The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/watersystems has been investigated, and the liquid crystal area has been identified, which covers abouttwo thirds of the whole phase diagram. The ...The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/watersystems has been investigated, and the liquid crystal area has been identified, which covers abouttwo thirds of the whole phase diagram. The liquid crystal structure and behavior have been alsostudied by using polarizing texture, small angle X-ray scattering, ~2H-NMR and rheometer etc. Theresult shows that when the composition of the system changes along the line of AA′ in this largeliquid crystal region, the structural change iscubic→cubic/lamellar→lamellar→larnellar/hexagonal→hexagonal. Meanwhile, we made the firstattempt of systematic study of the rheological properties of the above system. The lattice constantsof cubic and hexagonal liquid crystals are 10.53 and 5.68 nm, respectively.展开更多
Lyotropic liquid crystals have lubricating properties due to their ordered assembly and fluidity,whose mesogens are often characterized by amphiphilic properties.Despite the attention that graphene oxide(GO)has been s...Lyotropic liquid crystals have lubricating properties due to their ordered assembly and fluidity,whose mesogens are often characterized by amphiphilic properties.Despite the attention that graphene oxide(GO)has been studied as a novel amphiphilic lyotropic mesogen this decade,and GO applied as a lubrication additive has been demonstrated in both oil and water-based systems,little research reveals the interfacial lubrication of GO liquid crystals yet.This work reports that GO aqueous dispersion can form lyotropic liquid crystals above a specific critical concentration of 5.00 mg/mL,providing a form of stable water-based lubricant,which can keep stable for several months and can reduce friction by 37.3%and wear by 25.24%.The liquid crystal phase was verified by polarizing microscope and synchrotron radiation small-angle X-ray scattering,and its rheological properties and viscoelasticity were studied by interfacial rheometer.The formation of lyotropic liquid crystals can enhance the stability of GO aqueous dispersions at high density,simultaneously ensuring friction decrease and anti-wear effect.It is attributed to the stable nematic network by the ordered GO sheets.The ordered assembly structure bears vertical shear force,therefore,reducing the wear.It is also assumed that the wide lateral size of graphene oxide promotes the nematic phase thus smoothes the graphene oxide film composed spontaneously under the coincidence of lamellar liquid crystal and 2D layered material.Through this work,the interlayer lubrication of GO was optimized,and the problem of GO dispersion sedimentation was solved by self-assembly.The range of interfacial lubrication of GO aqueous dispersion has been expanded and the synergistic effect is conducive to the environmentally friendly lubricants.展开更多
The organic lyotropic liquid crystal with long-range structural order is used as template to assemble inorganic/organic hybrid by doping pre-fabricated Ag nanoparticles. The lamellar hybrid with both hydrophilic and h...The organic lyotropic liquid crystal with long-range structural order is used as template to assemble inorganic/organic hybrid by doping pre-fabricated Ag nanoparticles. The lamellar hybrid with both hydrophilic and hydrophobic particles doped simultaneously is realized for the first time. The change of template structure after doping and the stability origin of dual-doped system are characterized by small angle X-ray scattering and polarized optical microscopy. Results show that the interaction and space matching between surfactant bilayers and doped particles are key factors to obtain stable hybrid.展开更多
The polymerization of amphiphilic self assemblies is a promising method to synthesize nano structured materials with novel properties. These materials have many attractive features for their application in biomedica...The polymerization of amphiphilic self assemblies is a promising method to synthesize nano structured materials with novel properties. These materials have many attractive features for their application in biomedical area and materials science, such as catalysis, separation, surface modification, and therapeutics areas. A general review on the polymerization of lipids and surfactant self assemblies to amphiphilic self assemblies is given in this paper with 49 references. The polymerization and the subsequently resulted structure of lipids in different morphologies are summarized. The polymerization of polymerizable surfactants(surfmers) in emulsion and liquid crystalline phases are also discussed. The potential application of new nano porous materials is briefly described.展开更多
