Temperature dependence of the enthalpy and the heat capacity of the liquid-crystal octylcyanobiphenyl (8CB)

Thoen, Jan; Marynissen, Heleen; Dael, W. Van

doi:10.1103/physreva.26.2886

Cited by 263 publications

(132 citation statements)

References 56 publications

Supporting

Mentioning

119

Contrasting

Order By: Relevance

“…Currently, there are two possibilities. The ''classical'' ASC implementation will not be discussed here, as these instruments are difficult to operate and require rather large samples (typically 0.5 g or more), but they were very successful in high-resolution studies of phase transitions [29,30,36]. The successor of the classical ASC is the Fig.…”

Section: Pascmentioning

confidence: 99%

“…The adiabatic scanning calorimeter allows the determination of the same parameters as a DSC, combined with a direct measurement of the enthalpy curve h(T), but it does not suffer from the phase transition deformation because of a fundamentally different measurement principle [29][30][31][32]. In adiabatic scanning calorimetry (ASC), the sample is heated by a controlled, constant amount of power.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A new calorimetric technique for phase change materials and its application to alkane-based PCMs

Duponchel

Longuemart

Glorieux

et al. 2016

Mater Renew Sustain Energy

View full text Add to dashboard Cite

The correct determination of the phase transition behaviour of phase change materials (PCMs) is paramount for assessing their application potential. In this work, the merits of a novel calorimetric technique, Peltierelement-based adiabatic scanning calorimetry (pASC), for PCM characterisation are investigated, especially in comparison with the commonly-used differential scanning calorimeter (DSC). A comparative study of two alkanebased PCMs, the commercial mixture RT42 and the pure alkane tricosane (C23) with these two techniques shows that pASC provides data at much higher resolution than DSC, due to its operation in thermodynamic equilibrium. Specifically the rate-dependence and deformation that is inherent to DSC experiments is absent in pASC. In addition, the enthalpy of the PCM is directly obtained. pASC results easily conform to the accuracy limits that are proposed in literature for the transition temperature and storage capacity of PCMs.

show abstract

Section: Pascmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A new calorimetric technique for phase change materials and its application to alkane-based PCMs

Duponchel

Longuemart

Glorieux

et al. 2016

Mater Renew Sustain Energy

View full text Add to dashboard Cite

show abstract

“…For instance, a reasonable fit could be reached for α = 0.5-0.11, with a flat minimum around 0.4 for a specific heat [4,42,43]. This uncertainty can be related to the minute scale of anomalies, their limited range of appearance (T -TI_N < 4 K) and the discontinuity of the I-N transition.…”

Section: Introductionmentioning

confidence: 99%

“…However, experiments clearly show the pretransitional anomaly of physical properties associated with the critical exponent α [4,[38][39][40][41][42][43][44][45][46] where p(T) and cp(T) are the density and the specific heat respectively. Coefficients di, αi, D, and A denote amplitudes.…”

Section: Introductionmentioning

confidence: 99%

The Fluid-Like and Critical Behavior of the Isotropic-Nematic Transition Appearing in Linear and Non-linear Dielectric Studies

2000

View full text Add to dashboard Cite

A short review of literature and the authors' experimental results for the pretransitional behavior in the isotropic phase of nematogens is given. The paper also presents new results of non-linear dielectric effect and dielectric permittivity measurements in the broad temperature range. Results obtained show significant advantages of non-linear dielectric effect and dielectric permittivity for studying pretransitional properties in liquid crystalline materials. The paper contains a comprehensive comparison of the experiment with predictions of the mean-field model and the fluid-like description. The presented analysis strongly supports the image of the isotropic phase as a complex liquid resulting from vicinity of the fluid-like, "nematic-isotropic", critical point.

show abstract

“…Among the various characterization methods, the ac calorimetric method is the most powerful and commonly used technique for the thermal characterization of liquid crystals [20][21][22]. Photoacoustic effect, mirage effect and photon transmission methods are some of the very recently introduced methods for the phase transition studies in liquid crystals [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Use of photoacoustic effect for the detection of phase transitions in liquid crystal mixtures

George¹,

Vallabhan²,

Nampoori³

et al. 2000

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Abstract. We report on a laser induced photoacoustic study of the nematic-to-isotropic transition in certain commercial nematic liquid crystal mixtures, namely BL001, BL002, BL032 and BL035. A simple analysis of the experimental data using the Rosencwaig-Gersho theory shows that the heat capacities of all these compounds exhibit a sharp peak as the temperature of the sample is varied across the transition region. Also, substantial differences in the photoacoustic signal amplitudes in nematic and isotropic phases have been noticed for all the mixtures. The increased light scattering property of the nematic phase may be the reason for the enhanced photoacoustic signal amplitude in this phase.

show abstract

Temperature dependence of the enthalpy and the heat capacity of the liquid-crystal octylcyanobiphenyl (8CB)

Cited by 263 publications

References 56 publications

A new calorimetric technique for phase change materials and its application to alkane-based PCMs

A new calorimetric technique for phase change materials and its application to alkane-based PCMs

The Fluid-Like and Critical Behavior of the Isotropic-Nematic Transition Appearing in Linear and Non-linear Dielectric Studies

Use of photoacoustic effect for the detection of phase transitions in liquid crystal mixtures

Contact Info

Product

Resources

About