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A recently developed crystallographic algorithm revealed an unexpected interwoven network structure in chiral thermotropic liquid crystals of achiral rodlike molecules. The two networks are homochiral in network geometry and molecular arrangement.

This paper characterizes the molecular mobility that triggers the cold crystallization abilities in 5'-(2,3-difluorophenyl)-2'-ethoxy-4-pentyloxy-2,3-difluorotolane (short name DFP25DFT) material by broadband dielectric spectroscopy (BDS). We analyze the properties of identified molecular motions by referring to the Vogel-Fulcher-Tammann (VFT) model for the structural α-process associated with molecular rotation in isotropic liquid and the Eyring and Starkweather approach for the thermally activated processes, β-process related to intramolecular movement in liquid and glassy state and emerging during cold crystallization α'-process ascribed to confined movements of molecules located adjacent to crystalline surfaces. To characterize the material, we employ single-crystal X-ray diffraction, differential scanning calorimetry (DSC), adiabatic calorimetry, and polarizing optical microscopy (POM), while we utilize molecular mechanics simulations (MM2) to explore molecular flexibility. Our study focuses on inter- and intramolecular interactions that determine the cold-crystallization tendency. We demonstrate that the solidification path is controlled by the fragility of the system, the dipole-dipole attraction, and the intramolecular dynamics. The study of cold crystallization kinetics under isothermal conditions reveals the complexity of the process: the formation of two crystalline phases, Cr2 and Cr3, proceeding in different modes. This feature discloses the possibility of switching the crystal growth between three- and two-dimensional in the cold-crystallization process driven by different mechanisms.

In this study, we apply differential scanning calorimetry (DSC) and polarizing microscopy (POM) to elucidate the interplay of crystallization mechanisms controlling the tendency for melt and cold c...

This work was supported in part by JSPS Grant-in-Aid for Scientific Research on Innovative Areas “Discrete Geometric Analysis for Materials Design” (JP20H04629) and Grant-in-Aid for Scientific Research (B) (JP21H01046).

The relationship between the membrane bending modulus (κ) and compressibility modulus (K(A)) depends on the extent of coupling between the two monolayers (leaflets). Using neutron spin echo (NSE) spectroscopy, we investigate the effects of n-alkanes on the interleaflet coupling of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers. Structural studies with small-angle X-ray and neutron scattering (SAXS and SANS) showed that the bilayer thickness increased with increasing n-alkane length, while NSE suggested that the bilayers became softer. Additional measurements of the membrane thickness fluctuations with NSE suggested that the changes in elastic moduli were due to a decrease in coupling between the leaflets upon addition of the longer n-alkanes. The decreased coupling with elongating n-alkane length was explained based on the n-alkane distribution within the bilayers characterized by SANS measurement of bilayers composed of protiated DPPC and deuterated n-alkanes. A higher fraction of the incorporated long n-alkanes were concentrated at the central plane of the bilayers and decreased the physical interaction between the leaflets. Using NSE and SANS, we successfully correlated changes in the mesoscopic collective dynamics and microscopic membrane structure upon incorporation of n-alkanes.

Heat capacities of three ketohexoses in monosaccharides, D -fructose, D -psicose, and D -tagatose, were measured for crystalline states in the temperature range from 13.8 K to 330 K by adiabatic calorimetry. Their standard thermodynamic functions were estimated from the measured molar heat capacities. A spectral analysis using Kieffer’s model was applied to the heat capacities to rationalize the relation among them in terms of intra- and intermolecular hydrogen bond in crystal.

Control over the stacking patterns in 2D molecular assemblies is demonstrated using chemical modification. A target system is a hydrogen-bonded cocrystal (2:1) composed of 2-pyrrolidone (Py) and chloranilic acid (CA) (PyCA). X-ray crystallography showed that weak intersheet interactions give rise to a variety of metastable overlapping patterns comprised of the 2D assemblies mainly formed via hydrogen bonds, affording reversible and irreversible structural phase transitions. We prepared cocrystals of Py and anilic acids bearing different halogens, in which 2D assemblies isostructural with those observed in PyCA exhibit various overlapping patterns. The order of stability for each overlapping pattern estimated using calculations of the intermolecular interactions did not completely coincide with those indicated by our experimental results, which can be explained by considering the entropic effect: the molecular motion of Py as detected using nuclear quadrupole resonance spectroscopy.