Novel T-shaped bolaamphiphiles consisting of a bent 2,5-diphenylethynyl thiophene rigid core with two terminal glycerol units and a lateral n-alkyl chain have been synthesized via Kumuda and Sonogashira coupling react...Novel T-shaped bolaamphiphiles consisting of a bent 2,5-diphenylethynyl thiophene rigid core with two terminal glycerol units and a lateral n-alkyl chain have been synthesized via Kumuda and Sonogashira coupling reactions as key steps. Their liquid crystalline behavior was investigated by polarizing optical microscopy （POM）, differential scanning calorimetry （DSC）, and X-ray diffraction （XRD）. All such bolaamphiphiles can self-organize into square honeycomb LC phases with p4rnm symmetries in the presence of water, UV and PL measurements indicate fluorescent properties making them potential candidates for application in fluorescence sensor devices.展开更多
Lyotropic liquid crystals(LLCs)produced by the self-assembly of surfactant in water represent an important class of highly ordered soft materials that have a wide range of applications.This study investigates the LLCs...Lyotropic liquid crystals(LLCs)produced by the self-assembly of surfactant in water represent an important class of highly ordered soft materials that have a wide range of applications.This study investigates the LLCs formed by a zwitterionic surfactant(tetradecyldimethylaminoxide,C 14 DMAO)in water.The organization of C 14 DMAO within the LLCs was determined based on a detailed analysis of small-angle X-ray scattering measure-ments and polarized microscopy observations of a typical sample.Additional to the singe-phase region,which has a hexagonal organization,several two-phase regions were observed,exhibiting the coexistence of hexago-nal/cubic,cubic/lamellar,and hexagonal/lamellar phases.The phase behavior showed an obvious dependence on temperature,with more pronounced two-phase regions at lower temperatures.Using the LLCs as a matrix,Au nanospheres,nanoellipsoids,and nanorods were prepared without requiring additional reducing reagents.These three-and one-dimensional Au nanomaterials could be converted to two-dimensional plates via the introduc-tion of a small amount of cationic surfactant to the LLCs,such as cetyltrimethylammonium bromide(CTAB)and 1-hexadecyl-3-methylimidazolium bromide([C 16 MIm]B),which showed pronounced surface-enhanced Raman scattering activity towards solid rhodamine.The LLCs loaded with CTAB(or[C 16 MIm]B)and HAuCl 4 exhibited slightly different structures and mechanical strength from the original LLCs,thereby forming a new class of highly crowded colloidal materials.展开更多
The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which...The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which suggests the nucleation followed by one-dimensional growth. No influence of blending flexible chain from nylon 6 to the aromatic polyamide on the kinetics of mesophase formation was observed.展开更多
Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubility than chitosan,...Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubility than chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two N-substituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three O-substituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.展开更多
The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid ...The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid crystalline solution for chitin, chitosan, cyanoethyl chitosan and propionyl chitin successively increases as the chain rigidity decreases. Therefore it can be used as an indicator of the chain rigidity.展开更多
The phase behaviour of lanthanide(Ⅲ) dodecylsulphates, Ln(C 12 H 25 SO 4) 3, by thermo optical microscopy using Lawrence penetration technique was investigated. The lyotropic phase behaviour of lanthanide(...The phase behaviour of lanthanide(Ⅲ) dodecylsulphates, Ln(C 12 H 25 SO 4) 3, by thermo optical microscopy using Lawrence penetration technique was investigated. The lyotropic phase behaviour of lanthanide(Ⅲ) dodecylsulphates in ethylene glycol water in mixtures hereof, depends on the composition of the solvent. For pure ethylene glycol and mixtures of ethylene glycol and water three different mesophases are formed, i.e. a lamellar, a cubic and a hexagonal phase, whereas when water is used as solvent no cubic phase is formed. The size of the lanthanide ion has no influence on the mesomorphism of these metallomesogens, although the smaller the lanthanide ion the lower the solubility.展开更多
