两亲分子结构对铜网表面生长的Cu2S纳米材料形貌的影响

观察到两亲分子的结构对铜网表面生长的Cu2S-维纳米材料的形貌有较大的影响，含羧酸的强亲水型两亲分子——N-硬脂酰-L-谷氨酸有助于形成纳米线，而把两个羧基全部转化为酯基后．则倾向于形成具有分形结构的纳米带。     

两亲嵌段树枝状分子Gx-PBE-b-Gx-PMPA(OH)x2的合成及多重氢键作用

合成了1~3代的嵌段树枝状分子聚苄醚-聚脂肪酯(Gx-PBE-b-Gx-PMPA, x=1,2,3)和两亲嵌段树枝状分子聚苄醚-周边含羟基的聚脂肪酯[Gx-PBE-b-Gx-PMPA(OH)x2, x=1,2,3]. PMPA(OH)x2-树枝片(Dendron)段周边的羟基数目分别是2, 4和8. 通过1H NMR, 13C NMR, FTIR和基质辅助激光解吸附电离飞行时间质谱(MALDI-TOF)(或场解析电离质谱)技术表征了Gx-PBE-b-Gx-PMPA和Gx-PBE-b-Gx-PMPA(OH)x2的结构. 同时, 采用变温FTIR光谱研究了在两亲嵌段树枝状分子中形成的氢键模式. 结果表明, 随着树枝片代数的增加, 两亲嵌段树枝状分子内趋向于形成作用较弱的分子内氢键, 说明形成3代两亲嵌段树枝状分子的三维结构削弱了羟基形成分子间氢键的能力.     

含C60球两亲分子有序聚集体研究

综合评述了C60两亲分子有序聚集体的形成、结构及聚集体演变规律,介绍了含C60球两亲分子有序聚集体结构的冷冻刻蚀电子显微镜和电子显微镜、小角度中子散射、小角度X光散射、激光光散射以及聚集体结构模型的研究结果.     

单烷基乙二胺稀水溶液头基相互作用自组装形成 双分子膜

提出普通表面活性剂(单链两亲分子)亲水头基相互作用诱导疏水尾链平行聚集形成双分子膜的新机制。设计和合成了系列单烷基取代乙二胺C~nH~2~n~+~1NHC~2H~4NH~2(n=8,12,14,16,18)。通过电镜形态,分散液凝胶/液晶相变和对应铸膜的二维双层结构,表明单链两亲分子头基相互作用和脂链引入刚性片断一样,两者形成的双分子膜具有类似的结构和性能;展示了各体系取代乙二胺双层结构和性能的密切联系。指出了广泛认同的单链两亲分子形成双分子膜必须引入刚性片断的单一成膜机制的片面性,为组装新一类功能头基表面活性剂双分子膜独辟蹊径。     

囊泡的形成与两亲分子结构

本文综述了可以形成囊泡的各类两亲分子的结构特点和形成条件，并对某些体系中囊泡的形成机理进行了探讨。     

酸碱开关两亲分子的研究进展

酸碱开关两亲分子又称为pH敏感两亲分子,结构中常含有酸性或者碱性基团,通过接受或者给予质子使两亲分子的性质发生变化。近十几年,酸碱开关两亲分子由于良好的生物相容性而发展迅猛,在基因载体、药物缓释、油水乳化等很多领域有很好的应用潜力。本文对酸碱开关两亲分子在这些领域中的应用、作用机理进行了分析与讨论,并对酸碱开关两亲分子的发展进行了展望。     

含Schiff碱基囊泡双分子膜的聚集结构与相变

研究表面活性剂分子在水溶液中的聚集行为对模拟生物膜功能和研究分子间相互作用具有重要意义"'．用于形成囊泡双分子层的表面活性剂主要是类似天然磷脂的双烷基链两亲分子,单烷基链两亲分子在引人刚性基团时亦可形成双分子膜k'．含SChiff碱基两亲分子在水溶液中的聚集性质及间、尾链长度对SChiff碱基构象的影响已有报道"'．本文报道了这类分子的另一种重要成膜性质,即改变制备条件,可选择性地得到不同聚集结构和相变温度的双分子膜·实验中所用成膜分子为：CH。（CH。）。;OPh-N-CH－PhO（CH;）n;N"（CH。）。Br－（m-4;n-…     

