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In this work, we report a first detailed study of the mesophasic behaviour of the calamitic liquid crystal, a (4,4′-bis(4″-carboxybelzyloxy)biphenyl derivate, labelled 9/2 RS/RS, showing an isotropic-isotropic-(columnar)-cubic phase behaviour on cooling.1H NMR diffusometry allowed to distinguish between the two isotropic phases in terms of diffusion characterized by different Arrhenius activation energy, while13C NMR static measurements and2H NMR investigations were of help in understanding the orientational ordering properties of the metastable columnar phase and confirmed the isotropic state of the sample in the cubic phase. [ABSTRACT FROM AUTHOR]

We present the characterization of new binary mixtures made of two rod-like molecules: a photosensitive azobenzene derivative (calledJ7) and a smectogen (calledM11). The interest in these two specific compounds is related to their use as basic constituents of photo-active liquid crystalline elastomers and their opto-mechanic applications. Differential scanning calorimetry and polarized optical microscopy were used to characterize the phase diagram of the binary systemJ7-M11.2H NMR spectroscopy of the2H-selectively labelledM11, either alone or as a probe in binary mixtures containing different ratiosJ7/M11, was applied to study the orientational ordering properties. [ABSTRACT FROM PUBLISHER]

New bilayered composite systems with tunable and temperature-dependent formation of periodical wrinkles on the surface are the object of this report. The samples were prepared by spin-coating deposition of a thin film of the conducting polymer poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on the surface of standard monodomain liquid crystal elastomer (LCE) films. Several bilayered materials were prepared by changing the thickness of PEDOT:PSS nanofilms. Basic characterization showed very good stability and adhesion between the two components also after performing multiple heat cycles around nematic-to-isotropic transition temperature of the LCE. Interestingly, formation of uniaxially aligned microwrinkles was observed, with most of the wrinkles aligned along perpendicular direction with respect to the nematic director, due to reversible elongation/compression of the LCE during thermal cycles. [ABSTRACT FROM PUBLISHER]

In this paper, some of the most relevant 2H NMR experiments with the aim of determining the biaxial nature of the nematic phase in several thermotropic liquid crystals are overviewed. Advantages and disadvantages of the technique are discussed. This contribution is an extract of the lecture held in Erice (Sicily) in occasion of the “18th Course - Liquid crystal nanostructures and self-assembling: from organic electronics to metamaterials”, the 2nd School of the Italian Liquid Crystal Society. [ABSTRACT FROM AUTHOR]

Solid State 2H Nuclear Magnetic Resonance (NMR) spectroscopy was applied to the structural and orientational studies of a selectively labelled ‘de Vries’ liquid crystal compound. Measurements were performed at five values of the magnetic field, ranging from 4.70 to 18.80 T. The trend of the orientational order S and tilt angle θ of the 2H-labeled moiety in the SmA and SmC* phases at different magnetic fields confirms previous results and allows us to better characterize the SmA-SmC* transition. [ABSTRACT FROM PUBLISHER]

In this work the structure of the tilted TGBC* phase is investigated by means of the line-shape analysis of Deuterium NMR spectra. The case of a rod-like mesogen containing a (S)-2-methylbutyl-(S)-lactate unit in the chiral chain, whose acronym is HZL 7/*, is taken as a representative example for the large temperature range of stability of its tilted TGB* phases. By comparing the experimental and computed Deuterium NMR spectra several structural features can be extracted. For instance, the analysis of Deuterium NMR line-shapes put in evidence the occurrence of helical deformations due to the effect of the external magnetic field. [ABSTRACT FROM AUTHOR]

Several 2H NMR studies have been performed on two deuterium labelled banana-shaped liquid crystals, the 1,3-phenylene bis{4-4'-(11-undecenyloxy) benzoyloxy} benzoate (Pbis11BB) and its 4-chloro homologue (ClPbis11BB), in the isotropic, nematic and B2 phases.In this article, the state of the art of these studies is drawn and some new 2H NMR measurements on deuterated banana sub-units, namely the 3-(benzoyloxy)phenyl benzoate-d10 (BOB-d10) and its 4-chloro homologue (ClBOB-d10), used as small probes dissolved in two banana-shaped liquid crystals in the nematic phase are reported.As a general result, the orientational ordering properties of these sub-units are discussed in the frame of recent results obtained on the same banana-shaped liquid crystals dissolved in calamitic nematic solvents as well as in the bulk. [ABSTRACT FROM AUTHOR]

The behaviour of the 2 H NMR line-width throughout the whole mesophasic range of the ferroelectric liquid crystal “1-methylheptyl 4'-(4?-n-decyloxybenzoyloxy) biphenyl-4-carboxylate” (10B1M7) is here reported and discussed. Static Fringe Field NMR Diffusometry measurements from the isotropic to the anticlinic phase have been performed leading to a significant result concerning the tumbling diffusional coefficient (D ? ). These results have been compared to X-Ray measurements and 2 H NMR line-widths in order to explain the peculiar behaviour occurring at the transition between the ferroelectric (FLC) and the antiferroelectric (AFLC) liquid crystalline phases. [ABSTRACT FROM AUTHOR]

We investigated by 2 H NMR spectroscopy a ferroelectric liquid crystalline polysiloxane (poly11EB1M7- d 2 ) derived from the mesogen (+)( S ) 4-[4′-(1-methylheptyloxy)]biphenyl 4-(10-undecenyloxy)benzoate- d 2 (11EB1M7- d 2 ). The labelling on the phenyl fragment allowed us to study the orientational order of such unit. From the analysis of the deuterium lineshapes we could also determine the effect of the magnetic field on the mesogen alignment and the ferroelectric helix distortion. In particular, deuterium spectra showed a contribution due to aligned mesogens in addition to a "Pake-like" one. This was accounted for by considering isotropic distribution of helices, with possible helix distorsion. [ABSTRACT FROM AUTHOR]