Cosmosil Cholester-HPLC法分离番茄红素异构体的研究

番茄红素是一种由11个共轭双键和2个非共轭双键组成的直链型多不饱和烯烃。由于分子中双键数目较多,番茄红素有很多空间异构体。对COSMOSIL Cholester-HPLC法分离番茄红素异构体的方法进行了研究并优化了分离条件。最终确定的试验条件如下:流动相为V(四氢呋喃)∶V(乙腈)=10∶90,进样量20μL,流速1 mL/min,检测波长472 nm。此试验条件下进行的重复性试验表明,该方法分离效果比较理想,重复性良好。

Novel Biomaterial for NCT - “Rigid” Particles of (DNA-gadolinium) Liquid-Crystalline Dispersions

The formation and physico-chemical properties of biomaterial, based on double-stranded (ds) DNA molecules and bearing high concentration of gadolinium, is described. This “rigid” biomaterial demonstrate a few unique properties: (i) the ds DNA molecules forming complexes with gadolinium are fixed in the spatial structure of “rigid” particles, (ii) an abnormal negative band in the circular dichroism spectrum permits to follow the formation of this biomaterial;(iii) local concentration gadolinium in the content of biomaterial can reach 40%. These properties show that we are dealing with a novel type of biomaterial strongly enriched by gadolinium. This opens a gateway for practical application of this biomaterial for neutron-capture reactions. A first attempt to apply this material for neutron-capture reaction in combination with neutron generator of thermal neutron flux was performed. Positive result obtained at destruction of CHO cells allows one to state that the advantages of this biomaterial are a simple manipulation with it, a possibility to adjust its gadolinium content, long-term stability of its physico-chemical properties, as well as a reduced cost of neutron-capture experiment.

PREPARATION AND PROPERTIES OF ETHYL-CYANOETHYL CELLULOSE/POLYACRYLIC ACID COMPOSITE FILMS WITH REFLECTION COLORS

Ethyl-cyanoethyl cellulose [(E-CE)C]/acrylic acid (AA) becomes a cholesteric liquid crystalline solution withvivid colors when the (E-CE)C concentration is 42 wt%～52 wt%. (E-CE)C/polyacrylic acid (PAA) composites withcholesteric structure were prepared by polymerzing AA in (E-CE)C/AA liquid crystalline solutions. The layers of orderedpolymer chains in the cholesteric phase were inclined during polymerization and the degree of the inclination depended onthe polymerization temperature and the concentration of the solution before polymerization. The cholesteric structure in thecomposites could not be changed when temperature was lower than 100℃. Cross-linking of the PAA in compositesimproved their water-resistance. The cholesteric order of the composites without cross-linking was destroyed when theywhere immersed in water. The color derived from the selective reflection of the cholesteric phase of the cross-linkedcomposites turned from blue to red after the composites absorbed water. The color of the composites could be returned to theoriginal one when the absorbed water was removed from the swollen composites.

Electro-optical properties cholesteric liquid of polymer stabilized crystal film＊

Liquid crystals （LCs） and polymers are extensively used in various electro-optical applications. In this paper, normal mode polymer stabilized cholesteric LC film is prepared and studied. The effects of chiral dopant and monomer concentrations on the electro-optical properties, such as contrast ratio, driving voltage, hysteresis width and response time, are investigated. The reasons of electro-optical properties influenced by the concentrations of the materials are discussed. Through the proper material recipe, the electro-optical properties of polymer stabilized cholesteric LC film can be optimized.

BAND-LIKE TEXTURE OF ETHYLCYANOETHYL CELLULOSE MESOPHASE

In the ethyl-cyanoethylcellulose ((E-CE)C)/dichloroacetic acid (DCA) cholesteric liquid crystalline solution, the hand-like texture is formed when the mesophase aggregates with the disk-like texture grow to big enough and merge with each other with increasing concentration. The band-like texture is composed of parallel equidistant bright and dark alternative strips which are about 0.2-2.0 μm in width. In the band-like texture, the layers of ordered polymer chains are perpendicular to the solution film and the axes of helicoids are parallel to it. The width of the strips is different in different zones. Under the effect of an external magnetic field, the strips in the band-like texture first become wider and then narrower gradually.Moreover, the axes of helicoids in the (E-CE) C/DCA mesomorphic solution change from the direction normal to the magnetic field to the agreement with the magnetic field direction.