A recent intriguing finding that a helical network arrangement forms the bicontinuous cubic phase is attracting great attention for the possibility of new routes to asymmetric synthesis by achiral molecules. However, the design of the molecular structure for the cubic phase is still unrevealed. In this work, a nonsymmetric core molecule with larger naphthalene and smaller benzene moieties at each side of the central linkage and the same disiloxanyldecyloxy terminal at both terminals is shown to be the first example of molecule forming both single-layered and double-layered core assembly modes in the Ia3d phase as a single molecule system. The molecule forms the former mode at high temperatures as a thermodynamically stable phase, similarly to the symmetric naphthalene core system, whereas, on cooling below a temperature (∼350 K), a metastable Ia3d phase forms a double-layered core state down to room temperature, which is common to the benzene core system. As another effect of the nonsymmetric core, the cubic phase is maintained at room temperature for more than 100 days with slight distortion. Infrared spectral studies and quantum chemical calculations suggested the easy transformation between the two core assembly modes. The core nonsymmetry can be a versatile fine-tuning of the core assembly mode and phase stability for the cubic phase molecules.

Although the transition between a bilayer and an interdigitated membrane of a surfactant and lipid has been widely known for long, its mechanism remains unclear. This study reveals the transition mechanism of a cationic surfactant, dioctadecyldimethylammonium chloride (DODAC), through experiments and theoretical calculations. Experimentally, the transition from the interdigitated to bilayer structure in the gel phase of DODAC is found to be induced by adding hydrophobic molecules such as n-alkane and its derivatives. Further addition induces a different transition to another bilayer phase. Our theory, considering the competition of the electrostatic interaction between cationic headgroups and the hydrophobic interaction emerging at the alkyl-chain ends exposed to water, reproduces these two phase transitions. In addition, changes in alkyl-chain packing in the membranes at these transitions are reproduced. The underlying mechanism is that the interdigitated membrane is formed at a small additive content due to electrostatic repulsion. As the energetic disadvantage with respect to the hydrophobic interaction becomes dominant as the content increases, the transition to the bilayer occurs at a specific content. The bilayer-bilayer transition at a higher content is induced by the change in the balance of these interactions. Based on a similar concept, we suggest the mechanism of the additive-induced bilayer-interdigitated transition of phospholipids, i.e., neutrally charged (zwitterionic) surfactants.

This article presents the molecular dynamics and solidification behavior of a 2,3-difluoro-4-propylphenyl 2,3-difluoro-4-(4-pentylcyclohexyl)benzoate nematic liquid crystal (5C4FPB3) observed by broadband dielectric spectroscopy (BDS) and differential scanning calorimetry (DSC). Polarized optical microscopy (POM) is also performed to confirm the phase transition temperatures. Our investigation reveals rare crystallization of the orientationally disordered crystal (ODIC) phase from the nematic phase and a glass transition of the crystal at cooling rates higher than 1 K min−1. The deconvolution of the dielectric spectra with derivative techniques is necessary because of the complex molecular dynamics in the crystalline phase. The BDS method enables us to capture the relaxation processes reflecting pre-crystallization molecular movements. The kinetics of nonisothermal crystallization is studied using the Ozawa, Mo, and isoconversional methods. The present studies suggest that the dominant factor of the crystal growth mechanism depends on the cooling rate. Two types of crystallization mechanisms are identified at cooling rates lower and higher than 5 K min−1. We design a diagram with crystallization and glass transition borders against the cooling rates. Estimations show that crystallization of the present compound can be bypassed at cooling rates higher than 78 kK min−1, at which a glass transition of the nematic phase occurs. We show various scenarios of the molecular order and the crystallization mechanism designed based on the process rate.

1,2-Bis(4′-n-alkoxybenzoyl)hydrazine [BABH(n), n is the number of carbon atoms in the alkyl chain] exhibits two different Iad cubic phases depending on the chain length (5 ≤ n ≤ 13 and 15 ≤ n ≤ 22). The molecular packing modes, not only of molecular cores but also of alkyl chains, are investigated through a maximum entropy method (MEM) and an analysis of the chain-length dependence of the body diagonal of the unit cell. The analyses revealed the difference in molecular packing. The short-chain Iad structure of BABH(n) (5 ≤ n ≤ 13) is constructed by single-layered core motifs and bilayers of alkyl chains, in which the orientation is tilted from the normal to the layer. The long-chain Iad structure (15 ≤ n ≤ 22) is formed by double-layered core motifs and monolayers of alkyl chains, in which the orientation is normal to the layer. Based on the molecular packing modes, the reentrant behavior between the two Iad phases was clarified. It was revealed that the alkyl chains of BABH(n) molecules play an essential role in the formation and stability of the two Iad structures.

