Crystal-liquid crystal binary phase diagrams

Dayal, Pratyush; Matkar, Rushikesh A.; Kyu, Thein

doi:10.1063/1.2200688

Cited by 11 publications

(7 citation statements)

References 18 publications

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“…The single phase crystal (Cr 1 , Cr 2 ) and hexagonal columnar phase (t-Col h1 , Col h1 ) regions are observed at the compositions >90% and <10% HABET. Phase behavior of the blends containing columnar LC and crystalline constituents has been well-demonstrated experimentally and theoretically by Kyu et al − …”

Section: Resultsmentioning

confidence: 85%

Heat Transfer Organic Materials: Robust Polymer Films with the Outstanding Thermal Conductivity Fabricated by the Photopolymerization of Uniaxially Oriented Reactive Discogens

Kang

Park

Kim

et al. 2016

ACS Appl. Mater. Interfaces

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For the development of advanced heat transfer organic materials (HTOMs) with excellent thermal conductivities, triphenylene-based reactive discogens, 2,3,6,7,10,11-hexakis(but-3-enyloxy)triphenylene (HABET) and 4,4',4″,4‴,4'''',4'''''-(triphenylene-2,3,6,7,10,11-hexaylhexakis(oxy))hexakis(butane-1-thiol) (THBT), were synthesized as discotic liquid crystal (DLC) monomers and cross-linkers, respectively. A temperature-composition phase diagram of HABET-THBT mixtures was first established based on their thermal and microscopic analyses. From the experimental results, it was realized that the thermal conductivity of DLC HTOM was strongly affected by the molecular organizations on a macroscopic length scale. Macroscopic orientation of self-assembled columns in DLC HTOMs was effectively achieved under the rotating magnetic fields and successfully stabilized by the photopolymerization. The DLC HTOM polymer-stabilized at the LC phase exhibited the remarkable thermal conductivity above 1 W/mK. When the DLC HTOM was macroscopically oriented, the thermal conductivity was estimated to be 3 W/mK along the in-plane direction of DLC molecule. The outstanding thermal conductivity of DLC HTOM should be originated not only from the high content of two-dimensional aromatic discogens but also from the macroscopically oriented and self-assembled DLC. The newly developed DLC HTOM with an outstanding thermal conductivity as well as with an excellent mechanical sustainability can be applied as directional heat dissipating materials in electronic and display devices.

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Section: Resultsmentioning

confidence: 85%

Heat Transfer Organic Materials: Robust Polymer Films with the Outstanding Thermal Conductivity Fabricated by the Photopolymerization of Uniaxially Oriented Reactive Discogens

Kang

Park

Kim

et al. 2016

ACS Appl. Mater. Interfaces

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“…It is worth mentioning that an incompleteness of the classical phase diagrams for polymer-low MW substance and polymer-polymer systems, was also noted by Kyu et al [22][23][24] who extended the Flory theory to account for the possible cocrystallization of Dibutyl phthalate (DBP) of high-purity grade with T m D ¡35 C, T b D 340 C, refractive index of 1.4906, and density of 1.042 at 25 C, was used as a solvent.…”

Section: Introductionmentioning

confidence: 90%

Phase Diagrams Semicrystalline Polymer–Liquid Revisited: Isotactic Polypropylene-Dibutyl Phthalate and Other Systems

Mizerovskii

Pochivalov

Kudryavtsev

et al. 2015

Journal of Macromolecular Science, Part B

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The full phase diagram of an isotactic polypropylene (i-PP)-dibutyl phthalate (DBP) mixture is for the first time constructed by an optical method and discussed within the concept of semicrystalline polymers as microheterogeneous liquids with a threedimensional network structure. It is demonstrated that the liquidus in this and other polymer-solvent systems is not thermodynamically equivalent to the liquidus in low molecular weight (MW) mixtures. Qualitatively different thermal behavior of those two types of binary systems in the liquidus vicinity is corroborated by differential scanning calorimetry (DSC) experiments. In the former case, a liquid-solid transition resulting in the formation of polymer crystallites does not lead to separating the mixture into crystalline and amorphous phases. On cooling, the system remains macroscopically single phase until the low MW liquid can be fully dissolved in the amorphous regions of the polymer. The correct location of the corresponding borderline is crucially important for the microporous membrane formation via thermally induced phase separation (TIPS). It is also argued that the topology of a phase diagram polymer-low MW liquid does not depend on whether the polymer is amorphous or crystalline.

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“…A theoretical phase diagram of the mixtures exhibiting the crystal (Cr), smectic A (SmA), and nematic (N) phases has been established by employing a combined Flory-Huggins ( f FH ), Maier-Saupe/Maier-Saupe-McMillan ( f MS/MSM ), and phase field ( 22 In the Flory-Huggins theory, the enthalpic and entropic changes on mixing are derived in the context of the statistical lattice model where the respective constituents occupy a lattice with no specific interactions. The Maier-Saupe theory is based on a This journal is © The Royal Society of Chemistry 2015 mean field approximation.…”

Section: The Model Descriptionmentioning

confidence: 99%

Optically isotropic liquid crystal media formulated by doping star-shaped cyclic oligosiloxane liquid crystal surfactants in twin nematic liquid crystals

Kim

Park

et al. 2015

Soft Matter

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The formation of optically isotropic liquid crystal (LC) media has been investigated by doping the star-shaped LC molecular surfactants (SiLC) into the rod-shaped twin LC host molecules (DiLC). The experimental phase diagram was constructed on the basis of differential scanning calorimetry (DSC) and then a theoretical calculation was conducted through a combined Flory-Huggins (FH)/Maier-Saupe-McMillan (MSM)/phase field (PF) model to account for the experimental results. The phase diagram of the SiLC/DiLC mixtures revealed the broad coexistence regions such as smectic A + crystal (SmA1 + Cr2), liquid + crystal (L1 + Cr2), and liquid + nematic (L1 + N2) at the intermediate composition along with the narrow single phase crystal (Cr2), smectic (SmA1), and nematic (N2) regions. The morphologies and structures of these coexistence regions were further confirmed by polarized optical microscopy (POM) and wide-angle X-ray diffraction (WAXD). At the 80/20 SiLC/DiLC composition, the optical anisotropy was induced under an alternating current (AC) electric field above its isotropization temperature. The formation of an optically isotropic LC medium in mixtures of the SiLC molecular surfactants and nematic LC host may allow us to develop new electro-optical devices.

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Crystal-liquid crystal binary phase diagrams

Cited by 11 publications

References 18 publications

Heat Transfer Organic Materials: Robust Polymer Films with the Outstanding Thermal Conductivity Fabricated by the Photopolymerization of Uniaxially Oriented Reactive Discogens

Heat Transfer Organic Materials: Robust Polymer Films with the Outstanding Thermal Conductivity Fabricated by the Photopolymerization of Uniaxially Oriented Reactive Discogens

Phase Diagrams Semicrystalline Polymer–Liquid Revisited: Isotactic Polypropylene-Dibutyl Phthalate and Other Systems

Optically isotropic liquid crystal media formulated by doping star-shaped cyclic oligosiloxane liquid crystal surfactants in twin nematic liquid crystals

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