Theoretical results of normal coordinate analysis of polybenzamide performed with two conformational isomerized models, the cis trans and the all-trans conformation, have been adopted to examine a number of infrared s...Theoretical results of normal coordinate analysis of polybenzamide performed with two conformational isomerized models, the cis trans and the all-trans conformation, have been adopted to examine a number of infrared spectra of films of the polymer treated in a subsequent annealing process and a cooling process. It shows, in this investigation, that two sets of infrared spectral profiles around 1400 cm^(-1) and 900 cm^(-1) behave quite attractively. Their spectral behaviours have been correlated to the conformational defect variation in samples, and reasonably predicted by the normal coordinate calculation.展开更多
Synthesis of conductive polymer poly([thiophene]-[benzo[1,2,3]thiadiazole] [thiophene]) (abbreviated as P(T-Btdaz-T)) was achieved by electrochemical polymerization in hydroxypropyl cellulose (HPC)/N,N-dimethylformami...Synthesis of conductive polymer poly([thiophene]-[benzo[1,2,3]thiadiazole] [thiophene]) (abbreviated as P(T-Btdaz-T)) was achieved by electrochemical polymerization in hydroxypropyl cellulose (HPC)/N,N-dimethylformamide (DMF) in liquid crystal state. The polymer thus obtained shows fingerprint texture, which is derived from helical structure of the HPC in cholesteric liquid crystal state. Fourier transform infrared spectroscopy measurements revealed that the polymer film is P(T-Btdaz-T)/HPC composite. Circular dichroism optical absorption spectroscopy measurements show that the polymer has the optical activity. Next, electrochemical polymerization of 3,4-ethylene-dioxythiophene (EDOT) was carried out in columnar phase liquid crystal. The polymer transcribes the columnar structure and shows optical structure resembling columnar liquid crystal electrolyte solution.展开更多
A series of sandwich-type tungstoarsenates heteropoly compounds with As/W ratio of 4/30, Na16[As4W30M4(H2O)2O112]·XH2O (M = Zn,Cu,Co,Ni,Mn and Cd), have been synthesized for the first time and structurally charac...A series of sandwich-type tungstoarsenates heteropoly compounds with As/W ratio of 4/30, Na16[As4W30M4(H2O)2O112]·XH2O (M = Zn,Cu,Co,Ni,Mn and Cd), have been synthesized for the first time and structurally characterized by elemental analysis, IR and 183W NMR spectra. The crystal structure of Na16[As4W30Cu4(H2O)2O112]·63H2O was determined to be a triclinic system, of P1 symmetry, a = 1.2721(3) nm, b = 2.451 6(5) nm, c = 2.6450(5) nm,展开更多
Critical concentrations of lyotropic liquid crystalline ethylcellulose in more than ten solvents were determined using both Abbe refractometer and polarized microscopy. Critical concentration C-crit of forming Liquid ...Critical concentrations of lyotropic liquid crystalline ethylcellulose in more than ten solvents were determined using both Abbe refractometer and polarized microscopy. Critical concentration C-crit of forming Liquid crystal phase decreased with increasing solubility parameter delta of solvent until approaching the delta of polymer. Although the alcohols used as solvents had the same variation rule, the critical concentration values of their solutions were much higher, due to their excessive large hydrogen bond component of delta. The experiments of using mixed solvents which showed good linear relation between C-crit and delta also proved this rule. A technique of Transmission Optical Analysis was first used to estimate the concentration dependence of critical phase transition temperature T-crit of EC, and a T-C phase diagram could be drawn.展开更多
Au-nanoparticles (size about 2 nm, but not 5 or 15 nm) are capable of effectively incorporating into quasinematic layers of particles of cholesteric liquid-crystalline dispersion formed by double-stranded nucleic acid...Au-nanoparticles (size about 2 nm, but not 5 or 15 nm) are capable of effectively incorporating into quasinematic layers of particles of cholesteric liquid-crystalline dispersion formed by double-stranded nucleic acid molecules of various families (DNA and poly(I)xpoly(C)). This Au-size-dependent process is accompanied by a decrease in amplitudes of abnormal bands in the CD spectra specific to initial cholesteric liquid-crystalline dispersions and simultaneously by an appearance of plasmon resonance band in visible absorption spectrum. The study of properties of particles of cholesteric liquid-crystalline dispersion treated with Au-nanoparticles by means of various physico-chemical methods demonstrates that incorporation of Au-nanoparticles into quasinematic layers of these particles results in two effects: i) it facilitates reorganization of the spatial cholesteric structure of particles, and ii) it induces the formation of Au-clusters in the content of particles. It is not excluded that these effects represent a possible reason for genotoxicity of Au-nanopar- ticles.展开更多