Optical switching between one-dimensionally ordered layered smectic C (SmC) and three-dimensionally periodic bicontinuous cubic (Cubbi) liquid-crystalline (LC) phases is a fascinating challenge bec...

To elucidate the relationship between prototropic tautomerism and the cold crystallization phenomenon, o-hydroxy aryl Schiff base compounds derived from three different toluidine isomers were examined. Comparing their thermal behavior, we confirmed that cold crystallization occurred to give a different crystalline phase compared to the initial state. To elucidate the mechanisms of the cold crystallization of the materials, their thermal, structural, and energetic properties were investigated. The DFT calculation of the molecules in their OH- and NH-forms suggested that the NH-form has higher molecular flexibility, which may prevent normal crystallization upon cooling, compared to the OH-form. Spectroscopic analyses implied that the molecules are present as a mixture of the OH- and NH-forms, and that they efficiently crystallize when a preferable OH/NH ratio is achieved. For this molecular system, we concluded that the equilibrium between NH- and OH-forms controls the supercooling of the liquid as well as ...

Photoinduced changes in the upper critical solution temperature (UCST) were investigated for polymer solutions in an azobenzene-doped liquid crystal solvent. The UCST of poly(methyl methacrylate) (PMMA) and polystyrene (PS) solutions dropped upon irradiation with UV light, which induces trans-cis photoisomerization of the doped azo dye. In the case of PMMA solutions, the photoinduced drop in UCST was significantly larger than that expected from previous studies using azo-based polymers and common solvents. Moreover, the UCST of PS solutions also decreased under photoirradiation, in a direction opposite to that expected from the contribution of polarity. X-ray diffraction data of the solvent suggest that the decreased intermolecular interaction in the solvent (i.e. larger distance between the solvent molecules) is responsible for the photoresponsive behavior of the UCST. The proposed mechanism is consistent with the Flory-Huggins theory. Using such photoresponses in the UCST, the isothermal transition between 2-phase and 1-phase states by photoirradiation was demonstrated.

The complex polymorphism and vibrational dynamics of three glass-forming single-phenyl-ring alcohols (with and without fluorine atoms) have been studied by complementary methods. Glass of isotropic...

The formation of globular associate on cooling, which was previously claimed on the basis of small dielectric constant, is supported through measuring X-ray scattering from dicyclohexylmethanol (DCHM). Radial distribution function of the DCHM molecules exhibits strong temperature dependence between 65 °C and 130 °C in contrast to a little change in that of tricyclohexylmethanol (TCHM), which is similar to DCHM but essentially non-associating in experimental conditions (95–160 °C).

Effects of nine incorporated n-alkane derivatives on molecular packing and phase behavior of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers were investigated using wide angle X-ray dif...

1,2-Bis(4'-n-alkoxybenzoyl)hydrazine [BABH(n), n is the number of carbon atoms in the alkyl chain] exhibits two different Ia3[combining macron]d cubic phases depending on the chain length (5 ≤n≤ 13 and 15 ≤n≤ 22). The molecular packing modes, not only of molecular cores but also of alkyl chains, are investigated through a maximum entropy method (MEM) and an analysis of the chain-length dependence of the body diagonal of the unit cell. The analyses revealed the difference in molecular packing. The short-chain Ia3[combining macron]d structure of BABH(n) (5 ≤n≤ 13) is constructed by single-layered core motifs and bilayers of alkyl chains, in which the orientation is tilted from the normal to the layer. The long-chain Ia3[combining macron]d structure (15 ≤n≤ 22) is formed by double-layered core motifs and monolayers of alkyl chains, in which the orientation is normal to the layer. Based on the molecular packing modes, the reentrant behavior between the two Ia3[combining macron]d phases was clarified. It was revealed that the alkyl chains of BABH(n) molecules play an essential role in the formation and stability of the two Ia3[combining macron]d structures.

