Behavior and properties of side chain thermotropic liquid crystal polymers

Dubois, Jean; Barny, P. Le; Mauzac, M.; Noël, Claudine

doi:10.1002/actp.1997.010480301

Cited by 23 publications

(12 citation statements)

References 200 publications

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“…Alpha-stepper ature results. This value is about one order of magnitude measurements have shown, that the thickness variation smaller than for some polymeric liquid crystals with over the area of the sheets is limited to a range of very high polarization [26]; on the other hand, it is about 5 mm. With pyroelectric investigations and the larger than the values found for some di erent elastomers help of additional thermal di usivity measurements, it [13].…”

Section: 32mentioning

confidence: 88%

Measurement of the pyroelectric response and of the thermal diffusivity of microtomized sections of 'single crystalline' ferroelectric liquid crystalline elastomers

Leister¹,

Lehmann²,

Weber³

et al. 2000

Liquid Crystals

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The pyroelectric response and the thermal properties of microtomized sections of 'singlecrystalline' ferroelectric liquid crystalline elastomers (FLCE) have been investigated. The microtomized sections were manufactured in the thickness range from 20 to 100 mm. The roughness of the surfaces due to the cutting process was investigated with an alpha-stepper and found to be in the range of about 5 mm. The thermal di usivity of the elastomer at di erent temperatures was determined by placing the sample on a pyroelectric substrate and measuring the pyroelectric signal of the substrate under appropriate conditions. From the pyroelectric current spectra, information about the spatial distribution of the polarization could be deduced. It was found to be constant except in a range also about 5 mm near the surface. From the combination of this result and that of the alpha-stepper measurements, the conclusion is drawn that the molecular orientation at the surface is destroyed due to the cutting process. The magnitude of the spontaneous polarization was calculated from the pyroelectric measurements at di erent temperatures, making use of the thermal di usivity values.

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Section: 32mentioning

confidence: 88%

Measurement of the pyroelectric response and of the thermal diffusivity of microtomized sections of 'single crystalline' ferroelectric liquid crystalline elastomers

Leister¹,

Lehmann²,

Weber³

et al. 2000

Liquid Crystals

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“…A review [49] of the thermotropic liquid crystalline side chain polymers dealt with the chemical structure, phase behavior, and ferroelectric and electro-optical properties of these polymers. Potential applications were indicated, such as nonlinear optics, pyroelectric detectors and display applications.…”

Section: Polymers With Special Propertiesmentioning

confidence: 99%

Trends in polymer chemistry 1997 Part 1: Pure research

et al. 1998

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“…Because the system is thermotropic, the mesogens undergo temperature-dependent phase transition from the nematic to isotropic phase at a temperature that depends not only on the particular mesogen but also on the cross-linking density. [5] By selecting appropriate functional groups for the mesogens and the cross-linkers, it is possible to create different materials that mechanically respond to heat, light, magnetic, or electric fields. This has led to the creation of SCLCEs for applications including mechanically tunable optical systems, forming small actuators or generators, and creating new types of displays.…”

Section: Introductionmentioning

confidence: 99%

Thermal characterisation of thermotropic nematic liquid-crystalline elastomers

et al. 2015

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Nematic liquid-crystalline elastomers (LCEs) are weakly cross-linked polymeric networks that exhibit rubber elasticity and liquid-crystalline orientational order due to the presence of mesogenic groups. Three end-on sidechain nematic LCEs were investigated using real-time synchrotron wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), and thermogravimetry (TG) to correlate the thermal behaviour with structural and chemical differences among them. The elastomers differed in cross-linking density and mesogen composition. Thermally reversible glass transition temperature, T g , and nematic-to-isotropic transition temperature, T ni , were observed upon heating and cooling. By varying the heating rate, T g 0 and T ni 0 were determined at zero heating rate. The temperature dependence of the orientational order parameter was determined from the anisotropic azimuthal angular distribution of equatorial reflections seen during real-time WAXS. Results show that the choice of cross-linking unit, its shape, density, and structure of co-monomers, all influence the temperature range over which the thermal transitions take place. Including multi-ring aromatic groups as cross-linkers increased the effective stiffness of the cross-linking, resulting in a higher glass transition temperature. The nematic-to-isotropic transition temperature increased in the presence of multi-ring aromatic structures, as either cross-linkers or mesogens, particularly when the multi-ring structures were larger than the low-molar-mass mesogen common to all three samples.

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Behavior and properties of side chain thermotropic liquid crystal polymers

Cited by 23 publications

References 200 publications

Measurement of the pyroelectric response and of the thermal diffusivity of microtomized sections of 'single crystalline' ferroelectric liquid crystalline elastomers

Measurement of the pyroelectric response and of the thermal diffusivity of microtomized sections of 'single crystalline' ferroelectric liquid crystalline elastomers

Trends in polymer chemistry 1997 Part 1: Pure research

Thermal characterisation of thermotropic nematic liquid-crystalline elastomers

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