The tribological behavior of oil-in-water emulsions formulated with natural lyotropic liquid crystal(LLC)emulsifiers based on natural sucrose ester was studied for the first time.Polarized optical microscopy,synchrotr...The tribological behavior of oil-in-water emulsions formulated with natural lyotropic liquid crystal(LLC)emulsifiers based on natural sucrose ester was studied for the first time.Polarized optical microscopy,synchrotron radiation small-angle X-ray scattering,wide-angle X-ray scattering,and synchrotron radiation infrared microspectroscopy demonstrated that LLC emulsifiers were tightly ordered at the oil–water interface with a distinct nematic texture.The viscosity of emulsion was observed to change over time.Moreover,the zeta potential and laser particle size distribution verified the emulsion’s satisfactory stability.The frictional shearing test proved that the coefficient of friction of the emulsion versus pure oil decreased by 34.2%.The coefficient of friction of the emulsion with liquid crystal decreased 10.1%versus that without liquid crystal.Although liquid crystal emulsion did not exhibit outstanding anti-wear performance compared with pure oil,its wear volume was 29.4%less than the emulsion without liquid crystal.X-ray photoelectron spectroscopy and scanning electron microscope–energy dispersive X-ray spectroscopy(SEM–EDS)proved that the tribo-film of the emulsion with liquid crystal was formed synergistically by the liquid crystal phase with the base oil.The formulation affecting the lubricant quality was further studied by orthogonal experiments.The resulting Stribeck curve behavior suggested that proper composition with a slightly higher viscosity can better reduce friction in both boundary lubrication and mixed lubrication regimes.The lubrication mechanism indicated that the periodically ordered liquid crystal was transported to the sliding asperity in the form of emulsion droplets,which bored the pressure and released the oil to form a tribo-film.This LLC emulsion is environmentally friendly and potentially non-irritant to the skin.Thus,it has promising application prospects as novel water-based and biological lubricants.展开更多
A polymerized lyotropic liquid crystal monomer of sodium 3,4,5-tris（11-acryloxyundecyloxy）- benzoate was synthesized by a convenient route starting from 3,4,5-trihydroxybenzoic acid via esterification followed by et...A polymerized lyotropic liquid crystal monomer of sodium 3,4,5-tris（11-acryloxyundecyloxy）- benzoate was synthesized by a convenient route starting from 3,4,5-trihydroxybenzoic acid via esterification followed by etherification, acylation and finally neutralization. The chemi- cal structure was confirmed by Fourier transform infrared （FT-IR） and 1H nuclear magnetic resonance spectral analysis. The self-organization behavior of the monomer with deionized water in methanol at room temperature was also demonstrated. The assemblies were char- acterized by polarized optical microscope and X-ray diffraction. The results show that a solution containing 80：20 of the monomer to water was found to be able to self-organize into Lamellar （La） phase and 92：8 with inverted hexagonal （H]I） phase, which was in ac- cordance with the theoretical calculation of critical packing parameter. It suggests that the concentration of the monomer was the key factor to influence assembly structure. Addi- tionally, the acrylate conversion with different photoinitiators and nanostructure retention after polymerization were investigated. The research shows that the acrylate conversion of the monomer with Darocur2959 could reach up to 78% when irradiated by 30 mW/cm2 UV light of 365 nm for 30 min characterized by Real-time FT-IR as well as the sol-gel method. Meanwhile, the La and HII phase nanostructures were both retained after polymerization.展开更多
The lytropic liquid crystals in dodecanic acid diethanolamine (DAD) /n-butanol (C4OH) /octane (n-C8H18) /deuteron (D2O) system were studied to determine the phase regions and were investigated by 2H-NMR spectroscopy,o...The lytropic liquid crystals in dodecanic acid diethanolamine (DAD) /n-butanol (C4OH) /octane (n-C8H18) /deuteron (D2O) system were studied to determine the phase regions and were investigated by 2H-NMR spectroscopy,optical polarizing microscope and small-angle X-ray diffraction (SAXD) methods.The results indicate that the lamellar,hexagonal and cubic liquid crystals all exist in the above system.Keeping the weight ratio of DAD and C4OH constant,the microphase Structure,2H quadruple splitting and the interlayer spacing are all changed with the addition of deuteron.展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant No. 30370945) Guizhou Provincial Governor Foundation (No. 6, 2001).
