Aspirin Degradation in Mixed Polar Solvents

Degradation studies were conducted on 0.2% w/v aspirin liquid formulation in a wide range of water-propylene glycol mixtures and water-triethylene glycol diacetate mixtures at four temperatures. The effect of a surfactant, polyoxyethylene (20) sorbitan monolaurate, on aspirin stability was also investigated. There was a linear relationship between water content and degradation rate constants. The surfactant increased aspirin degradation in all formulations. Formulations containing the higher concentration of the surfactant showed the greater aspirin decomposition.     

Aggregation of Endometallofullerene Y@C82 in Polar Solvents

Having studied the optical absorption, fluorescence spectra and dynamic light scattering (DLS) of solutions of Y-EMF in polar solvents, we demonstrated for the first time that the endohedral metallofullerenes (EMF) forms nanoparticles, the mean size of which ranges up to 100 nm.     

Aggregation of Endometallofullerene Y@C82 in Polar Solvents

Abstract

Having studied the optical absorption, fluorescence spectra and dynamic light scattering (DLS) of solutions of Y‐EMF in polar solvents, we demonstrated for the first time that the endohedral metallofullerenes (EMF) forms nanoparticles, the mean size of which ranges up to 100 nm.     

混合溶剂体系电子墨水的制备

以改性的二氧化钛颗粒为白色颜料颗粒,油溶黑为对比色染料,byk系列分散剂为电荷控制剂,邻二氯苯和二甲苯的混合溶剂体系为分散介质,制备电子墨水,深入研究电子墨体系的分散介质对电子纸显示的影响。邻二氯苯和二甲苯溶剂配比为1：1时,组装的电子纸显示器件黑白显示效果最佳。     

Studies on Hydrogen-Bond Interactions in Ternary Mixtures of Polar Solvents by Dielectric Constant Measurements

The static dielectric constant of equimolar mixtures of formamide+N,N-dimethylformamide and formamide+2-aminoethanol mixed with water, ethyl alcohol, dimethylsulphoxide, and 1,4-dioxane were measured over the entire composition range at 303.15 K. The concentration-dependent non-linear behavior of the dielectric constant of the ternary mixtures confirms the formation of hydrogen-bond interactions between the mixture constituents. The excess dielectric-constant values of the mixtures were determined and discussed in view of the strength of hydrogen-bond interactions and the nature of dipolar ordering. It is found that in ternary mixtures, water acts as a structure-maker and ethyl alcohol, dimethylsulphoxide, and 1,4-dioxane act as structure-breakers for the equimolar formamide+N,N-dimethylformamide and formamide+2-aminoethanol binary structures.     

可循环混合溶剂分离水稻秸秆纤维素

粉碎的水稻秸秆经水煮和抽提预处理后,采用乙二醇(EG)和水的混合体系(体积比9∶1)为溶剂,在酸或碱催化作用下,分离得到纤维素,同时回收木质素和半纤维素;对所得样品的组分含量、晶体结构、微观形貌等进行了分析。结果表明:经水煮和抽提预处理后,秸秆纤维束状结构变得疏松;在0.1mol/L的硫酸催化下,经混合溶剂处理所得样品的综纤维素含量达到86.59%(其中纤维素含量为83.09%),酸不溶木质素含量为3.70%;相同条件下,以0.1mol/L氢氧化钠为催化剂,所得样品中酸不溶木质素含量为4.21%。研究还发现,混合溶剂可高效回收并循环使用。基于实验结果和结论分析,对催化剂可能的作用机理解释为:在适当浓度的酸或碱作用下,木质素的重聚合被有效抑制,从而促进了其在混合溶剂中溶解,并使其从秸秆组织中分离。     

Solubilities of Carbon Dioxide in Aqueous Potassium Carbonate Solutions Mixed with Physical Solvents

