Gel-liquid Crystalline Research Articles

Controlling the formation of ionic complex vesicles through double-tailed surfactants.

Liposomes are often used in cosmetics since they are naturally derived and have excellent texture enhancing capabilities. However, when preparing them by using phospholipids with unsaturated acyl groups, they easily suffer from oxidative degradation. Accordingly, hydrogenated phospholipids are preferred, however, it is difficult to prepare stable liposomes due to its high gel-liquid crystalline phase transition temperature. On the other hand, although dialkyl dimethyl ammonium type cationic surfactants are widely known to form vesicles, they have rarely been used for skincare products except for water-in-oil type emulsion creams stabilized by organically modified clay minerals. We decided to overcome all of the problems above through ionic complex vesicles formed by double-tailed cationic and anionic surfactants. Distearyl dimethyl ammonium chloride (DSAC) and sodium dilauramidoglutamide lysine (DLGL) were selected as cationic and anionic surfactants, respectively. Differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SWAXS) measurements were performed to confirm the DSAC/DLGL/water ternary phase diagram. Newly developed ionic complex vesicle formation was confirmed by cryogenic transmission electron microscopy (cryo-TEM). The adsorbed cosmetic film structure on the skin invivo was evaluated through the polarized infrared external reflection (PIR-ER). Finally, a cosmetic lotion formula was developed and the vesicle size was determined by dynamic light scattering (DLS). DSC and SWAXS data indicated that stable vesicles could be obtained at a molar ratio of DLGL to DSAC = 6:4. At this molar ratio, multi lamellar vesicles with diameters less than 100 nm were observed through cryo-TEM. PIR-ER data revealed that the developed vesicles formed a highly perpendicular orientation to the human skin surface. We have succeeded in formulating a cosmetic lotion containing developed vesicles with a mean diameter of 63.2 nm, which was stable over 1 month at 0, 37, and 50°C. Our newly developed vesicles can be easily obtained through a coagulation process. Also, the adsorbed film structure supported by PIR-ER experiments implies that the developed lotion has an excellent texture that is the same as cosmetic lotions containing liposomes. Therefore, it's possible that this ionic complex vesicle could take the place of liposomes.

Structural Analyses of Polysaccharides Extracted from Cyanobacterial Extracellular Gels and Oriented Liquid Crystalline Microfiber Processing by Poly(vinyl alcohol)-Assisted Electrospinning.

Sacran is a supergiant cyanobacterial polysaccharide that forms mesogenic supercoil rods that exhibit liquid crystalline (LC) gels at deficient concentrations of around 0.5 wt%, and has several bioactive stimuli-responsive functions. Here, we attempted to form oriented microfibers of sacran by electrospinning, following structural analyses of the sacran rods. A heterogeneous acid-hydrolysis method using a protonated cation-exchange resin was adopted to examine the short-time exposition of concentrated acid to sacran rods. From the supernatant, the oligomeric fraction that was soluble in water and methanol was isolated. The oligomeric fraction had a main sugar ratio of α-Glc:β-Glc:α-Xyl:β-Xyl:α-Rha of 2:5:1.5:1.5:4 (Glc:Xyl:Rha = 7 (=4 + 3):3:4), and it was speculated that the sacran structure includes rhamnoglucan and xyloglucan (4:3), which are generally rigid enough to exhibit LC. To make oriented microfibers of LC sacran, solubility testing was performed on sacran to find good new solvents of polyhydroxy alcohols such as ethylene glycol, 1,2-propanediol, and glycerol. The oriented film was prepared from a sacran aqueous solution where calcium compound particles deposited on the film are different from polyhydroxy alcohol solutions. Although sacran could not form microfibers by itself, polymer composite microfibers of sacran with poly(vinyl alcohol) were prepared by electrospinning. Cross-polarizing microscopy revealed the molecular orientation of the microfibers.

Metal-Assisted Injection Spinning of Ultra Strong Fibers from Megamolecular LC Polysaccharides.