文摘The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/watersystems has been investigated, and the liquid crystal area has been identified, which covers abouttwo thirds of the whole phase diagram. The liquid crystal structure and behavior have been alsostudied by using polarizing texture, small angle X-ray scattering, ~2H-NMR and rheometer etc. Theresult shows that when the composition of the system changes along the line of AA′ in this largeliquid crystal region, the structural change iscubic→cubic/lamellar→lamellar→larnellar/hexagonal→hexagonal. Meanwhile, we made the firstattempt of systematic study of the rheological properties of the above system. The lattice constantsof cubic and hexagonal liquid crystals are 10.53 and 5.68 nm, respectively.
基金Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB 0470000)the International Partnership Program of Chinese Academy of Sciences project for Grand Challenges(No.307GJHZ2022034GC)+1 种基金the Science and Technology Development Fund of the Pudong New District(No.PKJ2020-N007)for the financial support,and the BL19U2 and BL01B beamlines of the National Facility for Protein Science in Shanghai(NFPS)at Shanghai Synchrotron Radiation Facilitythe support in the SAXS,WAXS,and synchrotron infrared micro-spectroscopy measurements(No.2020-NFPS-PT-004482,h21pr0002).
文摘Lyotropic liquid crystals have lubricating properties due to their ordered assembly and fluidity,whose mesogens are often characterized by amphiphilic properties.Despite the attention that graphene oxide(GO)has been studied as a novel amphiphilic lyotropic mesogen this decade,and GO applied as a lubrication additive has been demonstrated in both oil and water-based systems,little research reveals the interfacial lubrication of GO liquid crystals yet.This work reports that GO aqueous dispersion can form lyotropic liquid crystals above a specific critical concentration of 5.00 mg/mL,providing a form of stable water-based lubricant,which can keep stable for several months and can reduce friction by 37.3%and wear by 25.24%.The liquid crystal phase was verified by polarizing microscope and synchrotron radiation small-angle X-ray scattering,and its rheological properties and viscoelasticity were studied by interfacial rheometer.The formation of lyotropic liquid crystals can enhance the stability of GO aqueous dispersions at high density,simultaneously ensuring friction decrease and anti-wear effect.It is attributed to the stable nematic network by the ordered GO sheets.The ordered assembly structure bears vertical shear force,therefore,reducing the wear.It is also assumed that the wide lateral size of graphene oxide promotes the nematic phase thus smoothes the graphene oxide film composed spontaneously under the coincidence of lamellar liquid crystal and 2D layered material.Through this work,the interlayer lubrication of GO was optimized,and the problem of GO dispersion sedimentation was solved by self-assembly.The range of interfacial lubrication of GO aqueous dispersion has been expanded and the synergistic effect is conducive to the environmentally friendly lubricants.
基金the National Natural Science Foundation of China (Grant No.20073025), Key Teacher Fund and CSC of Ministry of the Education, State Major Basic Research Project of China and Israel Science Foundation.
文摘The organic lyotropic liquid crystal with long-range structural order is used as template to assemble inorganic/organic hybrid by doping pre-fabricated Ag nanoparticles. The lamellar hybrid with both hydrophilic and hydrophobic particles doped simultaneously is realized for the first time. The change of template structure after doping and the stability origin of dual-doped system are characterized by small angle X-ray scattering and polarized optical microscopy. Results show that the interaction and space matching between surfactant bilayers and doped particles are key factors to obtain stable hybrid.
