization due to the ease of process control, short reaction time and ambient working temperature. This review gives a literature survey of developments in photopolymerization processes carried out in ILs as well as applications of these processes. It covers both the photopolymerization in ILs as well as photopolymerization of IL monomers. The first part presents a short overview of physicochemical and photochemical properties of ILs; it includes also photochemical reactions and photoinitiation of polymerization in ILs. The second part covers both the basic research (kinetics of photopolymerization including polymerization rate coefficients and polymerization of IL monomers) as well as applications of UV-induced polymerization in ILs.

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Photopolymerization of self-organizing ionic liquids

Cited by 15 publications

References 22 publications

What makes a liquid crystal? The effect of free volume on soft matter

What makes a liquid crystal? The effect of free volume on soft matter

Nano‐Segregation and Directed Self‐Assembly in the Formation of Functional Liquid Crystals

Photoinitiated polymerization in ionic liquids and its application

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