The solubilities of carbon dioxide in aqueous potassium carbonate (K₂CO₃) solutions mixed with physical solvents were measured at 298.2 and 323.2 K with a CO₂ partial-pressure range of 5 kPa to 2 MPa. 1,2-propanediol and propylene carbonate were selected as physical solvents. The aqueous solutions treated in this study were 5 mass% K₂CO₃–15 mass% 1,2-propanediol, 5 mass% K₂CO₃–30 mass% 1,2-propanediol, 5 mass% K₂CO₃–7.5 mass% propylene carbonate, and 5 mass% K₂CO₃–15 mass% propylene carbonate. The experimental solubility results were presented by the mole ratio of CO₂ and K₂CO₃ contained in the liquid mixture. The addition of 1,2-propanediol to 5 mass% K₂CO₃ solution lowered the solubility of CO₂ at constant temperature and pressure conditions within the CO₂ partial-pressure range of 5 kPa to 2 MPa. In the case of propylene carbonate, the addition of propylene carbonate increased the experimental solubilities in the region of low CO₂ partial pressures and decreased as the CO₂ partial pressure was increased above atmospheric. The solubilities of CO₂ decreased with increasing temperature in the range of 298.2 to 323.2 K.     

利用混合溶剂实现钙钛矿材料微观结构和光电性能优化

采用纯N, N-二甲基甲酰胺(DMF)溶剂、纯二甲基亚砜(DMSO)溶剂以及DMSO/DMF不同体积比例混合溶剂制备钙钛矿(CH₃NH₃PbI₃)薄膜, 并系统研究了不同溶剂对钙钛矿薄膜微结构及光电特性的影响。结果表明, 随着DMSO在混合溶剂中比例增加, 钙钛矿薄膜平均晶粒尺寸增大, 碘化铅(PbI₂)残留量降低, 同时薄膜中有序的钙钛矿晶体所占比例呈现先增大后减小的趋势, 并且当DMSO占混合溶剂体积比为60%时达到最大。薄膜Urbach能, 载流子寿命以及PbI₂含量之间的关系表明, 微量的PbI₂可有效钝化钙钛矿薄膜的缺陷。经过优化后(DMSO占混合溶剂体积比为30%), 钙钛矿太阳电池的光电转换效率达到15.1 % (V_OC=0.99 V; J_SC=20.9 mA/cm²; FF=0.73)。     

Conjugated‐Polyelectrolyte‐Functionalized Reduced Graphene Oxide with Excellent Solubility and Stability in Polar Solvents

Conjugated‐polyelectrolyte (CPE)‐functionalized reduced graphene oxide (rGO) sheets are synthesized for the first time by taking advantage of a specially designed CPE, PFVSO₃, with a planar backbone and charged sulfonate and oligo(ethylene glycol) side chains to assist the hydrazine‐mediated reduction of graphene oxide (GO) in aqueous solution. The resulting CPE‐functionalized rGO (PFVSO₃‐rGO) shows excellent solubility and stability in a variety of polar solvents, including water, ethanol, methanol, dimethyl sulfoxide, and dimethyl formamide. The morphology of PFVSO₃‐rGO is studied by atomic force microscopy, X‐ray diffraction, and transmission electron microscopy, which reveal a sandwich‐like nanostructure. Within this nanostructure, the backbones of PFVSO₃ stack onto the basal plane of rGO sheets via strong π–π interactions, while the charged hydrophilic side chains of PFVSO₃ prevent the rGO sheets from aggregating via electrostatic and steric repulsions, thus leading to the solubility and stability of PFVSO₃‐rGO in polar solvents. Optoelectronic studies show that the presence of PFVSO₃ within rGO induces photoinduced charge transfer and p‐doping of rGO. As a result, the electrical conductivity of PFVSO₃‐rGO is not only much better than that of GO, but also than that of the unmodified rGO.     

Origins of High Performance and Degradation in the Mixed Perovskite Solar Cells

The origins of the high device performance and degradation in the air are the greatest issues for commercialization of perovskite solar cells. Here this study investigates the possible origins of the mixed perovskite cells by monitoring defect states and compositional changes of the perovskite layer over the time. The results of deep‐level transient spectroscopy analysis reveal that a newly identified defect formed by Br atoms exists at deep levels of the mixed perovskite film, and its defect state shifts when the film is aged in the air. The change of the defect state is originated from loss of the methylammonium molecules of the perovskite layer, which results in decreased J_SC, deterioration of the power conversion efficiency and long‐term stability of perovskite solar cells. The results provide a powerful strategy to diagnose and manage the efficiency and stability of perovskite solar cells.     