基金Supported by National Natural Science Foundation(No.0 5 1730 0 3) Beijing Science and Technology New Star Program(No.H0 10 4 10 0 10 112 ) and Im portant Natural Science Foundation of Beijing(No.2 0 310 0 1) .
文摘The polymerization of amphiphilic self assemblies is a promising method to synthesize nano structured materials with novel properties. These materials have many attractive features for their application in biomedical area and materials science, such as catalysis, separation, surface modification, and therapeutics areas. A general review on the polymerization of lipids and surfactant self assemblies to amphiphilic self assemblies is given in this paper with 49 references. The polymerization and the subsequently resulted structure of lipids in different morphologies are summarized. The polymerization of polymerizable surfactants(surfmers) in emulsion and liquid crystalline phases are also discussed. The potential application of new nano porous materials is briefly described.
基金supported by the National Natural Science Foundation of China (Nos. 21364017 and 21274119)the Yunnan Natural Science Foundation (No. 2013FA007)Scholarship Award for Excellent Doctoral Student of Yunnan Province and Foundation (No. ynuy201418)
文摘Novel T-shaped bolaamphiphiles consisting of a bent 2,5-diphenylethynyl thiophene rigid core with two terminal glycerol units and a lateral n-alkyl chain have been synthesized via Kumuda and Sonogashira coupling reactions as key steps. Their liquid crystalline behavior was investigated by polarizing optical microscopy （POM）, differential scanning calorimetry （DSC）, and X-ray diffraction （XRD）. All such bolaamphiphiles can self-organize into square honeycomb LC phases with p4rnm symmetries in the presence of water, UV and PL measurements indicate fluorescent properties making them potential candidates for application in fluorescence sensor devices.
基金support of the National Nat-ural Science Foundation of China(21875129).
文摘Lyotropic liquid crystals(LLCs)produced by the self-assembly of surfactant in water represent an important class of highly ordered soft materials that have a wide range of applications.This study investigates the LLCs formed by a zwitterionic surfactant(tetradecyldimethylaminoxide,C 14 DMAO)in water.The organization of C 14 DMAO within the LLCs was determined based on a detailed analysis of small-angle X-ray scattering measure-ments and polarized microscopy observations of a typical sample.Additional to the singe-phase region,which has a hexagonal organization,several two-phase regions were observed,exhibiting the coexistence of hexago-nal/cubic,cubic/lamellar,and hexagonal/lamellar phases.The phase behavior showed an obvious dependence on temperature,with more pronounced two-phase regions at lower temperatures.Using the LLCs as a matrix,Au nanospheres,nanoellipsoids,and nanorods were prepared without requiring additional reducing reagents.These three-and one-dimensional Au nanomaterials could be converted to two-dimensional plates via the introduc-tion of a small amount of cationic surfactant to the LLCs,such as cetyltrimethylammonium bromide(CTAB)and 1-hexadecyl-3-methylimidazolium bromide([C 16 MIm]B),which showed pronounced surface-enhanced Raman scattering activity towards solid rhodamine.The LLCs loaded with CTAB(or[C 16 MIm]B)and HAuCl 4 exhibited slightly different structures and mechanical strength from the original LLCs,thereby forming a new class of highly crowded colloidal materials.
基金This work was supported by Academia Sinica selected Research Program and National Natural Science Foundation of China
文摘The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which suggests the nucleation followed by one-dimensional growth. No influence of blending flexible chain from nylon 6 to the aromatic polyamide on the kinetics of mesophase formation was observed.
基金Financial support by Laboratory of Cellulose and Lignocellulosics Chemistry, Academia Sinica
文摘Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubility than chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two N-substituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three O-substituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.
基金Supported by the Laboratory of Cellulose and Lignocellulosics Chemistry. Chinese Academy of Sciences and National Natural Science Foundation. China
文摘The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid crystalline solution for chitin, chitosan, cyanoethyl chitosan and propionyl chitin successively increases as the chain rigidity decreases. Therefore it can be used as an indicator of the chain rigidity.