The molecular orientation of liquid crystalline (LC) hydrogels has the potential to induce a range of functionalities that can deliver great mechanical strength. Sacran is a supergiant LC polysaccharide isolated from the cyanobacterium Aphanothece sacrum with a high amount of anionic functional groups such as sulfates and carboxylates. In this article, ultra-strong sacran hydrogels and their dried fibers were produced by cross-linking under injection flow with trivalent metal ions such as Al3+, Cr3+, Fe3+, In3+, and rare-earth metal ions such Er3+ and Sr3+. Crossed-polarizing microscopy and X-ray diffraction imaging revealed a uniaxial molecular orientation in the LC gel fiber, resulting in outstanding mechanical characteristics.

Evaluation of preclinical efficacy of apremilast-loaded liquid crystalline nanoparticulate gel in amelioration of atopic dermatitis

Apremilast is a phosphodiesterase-4 inhibitor currently under investigation for managing atopic dermatitis, but it is associated with poor physicochemical properties, majorly affecting its bioavailability. To improve the topical delivery, we have encapsulated apremilast into the liquid crystalline nanoparticles and evaluated its preclinical efficacy against atopic dermatitis. The liquid crystalline nanoparticles were manufactured by the melt emulsification method followed by probe sonication. The prepared nanoparticles were evaluated for particle size, zeta potential, encapsulation efficiency and in vitro release. Further, the apremilast liquid crystalline nanoparticles were loaded into the gel base by magnetic stirring. The gel formulation was evaluated for viscosity, textural profile, drug content, ex vivo permeation, and retention in mice skin. The preclinical efficacy of optimized gel formulation was assessed in 2,4-dinitrochlorobenzene induced atopic dermatitis in mice model followed by histopathological examination of skin sections. The apremilast was successfully loaded into the liquid crystalline nanoparticles with an average particle size of 180 ± 0.45 nm and entrapment efficiency of 89.42 ± 4.27 %. The optimized nanoparticles were successfully loaded into gel base showing pseudoplastic shear thinning behaviour. In vivo preclinical efficacy of the optimized gel formulation revealed improved skin structure in comparison with negative control group. The histopathological examination of mice skin treated with optimized gel formulation resulted in decreased epidermal hyperplasia and intactness of outer keratinized epidermal layer with the inner layer. The outcomes of the apremilast-loaded liquid crystalline nanoparticulate gel demonstrated anti-atopic dermatitis potential.

Utilization of Lyotropic Liquid Crystalline Gels for Chronic Wound Management.

Management of chronic wounds is becoming a serious health problem worldwide. To treat chronic wounds, a suitable healing environment and sustained delivery of growth factors must be guaranteed. Different therapies have been applied for the treatment of chronic wounds such as debridement and photodynamic therapy. Among them, growth factors are widely used therapeutic drugs. However, at present, growth factor delivery systems cannot meet the demand of clinical practice; therefore new methods should be developed to meet the emerging need. For this reason, researchers have tried to modify hydrogels through some methods such as chemical synthesis and molecule modifications to enhance their properties. However, there are still a large number of limitations in practical use like byproduct problems, difficulty to industrialize, and instability of growth factor. Moreover, applications of new materials like lyotropic liquid crystalline (LLC) on chronic wounds have emerged as a new trend. The structure of LLC is endowed with many excellent properties including low cost, ordered structure, and excellent loading efficiency. LLC can provide a moist local environment for the wound, and its lattice structure can embed the growth factors in the water channel. Growth factor is released from the high-concentration carrier to the low-concentration release medium, which can be precisely regulated. Therefore, it can provide sustained and stable delivery of growth factors as well as a suitable healing environment for wounds, which is a promising candidate for chronic wound healing and has a broad prospective application. In conclusion, more reliable and applicable drug delivery systems should be designed and tested to improve the therapy and management of chronic wounds.

A Mechanistic Study on the Fluidization and Enhancement Effects of Cineole Toward Stratum Corneum Intercellular Lamellar Lipids: A Liquid Crystalline Model Approach.