乙醇/水混合溶剂沉淀制备纳米SrF_2及其粒径控制

本文采用水/乙醇混合溶剂沉淀法,制备了不同粒径的SrF2纳米粉体,也在不同pH值的水溶液和不同表面活性剂CTAB、SDS的水溶液中,研究制备了纳米SrF2。用XRD、TEM观测分析了粉体的粒径和形貌。在纯水和水/乙醇体积比3∶1,1∶1,3∶5,1∶4的混合溶剂中,获得SrF2沉淀的粒径分别为32nm,19nm,23nm,16nm和13nm,粒径总体上随混合溶剂中乙醇含量升高而减小,其分散性和形貌规则性也随乙醇含量升高而变好。水溶液的pH值和表面活性剂对SrF2沉淀粒径无明显影响,相比之下,混合溶剂对粒径的影响显著。     

Polar nanoclusters in relaxors

The central problem in the physics of relaxors is the nature of the polar nanoclusters. Whereas relaxors are homogeneous at high enough temperatures, polar nanoregions immersed in a neutral matrix are formed below a certain temperature T _b . This should lead to a two component system. Here we present direct microscopic evidence for the two component nature of relaxors. We show that the chemical shift perturbed ²⁰⁷ Pb NMR spectra of these systems consist of an isotropic component corresponding to a spherical glassy matrix which does not respond to an applied electric field, and an anisotropic component, corresponding to frozen out polar nanoclusters which order in a strong enough electric field, forming a ferroelectric phase. This is as well reflected in the dynamic properties where the relaxation time distribution function starts to become asymmetric with decreasing temperature and a second maximum—which is never seen in dipolar glasses and is obviously due to polar clusters—appears on further cooling. We also show that the basic difference between dipolar glasses and relaxors is the fact that polar nanoclusters can be oriented in a strong enough electric field and a ferroelectric phase can be induced. This is not the case in dipolar glasses where the response is due to single dipoles which can not be ordered by applied electric fields.     

Mixed Phase Anatase/rutile Titanium Dioxide Nanotubes for Enhanced Photocatalytic Degradation of Methylene-blue

Nano-Micro Letters - Titanium dioxide Nanotubes (TNTs) prepared by electroless deposition have been annealed at air ambient and low temperature. As a result, the anatase/rutile phase composition of...     

Polar Langmuir-Blodgett films

An optical and electro-optical technique is described for measuring the orientational order parameters $\text{P}\text{(}\text{cos}{}^{\mathrm{n}}\text{θ)}$ of Langmuir-Blodgett films (where θ is the angle between the long molecular axis and the normal to the film plane and $\text{P}$_n are the Legendre polynomials for n = 1, 2, 3, 4). Using these data the orientational distribution function $\text{F}$ (θ) was constructed.Polar multilayers $\text{(}\text{cos}\text{θ}\text{,}\text{cos}{}^3\text{θ}\text{≠ 0)}$ of the X and Z types were obtained from amphiphilic azony compounds. These layers were shown to have a macroscopic electrical polarization P = 10^-6 C cm^-2 and, as a result, they exhibit pyroelectric and piezoelectric properties as well as the linear electro-optical (Stark) effect.     

氧化锌压敏陶瓷中氧化锌晶粒极性生长现象的研究

发现了ZnO压敏陶瓷中的锥状或柱状“突起物”现象.通过能谱发现“突起物”的物质构成是ZnO,而且是ZnO晶粒生长形成的实体,并非气体在ZnO中形成的气泡.进一步论证了这种现象是ZnO极性生长造成的,并从内因和外因两个方面进行了分析.内因是ZnO的极性晶格结构和结晶形态,外因是ZnO压敏陶瓷中Bi₂O₃液相提供了极性生长得以显现的物化环境,并且通过单独添加Bi₂O₃的97mol%ZnO+3mol%Bi₂O₃配方和100mol%纯ZnO配方制备样品进行对比实验,验证了Bi₂O₃的作用.     

Solubility of C70 in Organic Solvents

The solubility of C⁷⁰ in various organic solvents has been measured at 303 K for the first time. The solubilities vary from 2 μg/ml in pentane to 36 mg/m1 in o-dichlorobenzene. The solubility is correlated with solvent properties such as Hildebrand solubility parameter and polarisability. The solubility parameter shows good correlation with the solubility for most of the organic solvents studied, with the exception of carbon disulphide and o-dichlorobenzene. The polarisability parameter also explains the wide range of solubility in various organic solvents. However, both the solvent parameters do not satisfactorily explain the trend in the observed solubility over the entire range of solvents.