文摘The phase behaviour of lanthanide(Ⅲ) dodecylsulphates, Ln(C 12 H 25 SO 4) 3, by thermo optical microscopy using Lawrence penetration technique was investigated. The lyotropic phase behaviour of lanthanide(Ⅲ) dodecylsulphates in ethylene glycol water in mixtures hereof, depends on the composition of the solvent. For pure ethylene glycol and mixtures of ethylene glycol and water three different mesophases are formed, i.e. a lamellar, a cubic and a hexagonal phase, whereas when water is used as solvent no cubic phase is formed. The size of the lanthanide ion has no influence on the mesomorphism of these metallomesogens, although the smaller the lanthanide ion the lower the solubility.
文摘Theoretical results of normal coordinate analysis of polybenzamide performed with two conformational isomerized models, the cis trans and the all-trans conformation, have been adopted to examine a number of infrared spectra of films of the polymer treated in a subsequent annealing process and a cooling process. It shows, in this investigation, that two sets of infrared spectral profiles around 1400 cm^(-1) and 900 cm^(-1) behave quite attractively. Their spectral behaviours have been correlated to the conformational defect variation in samples, and reasonably predicted by the normal coordinate calculation.
文摘Synthesis of conductive polymer poly([thiophene]-[benzo[1,2,3]thiadiazole] [thiophene]) (abbreviated as P(T-Btdaz-T)) was achieved by electrochemical polymerization in hydroxypropyl cellulose (HPC)/N,N-dimethylformamide (DMF) in liquid crystal state. The polymer thus obtained shows fingerprint texture, which is derived from helical structure of the HPC in cholesteric liquid crystal state. Fourier transform infrared spectroscopy measurements revealed that the polymer film is P(T-Btdaz-T)/HPC composite. Circular dichroism optical absorption spectroscopy measurements show that the polymer has the optical activity. Next, electrochemical polymerization of 3,4-ethylene-dioxythiophene (EDOT) was carried out in columnar phase liquid crystal. The polymer transcribes the columnar structure and shows optical structure resembling columnar liquid crystal electrolyte solution.
文摘A series of sandwich-type tungstoarsenates heteropoly compounds with As/W ratio of 4/30, Na16[As4W30M4(H2O)2O112]·XH2O (M = Zn,Cu,Co,Ni,Mn and Cd), have been synthesized for the first time and structurally characterized by elemental analysis, IR and 183W NMR spectra. The crystal structure of Na16[As4W30Cu4(H2O)2O112]·63H2O was determined to be a triclinic system, of P1 symmetry, a = 1.2721(3) nm, b = 2.451 6(5) nm, c = 2.6450(5) nm,
基金The project was supported by Return Student Foundation of the State Education Commission of China
文摘Critical concentrations of lyotropic liquid crystalline ethylcellulose in more than ten solvents were determined using both Abbe refractometer and polarized microscopy. Critical concentration C-crit of forming Liquid crystal phase decreased with increasing solubility parameter delta of solvent until approaching the delta of polymer. Although the alcohols used as solvents had the same variation rule, the critical concentration values of their solutions were much higher, due to their excessive large hydrogen bond component of delta. The experiments of using mixed solvents which showed good linear relation between C-crit and delta also proved this rule. A technique of Transmission Optical Analysis was first used to estimate the concentration dependence of critical phase transition temperature T-crit of EC, and a T-C phase diagram could be drawn.
文摘Au-nanoparticles (size about 2 nm, but not 5 or 15 nm) are capable of effectively incorporating into quasinematic layers of particles of cholesteric liquid-crystalline dispersion formed by double-stranded nucleic acid molecules of various families (DNA and poly(I)xpoly(C)). This Au-size-dependent process is accompanied by a decrease in amplitudes of abnormal bands in the CD spectra specific to initial cholesteric liquid-crystalline dispersions and simultaneously by an appearance of plasmon resonance band in visible absorption spectrum. The study of properties of particles of cholesteric liquid-crystalline dispersion treated with Au-nanoparticles by means of various physico-chemical methods demonstrates that incorporation of Au-nanoparticles into quasinematic layers of these particles results in two effects: i) it facilitates reorganization of the spatial cholesteric structure of particles, and ii) it induces the formation of Au-clusters in the content of particles. It is not excluded that these effects represent a possible reason for genotoxicity of Au-nanopar- ticles.