The stratum corneum (SC) serves as the primary barrier for permeation in human skin. Penetration enhancers, such as 1,8-cineole, are utilized to enhance the permeation of drugs. Cineole increases the permeation of chemicals through different mechanisms. However, its mechanism, particularly at high concentrations, has not been well-studied and is the subject of the present investigation. In continuation of our previous studies, the present investigation aims to elucidate the mechanism of action and concentration dependency of the effects of 1,8-cineole on the structure, diffusional properties, and partitioning behavior of the SC at high concentrations. This will be achieved through lamellar liquid crystalline models and ex-vivo skin studies. A lamellar liquid crystalline lipid matrix model in the presence (25 - 90%, w/w) and absence of cineole was prepared from SC lipids and characterized by X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and polarized light microscopy (PLM) studies. Release of the model lipophilic drug (diazepam) from cineole and cineole-treated matrices and the permeation of the drug from cineole and cineole-containing matrices (as a vehicle similar to the stratum corneum lipids) through excised rat skin were studied. Drug assay was performed by HPLC. The PLM, DSC, and X-ray studies showed that the model matrix had a lamellar gel-liquid crystalline structure, and cineole fluidized the structure concentration-dependently and created other mesomorphic textures, such as myelinic figures. Release experiments showed that diffusion coefficients remained almost constant at high cineole concentrations of 40-90%, suggesting similar fluidization states. Skin permeation studies indicated that the diffusion coefficient (estimated from lag-time) increased concentration-dependently and played a role in permeability coefficient (Kp) increments alongside the increased partitioning of the model drug into the skin. Data suggest that high concentrations of cineole at the skin surface might not provide enough cineole in the skin for full fluidization, despite the similarity of the vehicle to SC lipids and even at high concentrations. The enhancement effect of cineole is concentration-dependent and might reach maximum fluidization at certain concentrations, but this maximum might not be easily achievable when cineole is used in formulations as pure or in a vehicle.

A Mechanistic Study on the Fluidization and Enhancement Effects of Cineole Toward Stratum Corneum Intercellular Lamellar Lipids: A Liquid Crystalline Model Approach

Background: The stratum corneum (SC) serves as the primary barrier for permeation in human skin. Penetration enhancers, such as 1,8-cineole, are utilized to enhance the permeation of drugs. Cineole increases the permeation of chemicals through different mechanisms. However, its mechanism, particularly at high concentrations, has not been well-studied and is the subject of the present investigation. Objectives: In continuation of our previous studies, the present investigation aims to elucidate the mechanism of action and concentration dependency of the effects of 1,8-cineole on the structure, diffusional properties, and partitioning behavior of the SC at high concentrations. This will be achieved through lamellar liquid crystalline models and ex-vivo skin studies. Methods: A lamellar liquid crystalline lipid matrix model in the presence (25 - 90%, w/w) and absence of cineole was prepared from SC lipids and characterized by X-ray diffraction, differential scanning calorimetry (DSC), Thermogravimetric Analysis (TGA), and Polarized Light Microscopy (PLM) studies. The release of the model lipophilic drug (diazepam) from cineole and cineole-treated matrices and the permeation of the drug from cineole and cineole-containing matrices (as a vehicle similar to the stratum corneum lipids) through excised rat skin were studied. A drug assay was performed by HPLC. Results: The PLM, DSC, and X-ray studies showed that the model matrix had a lamellar gel-liquid crystalline structure, and cineole fluidized the structure concentration dependently and created other mesomorphic textures, such as myelinic figures. Release experiments showed that diffusion coefficients remained almost constant at high cineole concentrations of 40-90%, suggesting similar fluidization states. Skin permeation studies indicated that the diffusion coefficient (estimated from lag-time) increased concentration-dependently and played a role in permeability coefficient (Kp) increments alongside the increased partitioning of the model drug into the skin. Data suggest that high concentrations of cineole at the skin surface might not provide enough cineole in the skin for full fluidization, despite the similarity of the vehicle to SC lipids and even at high concentrations. Conclusions: The enhancement effect of cineole is concentration-dependent and might reach maximum fluidization at certain concentrations, but this maximum might not be easily achievable when cineole is used in formulations as pure or in a vehicle.