Fixation for the helical structure of a glassy cholesteric liquid crystal reflective film

The planar texture of glassy cholesteric siloxane cyclic side-chain liquid crystals was fixed by quenching initially. Then the polymer network formed by the optically active polymerizable monomers imposed additional constraints on the motion of chain segments of the glassy liquid crystal and then further stabilized the molecule arrangement. A cholesteric liquid crystal film with stable optical properties was developed by this method.

Research progress of cholesteric liquid crystals with broadband reflection characteristics in application of intelligent optical modulation materials

Cholesteric liquid crystals（CLCs） have recently sparked an enormous amount of interest in the development of soft matter materials due to their unique ability to self-organize into a helical supra-molecular architecture and their excellent selective reflection of light based on the Bragg relationship.Nowadays,by the virtue of building the self-organized nanostructures with pitch gradient or non-uniform pitch distribution,extensive work has already been performed to obtain CLC films with a broad reflection band.Based on authors＇ many years＇ research experience,this critical review systematically summarizes the physical and optical background of the CLCs with broadband reflection characteristics,methods to obtain broadband reflection of CLCs,as well as the application in the field of intelligent optical modulation materials.Combined with the research status and the advantages in the field,the important basic and applied scientific problems in the research direction are also introduced.

Quantitative Analysis of Elements in Gallstones and Biles from Chinese and Japanese Patients

The concentration of 26 elements in biles and gallstones from Chi-nese patients and the concentration of 10 elements from Japanese patients withgallstones were determined by inductively coupled plasma atomic emission spec-trometry (ICAP). Comparison of the level of elements between cholesterol andpigment gallstones revealed that Ca, Na, Fe, Cu, S, and Zn were higher inpigment gallstones than those in the cholesterol gallstones. Cholesterol stones aredivided into three subtypes: pure, mixed and combinated cholesterol stone.There were no significant difference among element contents. The levels of Ca,P, S, Li, and Ba in gallbladder biles were obviously higher in control groupthan in gallstone group. The element composition in gallbladder bile were similarto those in common bile duct bile. The former were 2～3 time high than the lat-ter.

CHOLESTERIC LIQUID CRYSTALLINE CHARACTER ON THE SURFACE OF CHITOSAN/POLYACRYLIC ACID COMPOSITES

The cholesteric liquid crystalline structure in chitosan/polyacrylic acid composite films was studied by surface techniques. A periodical lamellar-like structure was observed in the permanganic acid etched film surface by both scanning electron microscopy (SEM) and atomic force microscopy (AFM), instead of the thumb-print texture which can be detected with polarized optical microscopy. It is suggested that the periodical lamellar-like structure is induced by the etching selectivity between cholesteric layers due to different molecular arrangement on the film surface. Four kinds of perpendicular disclinations, i.e. chi --> tau (-) + lambda (+), chi --> lambda (-) + tau (+), chi --> tau (-) + tau (+) and chi --> lambda (-) + lambda (+) were found in the composite films from SEM observations. The smallest periodicity of lamellar-like structure (equals to half pitch) is 20 similar to 40 nm measured with AFM.

KINETICSOF TRANSITION FROM ISOTROPIC TO CHOLESTERIC PHASE FOR A THERMOTROPIC CELLULOSE DERIVATIVE

The kinetics of mesophase formation of a thermotropic hydroxyethyl cellulose acetate from isotropic phase to cholesteric mesophase has been studied by means of depolarizing transmittance method. Avrami type analysis of the data gives an exponent n close to 1, which suggests the nucleation followed by rod-like growth. It means that the kinetic behavior of phase transition from isotropic to cholesteric mesophase is very similar to that of the mesophase formation from isotropic to nematic mesophase.

Reinvestigation of liquid crystalline property of dimesogenic compound consisting of cholesterol and cyanobiphenyl

The dimesogenic compound consisting of cholesterol and cyanobiphenyl mesogens interlinked by ω-oxyalkanoyl spacer was synthesized. The mesomorphic properties were investigated by differential scanning calorimetry （DSC）, polarizing optical microscopy （POM）, and X-ray diffraction （XRD）. The experimental results indicated that this compound exhibited mesophase over a much wider temperature range and a new mesophase blue phase （BP）. Focal conic domains （FCDs） and droplets texture to the smectic A phase （SA）, oily streaks typical to the chiral nematic （N＊） phase were found in the liquid crystalline state, respectively. Besides, it exhibited a smectic layer spacing about 1.0 time to the length of the molecule, which indicated a monolayer type of SA ordering. 2009 Hal Quan Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Synthesis and Characterization of a Novel Liquid Crystalline Chitin Quaternary Ammonium Chitosan Salt