基金We thank the Pudong New Area Science&Technology Development Fund(Grant No.PKJ2020-N007)the BL19U2 and BL01B beamlines of the National Facility for Protein Science in Shanghai(NFPS)at Shanghai Synchrotron Radiation Facility,China,for the support in the SAXS,WAXS,and synchrotron infrared micro-spectroscopy measurements(Grant Nos.2020-NFPS-PT-004482 and h21pr0002).
文摘The tribological behavior of oil-in-water emulsions formulated with natural lyotropic liquid crystal(LLC)emulsifiers based on natural sucrose ester was studied for the first time.Polarized optical microscopy,synchrotron radiation small-angle X-ray scattering,wide-angle X-ray scattering,and synchrotron radiation infrared microspectroscopy demonstrated that LLC emulsifiers were tightly ordered at the oil–water interface with a distinct nematic texture.The viscosity of emulsion was observed to change over time.Moreover,the zeta potential and laser particle size distribution verified the emulsion’s satisfactory stability.The frictional shearing test proved that the coefficient of friction of the emulsion versus pure oil decreased by 34.2%.The coefficient of friction of the emulsion with liquid crystal decreased 10.1%versus that without liquid crystal.Although liquid crystal emulsion did not exhibit outstanding anti-wear performance compared with pure oil,its wear volume was 29.4%less than the emulsion without liquid crystal.X-ray photoelectron spectroscopy and scanning electron microscope–energy dispersive X-ray spectroscopy(SEM–EDS)proved that the tribo-film of the emulsion with liquid crystal was formed synergistically by the liquid crystal phase with the base oil.The formulation affecting the lubricant quality was further studied by orthogonal experiments.The resulting Stribeck curve behavior suggested that proper composition with a slightly higher viscosity can better reduce friction in both boundary lubrication and mixed lubrication regimes.The lubrication mechanism indicated that the periodically ordered liquid crystal was transported to the sliding asperity in the form of emulsion droplets,which bored the pressure and released the oil to form a tribo-film.This LLC emulsion is environmentally friendly and potentially non-irritant to the skin.Thus,it has promising application prospects as novel water-based and biological lubricants.
文摘A polymerized lyotropic liquid crystal monomer of sodium 3,4,5-tris（11-acryloxyundecyloxy）- benzoate was synthesized by a convenient route starting from 3,4,5-trihydroxybenzoic acid via esterification followed by etherification, acylation and finally neutralization. The chemi- cal structure was confirmed by Fourier transform infrared （FT-IR） and 1H nuclear magnetic resonance spectral analysis. The self-organization behavior of the monomer with deionized water in methanol at room temperature was also demonstrated. The assemblies were char- acterized by polarized optical microscope and X-ray diffraction. The results show that a solution containing 80：20 of the monomer to water was found to be able to self-organize into Lamellar （La） phase and 92：8 with inverted hexagonal （H]I） phase, which was in ac- cordance with the theoretical calculation of critical packing parameter. It suggests that the concentration of the monomer was the key factor to influence assembly structure. Addi- tionally, the acrylate conversion with different photoinitiators and nanostructure retention after polymerization were investigated. The research shows that the acrylate conversion of the monomer with Darocur2959 could reach up to 78% when irradiated by 30 mW/cm2 UV light of 365 nm for 30 min characterized by Real-time FT-IR as well as the sol-gel method. Meanwhile, the La and HII phase nanostructures were both retained after polymerization.
文摘The lytropic liquid crystals in dodecanic acid diethanolamine (DAD) /n-butanol (C4OH) /octane (n-C8H18) /deuteron (D2O) system were studied to determine the phase regions and were investigated by 2H-NMR spectroscopy,optical polarizing microscope and small-angle X-ray diffraction (SAXD) methods.The results indicate that the lamellar,hexagonal and cubic liquid crystals all exist in the above system.Keeping the weight ratio of DAD and C4OH constant,the microphase Structure,2H quadruple splitting and the interlayer spacing are all changed with the addition of deuteron.