Two-Color Cholesteric Liquid Crystalline Gels for Reversible Writing and Erasing Information Encryption.

Bright structural color derived from the unique helical superstructure of cholesteric liquid crystals (CLCs) has attracted much attention. In addition, fluorescence color is an intrinsic emission upon excitation, which can be observed often under UV light. However, it is a challenge to combine the fluorescence and structural colors to construct a self-supporting system at the same time. In this work, a photoresponsive cyanostilbene-based gelator (CSpy-C10) is synthesized, which emits blue fluorescence in LC. CSpy-C10 can gel LCs and further construct thermo-/photoresponsive CLC physical gels. The structural color of the CLCs, fluorescence, and mechanical properties of the gels can be independently regulated due to the separation of the chiral unit and photoresponsive unit with aggregation-induced emission behavior. Finally, the reversible information encryption including writing and erasing based on the changes in fluorescence are explored. This kind of two-color material can be applied in the fields ranging from information encryption, fluorescent display to high-tech anticounterfeiting.

Industry update, December 2022.

Industry update, December 2022.

Balancing Compatibility and Gelability for High-Performance Cholesteric Liquid Crystalline Physical Gels

Liquid crystalline physical gels (LCPGs) have attracted increasing interest because of their mechanical properties and stimulus-response behaviors. However, due to their gelator properties such as thermal stability, gelation capability, and compatibility in liquid crystals, development of LCPGs with high performances still remains a huge challenging task. Herein, four novel gelators ((l)-PH, (d)-PH, (l)-P2H, and (d)-P2H) based on 1,4-benzenedicarboxamide phenylalanine derivatives containing one or two ethylene glycol groups have been designed and synthesized. It is found that the ethylene glycol group plays a significant role in improving the compatibility between the gelator and the liquid crystal. All of the prepared compounds can form stable LCPGs in P0616A. In particular, the storage modulus of LCPG with 9.0 wt % of (l)-PH with one ethylene glycol unit is higher than 106 Pa, which is similar to SmC gels and advantageous over previously reported nematic LCPGs. Furthermore, the prepared gels display a strong Cotton effect with hand-preferred twisted fiber networks and the self-assembled aggregates of (l)-PH can induce P0616A to form a cholesteric fingerprint structure. Thus, these low molecular weight gelators provide a strategy to construct high-performance cholesteric LCPGs for the realization of LC device applications.

Formulation and In-vitro, In-vivo Evaluation of Itraconazole and Itraconazole Co-Crystals Loaded Glyceryl Monooleate Based Liquid Crystalline Gel

The objectives of present investigation were to prepare and evaluate liquid crystalline gel, study the effect of water concentration on liquid crystalline phases, incorporate antifungal agent and itraconazole (ITZ) co-crystals into liquid crystalline vehicle. Liquid crystalline gel formulations were prepared by using glyceryl mono-oleate GMO, water and other excipients. The prepared gel formulations were evaluated for various parameters like rheological, in vitro drug diffusion and in vivo skin irritation test etc. Differential scanning calorimetric spectra of ITZ loaded gel showed higher transition peak temperature 96.71oC and ITZ loaded co-crystal gel showed 99.2oC and pH 6.8 and 6.5 respectively. Enhanced rate of diffusion was observed when gels were loaded with co-crystals. The prepared liquid crystalline gel formulations containing itraconazole and its co-crystals were found useful in a topical delivery with improvement for in vitro and in vivo performance.

