Journal ArticleDOI
Effects of Monomer Structure on Their Organization and Polymerization in a Smectic Liquid Crystal
C. Allan Guymon,Erik N. Hoggan,Noel A. Clark,T. P. Rieker,David M. Walba,Christopher N. Bowman +5 more
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TLDR
These polymerization precursor structures suggest novel materials-design paradigms for gel LCs and nanophase-separated polymer systems.Abstract:
Photopolymerizable diacrylate monomers dissolved in fluid-layer smectic A and smectic C liquid crystal (LC) hosts exhibited significant spatial segregation and orientation that depend strongly on monomer structure. Small, flexible monomers such as 1,6-hexanediol diacrylate (HDDA) oriented parallel to the smectic layers and intercalated, whereas rod-shaped mesogen-like monomers such as 1,4-di-(4-(6-acryloyloxyhexyloxy)benzoyloxy)-2-methylbenzene (C6M) oriented normal to the smectic layers and collected within them. Such spatial segregation caused by the smectic layering dramatically enhanced photopolymerization rates; for HDDA, termination rates were reduced, whereas for C6M, both the termination and propagation rates were increased. These polymerization precursor structures suggest novel materials-design paradigms for gel LCs and nanophase-separated polymer systems.read more
Citations
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Journal ArticleDOI
Self-Assembly of Phase-Segregated Liquid Crystal Structures
TL;DR: In this paper, phase segregation and self-assembly are used to enhance anisotropic properties such as ionic conductivity in liquid crystalline materials, such as hydrogen bonding and ionic interactions.
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Photoinduced Ultrafast Dye-to-Semiconductor Electron Injection from Nonthermalized and Thermalized Donor States.
TL;DR: It is shown that the dominating part of the electron transfer proceeds extremely rapidly from the initially populated, vibronically nonthermalized, singlet excited state, prior to electronic and nuclear relaxation of the molecule.
Journal ArticleDOI
Electron injection and recombination in dye sensitized nanocrystalline titanium dioxide films: A comparison of ruthenium bipyridyl and porphyrin sensitizer dyes
TL;DR: In this article, the sensitizing efficiency of different sensitizer dyes adsorbed to nanocrystalline titanium dioxide films has been investigated, and the photophysics of Ru(dcbpy)2(NCS)2 in solution is dominated by ultrafast (1 ns) π* singlet excited states and only weak singlet/triplet mixing.
Journal ArticleDOI
Femtosecond absorption spectroscopy of transition metal charge-transfer complexes.
TL;DR: Initial observations in the application of femtosecond time-resolved absorption techniques to the study of the photophysics of transition metal complexes are described and examples detailing these dynamics as they occur in the charge-transfer excited states of transition-metal polypyridyl chromophores are included.
Journal ArticleDOI
First Observation of the Key Intermediate in the “Light-Switch” Mechanism of [Ru(phen)2dppz]2+
E. J. C. Olson,Dehong Hu,A. Hormann,A. M. Jonkman,Michelle R. Arkin,Eric D. A. Stemp,Jacqueline K. Barton,P. F. Barbara +7 more
TL;DR: In this article, the photophysics of [Ru(phen)2dppz]2+ in aqueous solution, and in mixtures of acetonitrile and water, by time-resolved absorption and emission spectroscopies were described.
References
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MonographDOI
Liquid crystal dispersions
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Journal ArticleDOI
Cholesteric liquid crystal/polymer dispersion for haze‐free light shutters
TL;DR: In this paper, a new dispersion involving a polymer in low concentration with a cholesteric liquid crystal is reported, and two types of light modulators from these materials are described as a normal mode shutter which is opaque (light scattering) in the field-off state and transparent in field-on state and a reverse-mode shutter with the opposite field conditions.
Journal ArticleDOI
Reaction behaviour and kinetic constants for photopolymerizations of multi(meth)acrylate monomers
TL;DR: In this article, the polymerization behavior of a series of multifunctional methacrylate and acrylate monomers was studied using differential scanning calorimetry to characterize the reaction rate profiles.
Journal ArticleDOI
Polymer-dispersed liquid crystals From the nematic curvilinear aligned phase to ferroelectric films
TL;DR: A review of the work on nematic and cholesteric PDLCs can be found in this article, where the use of ferroelectric liquid crystals for PDLC applications is also discussed.
Journal ArticleDOI
Insitu photopolymerization of an oriented liquid-crystalline acrylate .2.
TL;DR: The photo-initiated polymerization of 4-biphenylyl 4-(6-acryloyloxyhexyloxy)benzoate (1) in its oriented liquid-crystalline state was studied in this paper.