N -Butyl chitosan(NBCS) derivatives were prepared by introducing butyl groups into the amine groups of chitosan via Schiff base intermediates. The quaternization of NBCS was carried out by using ethyl iodide to produce water-soluble cationic polyelectrolytes. The degree of the substitution of the products was measured by means of the electron spectroscopy for a successful chemical analysis. The quaternary ammonium chitosan salt(QACS) was proved to be a novel cholesteric liquid crystalline chitin, by means of the polarized optical microscopy and the circular dichroism spectropolarimetry. The critical mass fraction of the QACS/formic acid solution forming a lyotropic liquid crystal phase was 50%, which was almost the same as that of the NBCS/formic acid solution, but much higher than that of the chitosan in the same solvent.

SYNTHESIS OF AZA-CROWN-ETHER CHOLESTERIC LIQUID CRYSTALS

Five aza-crown-ethers were synthesized and four of them shown to have cholesteric liquid crystalline properties. Their properties relevant to cholesteric liquid crystal were determined by DSC and the textures. The type of cholesteric mesomorphic azacrown ether have not been reported so far.

Tunable Optical Filters Based on Different Configurations with Cholesteric Liquid Crystals

Optical filters with different configurations based on cholesteric liquid crystals （CLCs） are designed. The central wavelength from CLCs can be tuned by the electric field or temperature. For the electric field tuning, the ITO is designed with circular patterns, which can make the tunable range 18 nm. For the temperature tuning, two-layer- CLC configurations are used. The experimental results indicate that a deepened or broadened bandgap from the CLC can be achieved by different handedness or concentrations of chiral dopants. The spectrum study is carried out.

Thermo-Chromic Response of Polymer Stabilized Cholesteric Liquid Crystal for Thermal Imaging

Cholesteric liquid crystal(Ch-LC)exhibits many remarkable optical properties due to formation of a macroscopic helical structure.A low amount of monomer(5wt.%)is dispersed into cholesteric liquid crystal and get polymerized under UV radiations to form polymer stabilized cholesteric texture(PSCT).The thermo-chromic response made this device suitable for the developing applications in thermal imaging.Temperature based measurements of PSCT exploits the key property of some polymer stabilized cholesteric liquid crystals(PSCLC)to reflect definite colors at specific temperatures.The selective color of PSCT texture shifts with raise in temperature from 30oC to 85oC,which can be utilized in thermal imaging applications.

Effect of Ferroelectric Nanopowder on Electrical and Acoustical Properties of Cholesteric Liquid Crystal

The composite materials based on nanopowder dispersed liquid crystals are important both from fundamental research and device applications due to their unique properties such as improvement in various properties like electrical,optical,thermal,energy storage and spontaneous polarization etc.The proper selection of nanoparticle and its size which to be dispersed in particular liquid crystals is very important for a particular application.In the present study,a ferroelectric nanopowder of Barium Titanate(BaTiO3)was dispersed in cholesteric liquid crystal and the same was confirmed by Fourier Transform Infrared(FTIR)Spectroscopy.The various acoustical properties like ultrasonic velocity,density,Adiabatic Compressibility,Rao Constant,Wada Constant and Acoustic Impedance were investigated by ultrasonic interferometer at room temperature at fixed frequency.The dielectric constant was determined by Precision Impedance Analyzer.In addition to these investigations,particle size and surface area were also measured.Our investigation shows enhanced in dielectric and acoustical properties which may be useful for device applications extensively in microelectronics,low cost-photovoltaic devices,and custom-shaped containers possibly applied as a coating.

Synthesis and Characterization of Cholesteric Thermotropic Liquid Crystalline Polyesters Based on Isosorbide