Hexagonal liquid crystalline system containing cinnamaldehyde for enhancement of skin permeation of sinomenine hydrochloride

Sinomenine hydrochloride (SH) is usually applied to treat rheumatoid arthritis (RA) with severe side effects due to oral administration. Cinnamaldehyde (CA) as essential oil possesses an anti-RA effect and can facilitate transdermal penetration. Hence, this study developed hexagonal liquid crystalline (HII) gels to deliver two components (SH and CA) across the skins. HII gels were prepared and characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS) and rheology. Moreover, in vitro drug release behavior and ex vivo skin permeation were investigated. Finally, Fourier transforms infrared spectral analysis (FTIR) and confocal laser scanning microscopy (CLSM) were used to explore the skin penetration mechanism. PLM and SAXS showed that the inner structure of the gels was HII phase. The addition of lipophilic or hydrophilic molecules slowed down one another’s release and the release model was dominated by Fickian diffusion (n < 0.43). Furthermore, in vitro permeation studies indicated that appropriate CA could improve the skin permeability of SH. FTIR and CLSM suggested that infiltration occurred due to disruption of the lipid bilayer structure and increased fluidity of the skin. In conclusion, HII gels and CA exhibited a penetration-promoting effect for transdermal applications in SH.

THE INFLUENCE OF CHLORPROMAZINE HYDROCHLORIDE ON THE THERMOTROPIC BEHAVIOR OF DIMYRISTOYL PHOSPHATIDYLCHOLINE LIPOSOMES AS REVEALED BY DIFFERENTIAL SCANNING CALORIMETRY

Objective: The aim of this study is to investigate the influence of the model cationic, amphiphilic, drug chlorpromazine hydrochloride (CPZ-HCl) on the thermotropic behavior of dimyristoyl phosphatidylcholine (DMPC) liposomes, using differential scanning calorimetry (DSC). The effect of sonication, charged lipids and CPZ-HCl at concentrations known to cause anesthesia on the enthalpy (ΔHt), entropy (ΔSt), phase transition (Tc), pre-transition (pre-TC) and half-height width (HHW) of DSC thermograms were examined. Methods: The experiments conducted, using the Perkin Elmer (DSC-2C), include the effect of a wide range of CPZ-HCl concentrations on ΔHt, ΔSt, Tc, pre-Tc and HHW of DSC thermograms of DMPC liposomes. The effect of sonication on ΔHt, ΔSt, Tc and HHW of DSC thermograms of DMPC/CPZ-HCl liposomes as a function of sonication time. The effect of both positively charged stearyl amine (ST) and negatively charged diacetyl phosphate (DCP) lipids on ΔHt, ΔSt and Tc of DMPC/CPZ-HCl liposomes. In addition, the effect of CPZ-HCl at concentrations known to cause anesthesia on ΔHt, ΔSt. and Tc of DMPC liposomes in the presence and absence of ST and DCP in phosphate buffer (pH 7.4), was also carried out. Results: Using DSC, CPZ-HCl concentrations as low as 1×10-7M were observed to alter the gel-liquid crystalline phase transition and thus to possess a membrane destabilizing effect. CPZ-HCl reduces ΔHt, ΔSt, TC, the pre-TC and increases HHW of DMPC liposomes. ΔHt and ΔSt of DMPC liposomes were observed to decrease with increasing CPZ-HCl concentrations, exhibiting an inflection point at 5×10-5M. ΔHt of DMPC liposomes was observed to decrease linearly in the absence and presence of and CPZ-HCl as a function of sonication time. Both ΔHt and ΔSt of DMPC liposomes were observed to increase in the presence of cationic lipid (ST) and to decrease in the presence of anionic lipid (DCP). ΔSt and Tc of DMPC, DMPC/ST, DMPC/DCP liposomes, were found to decrease as a function of CPZ-HCl concentrations known to cause anesthesia. Conclusion: Using DSC, CPZ-HCl concentrations, as low as 1×10-7 M were observed to influence the enthalpy, entropy, phase transition, pre-transition and half-height width of DSC thermograms of DMPC liposomes, altering the gel-liquid crystalline phase transition and thus possessing a membrane destabilizing effect. It can also be inferred that CPZ-HCl interacts with both the polar head group and the hydrophobic interior of the phospholipid bilayer. These results could support the hypothesis that the addition of local anesthetics might trigger a change in the lipid surrounding the sodium channel from the gel to the liquid crystalline state, allowing the sodium channel to close with the resulting anesthesia.

Advances in the Supramolecular Chemistry of Tetracoordinate Boron-Containing Organic Molecules into Organogels and Mesogens.