二维有机组装体的可控制备

二维有机组装体是一类具有特殊形貌和性质的有序结构, 有可能带来新功能和光电子领域的潜在应用, 但如何实现二维有机组装体的可控制备是尚待解决的问题. 针对这一问题, 我们通过对构筑基元的理性设计, 调控分子间的相互作用, 发展了三种可控制备二维有机组装体的新方法: (1)利用疏水有机阴离子作为Bola型两亲分子的抗衡离子, 能够削弱亲水头基间的静电排斥作用, 从而诱导两亲分子的组装结构从一维向二维转变; (2)基于非共价键形成超两亲分子, 通过设计和控制超两亲分子的拓扑结构, 简便有效地实现二维组装体的制备; (3)通过共价修饰或引入新的非共价键, 以限制三维结构在某一方向上的生长, 从而降低三维结构的维度, 也能实现二维组装体的可控制备. 未来, 上述研究有望进一步拓展, 并实现功能二维有机组装体的构筑.     

双头基两亲分子研究进展

本文介绍了双头基两亲分子的结构特征与性质, 概述了由双头基两亲分子在气液界面形成的单分子膜以及在体相中形成的囊泡的特征, 并介绍了这类两亲分子在催化、生物矿化、药物缓释、膜破解以及纳米材料等方面的应用研究。对其研究前景进行了展望。     

超两亲分子:可控组装与解组装

与基于共价键的两亲性分子相对照,超两亲分子系指基于非共价键构筑的两亲分子.基于超分子体系的分子工程学的思想,本文总结了超两亲分子的各种类型,包括小分子型、聚合物型和响应性超两亲分子等,以及组装超两亲分子的各种推动力,如主客体相互作用、基于电荷转移作用和不同分子间的协同作用等.研究表明,超两亲分子的研究既可丰富传统的胶体界面化学,又为高级结构的可控组装提供了新的构筑基元,并为制备功能超分子材料开拓了新的途径.     

Studies on the electrochemical and thermodynamic behaviour of Hg-HgS electrode in the presence of sulphide ions

Mercury-mercury (II) sulphide electrode has been prepared and its electrochemical and thermodynamic behaviour has been studied in different media. The electrode is found to show Nernstian response to pS (− log [S²⁻]) over the range 5.19–10.38. In the pH range 7.96–11.98, at constant [S²⁻]_v, its response is also Nernstian. The values of thermodynamic functions, viz., ΔG⁰. ΔH⁰, and ΔS⁰ for the electrode reaction: Hg₍₃)+S²⁻ _aμ ⇌HgS_(s)+2e, have been determined. Further, the standard free energy of formation (ΔG _f ⁰ ) and solubility product constant (K _vp ) of HgS in aqueous medium at 25±0.1°C have also been determined.     

纳米半导体硫化银单层膜的自组装

本文使用Triton X-100作为模板剂制备半导体硫化银纳米颗粒,并研究了其吸收光谱的兰移特性。在金属铝或金基底上自组装有机双功能分子单层膜后,将其浸入所制备的纳米硫化银颗粒的微乳液中,自组装得到硫化银纳米颗粒单层膜并研究了其表面形貌特征。     

Kinetics and Mechanism of the Oxidation of Molybdenum Sulphide

This paper reports on the results attained in the determination of the mechanism of oxidation of molybdenum sulphide under non-isothermal conditions in an air atmosphere. The mechanism of the process was determined by simultaneous DTA-TG-DTG, and the kinetic parameters of the reactions involved were obtained according to the methods of Kissinger and Ozawa. This revised version was published online in July 2006 with corrections to the Cover Date.     

The effect of Thermal History on the Morphology of Nickel sulphide

The DSC characterisation of the morphology of the metastable a phase of stoichiometric nickel sulphide was carried out using two calorimeters; a TA Instruments 2920 MDSC and a Perkin Elmer DSC-7, and two quenching histories. Based on these quenching histories, significant differences were observed in the heat flow curves, including the observation of a second exothermic peak which is tentatively assigned to be a metastable phase to metastable phase transformation. The kinetic constants for the a to b recrystallisation were determined as a function of degree of conversion using a mechanism free isoconversional model. Variations in the values of the kinetic constants were also ascribed to the quenching histories. Although the differences in morphology observed were ascribed to the processing history, the shift in the position of the a to b recrystallisation peak was partially attributed to the thermal resistances of the instruments used. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis,characterization and impregnation of lead sulphide semiconductor nanoparticles on polymer matrix

Lead sulphide nanoparticles were prepared using a precursor and dual sources methods. The composites were fabricated by stabilizing chemically synthesized semiconductor PbS nanocrystals into laurylmethacrylate and ethyleneglycol dimethacrylate matrix in the presence of tri-n-octylphosphine. PbS nanocrystals were dispersed in toluene as a compatible medium for the polymerization and cross-linking of poly laurylmethacrylate networks. The nano-sized particles and polymer composites were characterized by XRD and TEM. Possible formulations and incorporation of these PbS nanoparticles in polymer matrix have been discussed. The reported lead sulphide nanoparticles into tailered polymeric system show greater uniformity and stability.     