Phase behaviors of two homologous binary systems of 4-alkyl-4′-cyanobiphenyl (nCB, n being the number of carbon atoms in the alkyl chain) and 4-alkoxy-4′-cyanobiphenyl (nOCB) were investigated. Their phase diagrams were drawn against an averaged chain length, n*. The phase boundary curves between neamtic (N) and smectic Ad (SmAd) phases in nCB/mCB (n = 3–6; m = 8, 9) binary systems were classified into four depending on four combinations of even- and odd-numbered n and m; even/even, odd/even, even/odd, and odd/odd. The similar odd–even effect was confirmed for nOCB/mOCB (n = 5, 6; m = 8, 9) binary systems. To elucidate the odd–even effect on the phase diagrams, the SmAd structures were investigated through an analysis of n (n*) dependence of the layer spacing of the SmAd structure, dSmAd, of neat nCB (n = 8–10), neat nOCB (n = 8–10), and nCB/8CB (n = 0–7) binary mixtures. The odd–even effect, the behavior of 0CB/8CB system, and the difference between nCB and nOCB were clarified based on their SmAd structures.

The reported layer spacings (dsmectic) of six homologues of mesogens exhibiting orthogonal smectic phases (SmE, SmB, and SmA phases) are reexamined. The slopes of the linear dependences on chain length (n, the number of carbon atoms in the hydrocarbon chain) are clearly categorized into two groups: 1.9 A (CH2)−1 and 1.4 A (CH2)−1. It is clarified that in the former the molecules take a rod-like form (rod-form; category-I), whereas in the latter the molecules are bent around the connection between the core and chain moieties (bent-form; category-II). The average relative positions of adjacent molecules within the smectic structures are deduced from the intercept of the linear functions of dsmectic against n. The relation between and the features of molecules belonging to the two categories are discussed for molecular design of functional smectic liquid crystals.

Single-crystal structural analyses and heat capacity measurements were performed on two Schiff base liquid crystal compounds, 5CBAA (4-chlorobenzylidene-4′-pentyloxyaniline) and 5ABCA (4-pentyloxybenzylidene-4′-chloroaniline). The alkyloxy-chain of a 5CBAA molecule was conformationally ordered in the crystal at room temperature. While that of 5ABCA was partially disordered in the room temperature phase but ordered in a low-temperature phase at 100 K. The structural phase transition involving the disordering of the conformation was observed at 107 K in the heat capacity of 5ABCA. Both compounds showed two liquid crystalline phases, SmBCr and SmAd. The net entropy change associated with the chain disordering was essentially the same in them despite the difference in the orientation of their central –CHN– moiety. The layer-spacings of SmBCr and SmAd phases were analyzed for their chain-length dependence in both series of mesogens (nCBAA and nABCA), as well as in the case of nBBAA (4-bromobenzylidene-4′-alkyloxyaniline). The results reveal that these smectic structures are composed of alternately stacked core- and chain-layers with an antiparallel arrangement of cores and a bent-form of molecules.

Effects of monovalent and monatomic salts on lamellar repeat distances d of nonionic surfactants (monomyristolein and $${\mathrm {C_{12}E_{2}}}$$ ) are investigated using small-angle X-ray diffraction. The lamellar repeat distances (sum of thicknesses of a bilayer and a sandwiched water layer) increase with increasing salt concentration with a strong anion dependence (Br $$^->$$ Cl $$^- $$ ). The increase of the thickness of the water layer is found to dominate the increase in d. Since the anion dependence is inconsistent with the ion dependence of the strength of the primary hydration, we reported previously (Hishida et al. J Chem Phys 142:171101, 2015), the hydration force classically considered is not the origin of the increase in d. This means the increase in d cannot be explained by the existing model of the forces between neutrally charged bilayers. The temperature dependence of d also supports the necessity for a new mechanism of the effect of ions. The new mechanism seems to be related to the water structure beyond the primary hydration water, i.e., the secondary hydration water, which depends on the ion species.

Greigite, a ferrimagnetic iron sulfide Fe(II)Fe(III)2S4, is thought to have played an essential role in chemical evolution leading to the origin of life. Greigite contains a [4Fe–4S] cluster-like structure and has been synthesized in the laboratory by liquid-state reactions. However, it is unclear how greigite can be synthesized in nature. Herein, we show that greigite is synthesized by the solid–gas reaction of Fe(III)-oxide-hydroxides and H2S. We discovered that the hyperthermophilic hydrogenotrophic methanogen Methanocaldococcus jannaschii reduced elemental sulfur, and the resulting sulfide generated greigite from hematite. The time course and pH dependence of the reaction respectively indicated the involvement of amorphous FeS and H2S as reaction intermediates. An abiotic solid–gas reaction of hematite and H2S (g) under strictly anaerobic conditions was developed. The solid–gas reaction fully converted hematite to greigite/pyrite at 40–120 °C within 12 h and was unaffected by the bulk gas phase. Similar abiotic reactions occurred, but relatively slowly, with aqueous H2S in acidulous liquids using hematite, magnetite, or amorphous FeO(OH) as starting materials, suggesting that greigite was extensively produced in the Hadean Eon as these Fe(III)-oxide-hydroxides were shown to be present or routinely produced during that era. Surprisingly, the obtained greigite induced methanogenesis and growth of hydrogenotrophic methanogens, suggesting that the external greigite crystals enhanced reactions that would otherwise require enzymes, such as [4Fe–4S] cluster-harboring membrane-bound hydrogenases. These data suggested that the greigite produced by the solid–gas and solid–dissolved gas reactions was bioactive.

