The Isoelectric Point and the Points of Zero Charge of Fe-Al-Mg Hydrotalcite-like Compounds

The relation of the isoelectric point (IEP) and the point of zero net charge (PZNC) of the hydrotalcite-like compounds was discussed. It was found that the IEP does not equal to the PZNC and the IEP is higher than the PZNC. The structural positive charges existing in the HTlc,which cause the difference between the IEP and the PZNC. The effects of the structural positive charges of the HTlc on its IEP and PZNC are the same as the specific adsorption of metal cations.     

Dynamic Study of Gemini Surfactant and Single-chain Surfactant at Air／Water Interface

Molecular dynamics (MD) simulation are used to study the properties of gemini surfactant of ethyl-α,ω-bis(dodecyldimethylammonium bromide) (C12C2C12) and dodecyl-trimethylammonium bromide (DTAB) at the air/water interface, respectively. In the two systems,t he surfactant concentrations are both 28 wt.%, and other conditions are also the same. After reaching the thermodynamic equilibrium, the concentration profiles, the radial distributions functions (RDF) and the mean squared displacement (MSD) are investigated. The results reveal that the surface activity of C12C2C12 surfactant is higher than DTAB surfactant.     

Intrinsic Surface Reaction Constant in 1-pK Model of Mg-Fe Hydrotalcite-like Compounds

The relationship among intrinsic surface reaction constant (K) in 1-pK model, point of zero net charge (PZNC) and structural charge density (σst) for amphoteric solid with structural charges was established in order to investigate the effect of σst on pK. The theoretical analysis based on 1-pK model indicates that the independent PZNC of electrolyte concentration (c) exists for amphoteric solid with structural charges. A common intersection point (CIP) should appear on the acid-base titration curves at different c, and the pH at the CIP is pHPZNC. The pK can be expressed as pK=-pHPZNC log[(1 2αPZNC)/(1-2αPZNC)], where αPZNC≡σst/eNANs, in which e is the elementary charge, NA the Avogadro‘s constant and Ns the total density of surface sites. For solids without structural charges, pK=-pHPZNC. The pK values of hydrotalcite-like compounds (HTlc) with general formula of [Mg1-xFex(OH)2](Cl,OH)x were evaluated. With increasing x, the pK increases, which can be explained based on the affinity of metal cations for H^- or OH^- and the electrostatic interaction between charging surface and H^- or OH^-.     

In Situ Fabrication of ZnS Semiconductor Nanoparticles in Layered Organic-inorganic Solid Template

Ordered ZnS semiconductor nanoparticles were in situ synthesized in metal halide perovskite organic/inorganic layered hybrids (CnH2n 1NH3)2ZnCl4 (n=10 and 12) by reaction of their spin-casting films with H2S gas. Transmission electron microscopy, UV-vis spectroscopy and small-angle X-ray diffraction were used to characterize the morphology and the structure of formed nanoparticles. Obtained results indicate an effective way to incorporate functional inorganic nanoparticles into structured organic matrices.     

An Efficient Route to Prepare Metal Organosols by Phase Transfer Procedure

Silver and gold organosols are easily prepared by transferring nanoparticles from aqueous phase into isooctane with high efficiency (＞90%). Concentrations of sodium oleate and magnesium chloride have crucial effects on the transfer efficiency. Based on the UV-visible absorption spectra, TEM micrographs of nanoparticles, as well as molecular modeling calculation about the adsorption conformation of sodium oleate molecules, a possible phase transfer mechanism is proposed.     

Study of the Electrical Double Layer of a Spherical Micelle: Functional Theoretical Approach

The electrical double layer theory is the base of the colloid stability theory (DLVO theory), and the PB eq. is a key to the study of the layer1,2. For a spherical particle, the PB eq. is (1) where and are the dielectric constant of the medium, the valence of ions, the elementary charge, the concentration of ions far away from the particle, the Boltzmann's constant and the temperature of the system, respectively. Since this eq. is a second order nonlinear differential one, only the anal…     

谷氨酸低分子量有机凝胶的药物控制释放行为

低分子量的有机胶凝剂组装形成的有机凝胶可应用于药物缓释体系.本研究中,使用亲水的钙黄绿素和疏水的布洛芬为模型分子,研究其在谷氨酸衍生物有机凝胶体系中的缓释行为.研究表明,与药物分子与有机胶凝剂简单混合的体系相比,亲水或疏水的药物分子在有机凝胶体系中的释放速度显著减缓.SEM的研究发现药物粒子嵌入在有机凝胶的三维网络中,因此,有机凝胶的三维网络结构可认为是实现药物缓慢释放的基质,药物分子从网络中的释放受限导致了其从有机凝胶中的缓释行为.     

光声光谱技术在层状物质的逐层分析研究中的应用——Ⅰ.光声相位精细谱技术

本文提出光声相位精细谱法(PAPFS)。通过对层状物初始态光声相位扫描和对由此产生的PAPFS曲线的解析,可获取各层与光学热学和空间坐标相关的有价值的信息。本文用该法对彩色相纸作了逐层分析,并将结果与电镜作了比较。与PAPFS相关的层状物光声理论将在本文第Ⅱ部分中涉及。     

CONTROLLING THE 3D NANOSCALE ORGANIZATION OF BULK HETEROJUNCTION POLYMER SOLAR CELLS

In this study,the three dimensional nanoscale organization in the photoactive layers of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM) is revealed by transmission electron tomography.After annealing treatment,either at elevated temperature or during slow solvent evaporation,nanoscale interpenetrating networks are formed with high crystalline order and favorable concentration gradients of both components through the thickness of the photoactive layer.Such a tailored morphology acco...     

Molecular Arrangement of a Bolaamphiphilic Anthrancene Derivative in Langmuir-Blodgett Film

Langmuir monolayer at the air/water interface is the basis to understand the molecular arrangement and to fabricate the organized molecular films1. Bolaamphiphiles describes the molecules in which two head functional groups are linked by one or two hydrophobic chains2,3. In comparison with the one-headed amphiphile, abundant configurations of Langmuir monolayer are expected in bolaamphiphiles. Generally, three kinds of configurations of the Langmuir monolayers of bolaamphiphile at the air/w…