Directing the structures of silver-antimony sulphides: A new topological variant of the [Ag5Sb3S8] double layer

A new silver-antimony sulphide, [C₆H₂₀N₄][Ag₅Sb₃S₈], has been synthesised solvothermally in the presence of triethylenetetramine and characterised by single-crystal X-ray diffraction, thermogravimetry and elemental analysis. The compound crystallises in the space group P2₁/m (a=6.2778(7), b=15.8175(16) and and β=104.561(5)°) and adopts a structure in which honeycomb-like sheets of fused six-membered silver-antimony-sulphide rings are linked through Ag-S bonds to form double layers. The idealised structure can be considered to be derived from that of antifluorite and represents a second structure type for the [Ag₅Sb₃S₈]²⁻ double layer.     

硫化钼纳米管的激光真空溅射产生

硫化钼纳米管的激光真空溅射产生张强，黄荣彬，刘朝阳，郑兰荪（厦门大学化学系，固体表面物理化学国家重点实验室，厦门，３６１００５）关键词纳米管，硫化钼，激光溅射自Ｉｉｊｉｍａ［１］发现碳纳米管以来，纳米管的研究一直是功能材料的研究热点．随后的研究发现，...     

Determination of Sulphur in Solid and Liquid Samples by Potentiometric Titration with Ion Selective Electrode.

Abstract

This paper describes a potentiometric method for the determination of sulphur in solid and liquid samples, using a sulphide ion selective electrode after the reduction distillation step. The determination of sulphide in solid and liquid samples without prior treatment was carried out by direct and titration potentiometric methods.

The reproducibility of the method and the recovery of sulphate in solid samples was investigated using analytical reagent grade 99% sodium sulphate. Portions of aproximately 100 mg of reagent were subjected to the reduction distillation process. After the ion selective electrode showed a stable value of the potential, indicating that all the sulphate had been reduced to sulphide, the potentiometric titration with lead nitrate solution was performed. A mean recovery of 98% of sulphate was found. The potentiometric titration method described in this work, can be applied to determine S⁼ in solid samples with the advantage that it does not require sample solubilization or extraction prior to the determination. The method yields an almost total reduction of sulphur and also a good precision.     

Reactions of sulphides in molten cryolite

The freezing point depression of cryolite (Na₃AlF₆) by the addition of Al₂S₃ and FeS was investigated. It was found that for contents of up to 10 wt.% Al₂S₃, it brings into the melt three new species. X-ray analysis of solidified melts of the system Na₃AlF₆–Al₂S₃ showed that it contained chiolite, Na₅Al₃F₁₄ and Na₂S. Chiolite originates from a reaction between Na₃AlF₆ and AlF₃. This suggests that the system Na₃AlF₆–Al₂S₃ is a part of the reciprocal system NaF, AlF₃//Na₂S, Al₂S₃. The solubility of FeS in cryolite melt is so low that it cannot be determined by the thermal analysis. When FeO is added to the Na₃AlF₆–Al₂S₃ melt, Fe²⁺ cations and S²⁻ anions react under the formation of solid FeS. A similar reaction was observed for Ni²⁺ and S²⁻ ions.     

Ultrasensitive determination of silver ion based on synchronous fluorescence spectroscopy with nanoparticles

Based on the characteristics of synchronous fluorescence spectroscopy (SFS), a new method with high sensitivity and selectivity was developed for rapid determination of silver ion with functional cadmium sulphide (CdS) nanoparticles as a fluorescence probe. When Δλ (λ_em − λ_ex) = 215 nm, maximum synchronous fluorescence is produced at 304 nm. Under optimal conditions, functional cadmium sulphide displayed a calibration response for silver ion over a wide concentration range from 0.8 × 10⁻¹⁰ to 1.5 × 10⁻⁸ mol L⁻¹. The limit of detection was 0.4 × 10⁻¹⁰ mol L⁻¹ and the relative standard deviation of seven replicate measurements for the lowest concentration (0.8 × 10⁻¹⁰ mol L⁻¹) was 2.8%. Compared with several fluorescence methods, the proposed method had a wider linear range and improved the sensitivity. Furthermore, the concentration dependence of the synchronous fluorescence intensity is effectively described by a Langmuir-type binding isotherm.