Possible influence of the nanoscale rippled structure at a lipid vesicle surface on macroscopic physical properties of their dispersions was investigated. The macroscopic shear viscosity of highly concentrated lipid vesicle dispersions dramatically decreased under the conditions in which the ripple pattern was formed on surfaces. The decrease in the shear viscosity is suggested to originate in the prevention of aggregation of vesicles by mismatch of static rippled structures at vesicle surfaces.

We investigate the phase separation of a ternary lipid bilayer including n-alkane and construct the ternary phase diagram. When a certain proportion of a long n-alkane is mixed with a binary mixture of lipids, which exhibit the disordered liquid-crystalline phase and the ordered gel phase at room temperature, we observed the characteristic morphology of bilayers with phase separation. The ordered bilayer forms flat and rigid domains, which is connected or rimmed with flexible domains in the disordered phase. The asymmetric emergence of the phase separation region close to the ordered phase side is interpreted based on the almost equal distribution of the n-alkane to the ordered and disordered phase domains.

Phase transitions in the crystalline state of chiral sorbose were examined using precise heat capacity calorimetry and X-ray crystallography. The calorimetry established heat capacity below room temperature. Besides the known transition (main transition) at 199.5 K, the calorimetry detected plural thermal anomalies assignable to new phase transitions (around 210 K) and a glass transition (at ca. 120 K). The X-ray diffraction at low temperatures established the crystal structure of the lowest temperature phase. The identification of the broken symmetry upon the main transition solves an apparent contradiction that the structural disorder reported previously does not contribute seemingly to the symmetrization.

Assuming the twisted arrangement of rodlike molecules as the origin of the chirality as in the existing model, a new model of the molecular arrangement in the cubic "Im3m" phase is proposed. The adoption of a basic structure different from that assumed in the existing model resolves most difficulties of the model including the random placement of defects concerning the sense of twist.

The introduction of oligodimethyl siloxane segments at the termini of the alkyl tails has been employed to stabilize the bicontinuous cubic (Cub(bi)) phase of a chain-core-chain type molecule having a 1,2-bis(benzoyl)hydrazine central core with two chains attached at the 4' position of each benzoyl moiety. In this study, three silylated molecules, bis-C10Si2, bis-C10Si3, and C10Si2-C8C=C, were synthesized, where "CnSim" represents the number of carbon and silicon atoms in the chain and "bis" indicates the two chains being the same, whereas the last one is asymmetric with respect to the core. The phase behaviors were examined by using polarized optical microscopy, differential scanning calorimetry, and X-ray diffraction techniques. All three compounds form Cub(bi) phases and their syntheses were compared including their parent compound bis-C18. It was clearly revealed that the introduction of oligodimethyl siloxane segments effectively suppresses the crystallization at low temperatures, and as a result stabilizes the Cub(bi) phases, in an extreme case down to room temperature. The semi-quantitative analyses in terms of lattice constant and three-dimensional electron density map help us to better understand the self-assembly process in the Cub(bi) phases. The study also revealed that the introduction of oligodimethyl siloxane segments is not only an alternative for the hydrocarbon segment but also is able to provide a versatile design strategy for obtaining stable Cub(bi) phases.

Mirror symmetry breaking was observed by mixing of equimolar amounts of two gyroid phase-forming achiral molecules, one having a short and the other with a long tail. This fact indicates the importance of a critical chain length for the appearance of the chiral bicontinuous cubic (Cubbi) phase. It also demonstrates that the molecular-level mobility is closely connected to the formation and stabilisation of those Cubbi phases.

Two coordination isomers, i.e., square planar and pseudo-tetrahedral forms of the title compound, were crystallographically identified and discussed in relation to their thermal behavior revealed b...