Boron-containing organic compounds are well accepted as a class of compounds having excellent photophysical properties. In addition to the unique photophysical properties, the ease of synthesis and structural robustness make tetracoordinate boron complexes ideal for a variety of applications. While significant light has been thrown on their luminescence properties, there is no collective attention to their supramolecular chemistry. In this mini review, we discuss the progress made in the supramolecular chemistry of these compounds which includes their utility as building blocks for liquid crystalline materials and gels largely driven by various non-covalent interactions like H-bonding, CH-π interactions, BF-π interactions and Van der Waals forces. The organoboron compounds presented here are prepared from easy-to-synthesize chelating units such as imines, diiminates, ketoiminates and diketonates. Moreover, the presence of heteroatoms such as nitrogen, oxygen and sulfur, and the presence of aromatic rings facilitate non-covalent interactions which not only favor their formation but also helps to stabilize the self-assembled structures.

Role of Water in the Lyotropic Liquid Crystalline Lithium Iodide-Iodine-Water-C12E10 Mesophase as a Gel Electrolyte in a Dye-Sensitized Solar Cell.

By replacing volatile and flammable organic-based electrolytes with gel electrolytes, dye-sensitized solar cells (DSSCs) may be a viable and more practical alternative to other clean energy sources. Although they present a promising alternative, gel electrolytes still have some drawbacks for practical applications, such as low ionic conductivity and infusion difficulties into the pores of the working electrode. Here, we introduce a new one-step fabrication method that uses a lyotropic liquid crystalline (LLC) gel electrolyte (LiI:I2:H2O:C12H25(OCH2CH2)10OH) and a dye (N719) to construct a DSSC that performs (7.32%) 2.2 times better compared with a traditional two-step production. Water plays a key role in the gel electrolyte, where the H2O/LiI mole ratio is around 2.57 under ambient laboratory conditions (ALCs); however, this ratio linearly increases to 4.00 and then to 5.85 at 40 and 75% humidities, respectively, without affecting the two-dimensional (2D) hexagonal structure of the mesophase. The ionic conductivity of the gel electrolyte linearly increases accordingly, by 2.2 (4.8 × 10-5 to 10.6 × 10-5) and 13.1 times (63.0 × 10-5 S/cm) from ALC to 40 and ALC to 75% humidity, respectively. Increasing water in the gel phase improves the conductivity of the LLC mesophase and the short-circuit current (Isc) of the DSSC, but negatively influences the open-circuit voltage (Voc) of the cell, equilibrium reaction between the LiI and I2, and the anchoring of the dye molecules over the titania surface.

Chlorosulfolipid (Danicalipin A) Membrane Structure: Hybrid Molecular Dynamics Simulation Studies.

Chlorosulfolipids (CSLs) are major components of flagellar membranes in sea algae. Unlike typical biological lipids, CSLs contain hydrophilic sulfate and chloride groups in the hydrocarbon tail; this has deterred the prediction of the CSL membrane structure since 1960. In this study, we combine coarse-grained (CG) and atomistic molecular dynamics (MD) simulations to gain significant insights into the membrane structure of Danicalipin A, which is one of the typical CSLs. It is observed from the CG MD that Danicalipin A lipids form a stable monolayer membrane structure wherein the hydrocarbon moieties are sandwiched by hydrophilic sulfate and chloride groups in both the head and tail regions. On the basis of the mesoscopic structure, we built the corresponding atomistic model to investigate the integrity of the CSL monolayer membrane structure. The monolayer membrane comprising bent lipids shows high thermal stability up to 313 K. The gel-liquid crystalline phase transition is observed around 300 K.