BACKGROUND: Generally main chain cholesteric thermotropic liquid crystalline polymers are prepared form chiral diacid or diol monomer. But these monomers are costly. Isosorbide is chiral cycloaliphatic diol accessible from renewable resources in the form of pure enantiomers. Thus it is used to synthesize main chain cholesteric thermotropic liquid crystalline polymers. Incorporation of phenyl hydroquinone into the backbone of the main chain frustrates chain packing, thus lowering the crystallinity and depressing the melting point below the degradation temperature, also improves the solubility due to disruption of packing and maintains the mechanical and thermal performance. RESULTS: Optical microscopy study reveals that more than 50% of isosorbide content with phenyl hydroquinone and terephthalic acid showed “yellow iridescent oily streaks” with a background of mosaic/marble texture. These are the typical textures of cholesteric liquid crystalline phase. Copolyesters based on phenyl hydroquinone, isosorbide and terephthalic acid are soluble in aprotic solvents like N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP). Solubility increases with the content of isosorbide percent. Thermal stability of all copolyesters was more than 300?C on the basis of 10% wt loss. CONCLUSIONS: It was found that main chain cholesteric thermotropic liquid crystalline polymers can be prepared form chiral cycloaliphatic diol such as isosorbide. Main chain cholesteric thermotropic liquid crystalline polyesters are prepared from phenyl hydroquinone, isosorbide and terephthalic acid showed thermal stability more than 300?C. Main chain cholesteric thermotropic liquid crystalline polymers are soluble in aprotic solvents like DMAC, DMSO, DMF and NMP.

Controllable CPL response driven by achiral UV-photosensitive dichroic dye through cholesteric liquid crystals

Versatile stimuli-responsive circularly polarized luminescent(CPL)materials have potential applications in information storage,security encryption,and intelligent displays.In this study,the Z/E isomerization of ultraviolet(UV)-photosensitive achiralα-cyanostilbene derivative was used as an achiral dichroic dye(Switch)to drive the controllable CPL-active response in cholesteric liquid crystals(CLCs).Under irradiation by 365 nm UV light,the resulting CLCs-Z-Switch underwent a Z-to-E configuration isomerization as CLCs-E-Switch,accompanied by a decrease in its dichroic order parameter(SFvalue)from 0.15to 0.07.Although the quantum yield(QY)of CLCs-E-Switch increased from 8.1%(CLCs-Z-Switch)to 16.8%,the corresponding glumvalues of CPL emission decreased from+0.55/-0.57 to+0.37/-0.39 due to a decrease in the order of helical arrangement of E-Switch in E7 media.This study enables photosensitive CLCs-Switch to be applied for optical information storage devices.

Dynamic Control of Multiple Optical Patterns of Cholesteric Liquid Crystal Microdroplets by Light-Driven Molecular Motors

The key to high-level encryption and anti-counterfeiting techniques is the storage of multiple levels of distinct information that can be individually and precisely addressed by certain stimuli.This continues to be a formidable challenge as the concealed images or codes must be read with fast response and high resolution without cross-talk to the first layer of information.Here,we report a non-fluorescencebased strategy to establish responsive encryption labels taking advantage of solely tuning multiple optical patterns of cholesteric liquid crystal(CLC)microdroplets doped with light-driven molecular motors.The photo-triggered unidirectional rotation of the motor induced not only changes in the helical twist power value but the opposite helical orientation of the superstructure in CLCs as well,resulting in changes in both the structural color and the selective reflection of circularly polar light.The designed labels,which featured highly selective addressability of dual-level distinct information,good reversibility,and viewing angle-independence,were applied to build devices for daily practical use,demonstrating great potential in anti-counterfeiting technology and provide a versatile platform for enhanced data protection and encryption of authentic information.

Multi-functional stimuli-responsive biomimetic flower assembled from CLCE and MOF-based pedals

Simulating the structures and behaviors of living organisms are of great significance to develop novel multi-functional intelligent devices. However, the development of biomimetic devices with complex deformable structures and synergistic properties is still on the way. Herein, we propose a simple and effective approach to create the multi-functional stimuli-responsive biomimetic devices with independently pre-programmable colorful visual patterns, complex geometries and morphable modes. The metal organic framework(MOF)-based composite film acts as a rigidity actuation substrate to support and mechanically guide the spatial configuration of the soft chiral nematic liquid crystal elastomer(CLCE) sheet. We can directly program the structural color of the CLCE sheet by adjusting the thickness distribution without tedious chemical modification. By using this coordination strategy, we fabricate an artificial flower, which exhibits a synergistic effect of both shape transformation and color change like paeonia ‘Coral Sunset’at different flowering stages, and can even perform different flowering behaviors by bending, twisting and curling petals. The assembled bionic flower is innovatively demonstrated to respond to local stimuli of humidity, heat or ultraviolet irradiation. Therefore, the spatial assembly of CLCE combined with functional MOF materials has a wide range of potential application in multi-functional integrated artificial systems.