Landau expansion of free energy assuming dual instabilities for the nano-segregated SmA phase is analyzed. In addition to known phase sequences (on cooling, disordered isotropic liquid → nematic phase → smectic phase, and disordered isotropic liquid → smectic phase), a new sequence (disordered isotropic liquid → density wave with subsidiary nematic order → smectic phase) and the existence of a critical point are demonstrated in the case where the instability for density wave formation occurs at a higher temperature.

Single-crystal structural analyses and heat capacity measurements were performed on two Schiff base liquid crystal compounds, 5CBAA (4-chlorobenzylidene-4'-pentyloxyaniline) and 5ABCA (4-pentyloxybenzylidene-4'-chloroaniline). The alkyloxy-chain of a 5CBAA molecule was conformationally ordered in the crystal at room temperature. While that of 5ABCA was partially disordered in the room temperature phase but ordered in a low-temperature phase at 100 K. The structural phase transition involving the disordering of the conformation was observed at 107 K in the heat capacity of 5ABCA. Both compounds showed two liquid crystalline phases, SmB

To test metal complexes as potential compounds for heat-storage materials, two Schiff-base Ni(II) complexes derived from two differently N-substituted toluidine isomers were examined. Comparing the behavior with that of a similar complex previously reported, it was found that the cold crystallization was realized in polymorphic complexes. The activation energy for crystallization estimated by using differential scanning calorimetry was well correlated to the ease of supercooling necessary for the cold crystallization. DFT calculations of molecular energy suggested that the cold crystallization phenomenon is closely related to a molecular flexibility that prevents normal crystallization during cooling. The molecular flexibility controls the ease in the supercooling of liquid and the nucleation–growth process of crystallization by altering the activation energy for crystallization.

Phase transition behavior of 1,2-bis(4′- n -hexyloxybenzoyl)hydrazine (BABH(6)) was studied by differential scanning calorimetry (DSC) and polarizing microscopy. While the DSC trace above melting temperature is consistent with the existing report, it is not for crystalline states. A number of tiny and spiky anomalies was observed in the first cooling run whereas the number of anomalies decreases, and finally disappeared in repeated runs. Microscopic observation revealed that the tiny and spiky anomalies arise from collapsing of crystals. When the sample was cooled from the cubic phase (430 K), the tiny and spiky anomalies revived on the cooling process, which can be ascribed to the liquid-crystallinity of the cubic phase.

The appearance of reentrant nematic phase was identified in nCB/8CB (n = 1–6) binary mixtures using differential scanning calorimetry, small-angle X-ray diffraction and polarising microscopy with photomonitor. Phase diagrams can roughly be unified if plotted against the average number of alkyl chain length. Distinction was recognised for the phase boundaries between nematic and smectic A phases of even and odd n of the minor component nCB. The character of 8CB as ‘SmA former’ is briefly discussed.

The phase behaviour of the thermotropic cubic mesogen 1,2-bis(4′-n-hexyloxybenzoyl)hydrazine [BABH(6)] was investigated under pressure up to about 55 MPa using a polarising optical microscope equipped with a high-pressure optical cell. BABH(6) shows the crystal (Cr)–cubic (Cub)–isotropic liquid (I) phase transition at ambient pressure on heating. The smectic C (SmC) phase was induced above 32 MPa, showing the unusual phase sequence of Cr–Cub–SmC–I, similar to those in BABH(n) (n = 8–10). The boundary between the Cub and SmC phases exhibited a negative slope dT/dP of about –1.0 oC MPa−1.

Through thermodynamic, spectroscopic, and structural studies, the molten state of the alkyl chain in SmE phase, which is the liquid-crystalline mesophase closest to an ordered crystalline phase, ha...

Thermodynamic and diffraction analyses were performed to establish the phase diagram for a binary system between 4-n-nonyl-4'-isothiocyanatobiphenyl (9TCB) and n-nonane. The swollen SmE structure is identified in the binary system. Upon swelling, a characteristic two-dimensional herringbone array is maintained whereas the layer spacing of SmE structure increases with the content of n-nonane. Considering the difficulties in explaining the experimental findings based on the traditional model of SmE structure, a new model, lamellar with two types of sublayers consisting of aromatic core and alkyl chain moieties, is proposed.

Nonmonotonous temperature dependence, which suggests formation of closed oligomer(s) via hydrogen-bonds, is detected in heat capacity and dielectric constant of the title compound in the liquid sta...