A luminescent lyotropic liquid-crystalline gel of a water-soluble Ir(III) complex

In the present study, the synthesis and properties of a novel water soluble Ir(III) complex of formula [(ppy)2Ir(dpq)]CH3CO2 is described, where ppy is the cyclometalated 2-phenylpyridine ligand and dpq the dipyrido[3,2-f:2′,3′-h]quinoxaline used as ancillary ligand. Own to its specific molecular structure, this complex forms highly ordered supramolecular gels in water on a wide range of concentration, from 3 to 14% w/w. The gel phase shows birefringence under cross polarisers that is completely loss when water is removed, evidence of the formation of a true lyotropic liquid-crystalline gel, without the need of an additional gelator. The gel is macroscopically formed of entangled microfibers that can be seen under optical microscope and that display luminescent properties as observed by confocal microscopy. X-Ray diffraction allowed to resolve the structure of the lyotropic mesophase that is formed by columns of complex cations organised in a tetrahedral manner which are in turn arranged in a larger oblique lattice, hence showing a high degree of order. The photophysical properties of the complex in its different state of matter (solid, gel phase and xerogel) are presented and discussed.

Stabilization of vitamin C in emulsions of liquid crystalline structures

Emulsified systems are widely used for topical delivery with the aim of optimizing cutaneous absorption and offering a pleasant sensory. They also may provide a protection of the active molecule against oxidation and/or degradation. The oil phase of o/w emulsions may consist of liquid crystalline structures, especially lamellar structures which are similar to those found in the stratum corneum lipids. In the present work, o/w emulsions containing liquid crystals of mixed cetyl alcohol and Polysorbate 60 were developed for topical delivery of vitamin C, a potent antioxidant with several applications in the cosmetic and pharmaceutical fields. In addition to the well-documented lipid supplementation of the stratum corneum, the liquid crystal emulsions provide a significant chemical stabilization of vitamin C against its degradation. Emulsions were characterized by X-ray diffraction, polarized optical microscopy, and transmission electron microscopy. The stability of vitamin C in the formulations was evaluated upon storage in different conditions of temperature. The emulsions contain a complex colloidal structure, consisting of lamellar liquid crystalline (Lα) and crystalline lamellar gel (Lβ) phases, that provide a very efficient protection of vitamin C against its degradation.

Chemical Oscillation and Morphological Oscillation in Catalyst-Embedded Lyotropic Liquid Crystalline Gels.

Liquid crystalline gels offer promising means in generating smart materials due to programmable mechanics and reversible shape changes in response to external stimuli. We demonstrate a simple and convenient method of constructing catalyst-embedded lyotropic liquid crystalline (LLC) gels and achieve chemomechanical oscillator by converting chemical waves in Belousov–Zhabotinsky (BZ) reaction. We observe the directed chemical oscillations on LLC sticks accompanied by small-scale oscillatory swellings–shrinkages that are synchronized with the chemical waves of an LLC stick. To amplify the mechanical oscillations, we further fabricate small LLC fibers and achieve macroscopically oscillatory bending–unbending transition of the LLC fiber driven by a BZ reaction.

Gelation, Liquid Crystalline Behavior, and Ionic Conductivity of Nanocomposite Ionogel Electrolytes Based On Attapulgite Nanorods.

Anisotropic nanoparticles and their dispersions have attracted much attention because of their distinguished characteristics and promising applications. In this study, the novel liquid crystalline nanocomposite ionogel electrolyte materials based on anisotropic nanoparticles of attapulgite (ATP) have been prepared. The gelation, liquid crystalline (LC) behavior, thermal stability, and ionic conductivity were systematically investigated. Rheological, polarized optical microscopy (POM), and small-angle X-ray scattering (SAXS) measurements demonstrated that these liquid crystalline ionogels showed a two-step mechanism consisting of gelation and subsequent reorganization of the gel. Interestingly, the obtained ionogel electrolytes were very stable and LC gel structures were not destroyed even though the temperature was as high as 200 °C. Furthermore, these ionogels possessed outstanding thermal stability and the decomposition temperature exceeded 400 °C. Remarkably, the LC nanocomposite ionogel electrolytes exhibited high room temperature ionic conductivity and the value still exceeded 1.0 × 10-3 S/cm even when the ATP concentration up to 30 wt %. These novel findings are very useful for the fabrication of high temperature resistant electrochemical devices and liquid crystalline nanocomposite materials.