In situ gamma ray-initiated polymerization to stabilize surface micelles

Surfactant molecules containing hydrophobic long alkyl chains and hydrophilic groups can organize into various micellar structures both in bulk solution and at interface. However, because of the dynamical nature of surfactant micelles, efforts directed at fixing their structures in bulk solution by polymerization have met with limited success. Herein, we report a unique and simple method of stabilizing surface micelles of a low molecular weight surfactant 11-acryloyloxyundecyltriethylammonium bromide (AUTEAB) through in situ intramicellar polymerization on the mica surface. Atomic force microscopy (AFM) observations show that the cylindrical micellar structure formed by AUTEAB monomers at the mica/water interface is preserved after the in situ polymerization, and the stability of the polymerized surface micelles is greatly enhanced compared with that of the unpolymerized ones.     

Determination of sophoridine and related lupin alkaloids using tris(2,2′-bipyridine)ruthenium electrogenerated chemiluminescence

Electrogenerated chemiluminescences (ECLs) based on tris(2,2′-bipyridine)ruthenium(II) (Ru(bpy)₃²⁺) and lupin alkaloids, for instance, sophoridine (SRI), matrine (MT), sophoranol (SR) and sophocarpine (SC) in an aqueous alkaline buffer solution (pH 9.0) are studied. The light emission is mainly caused by an electro-oxidation reaction between tertiary amino group on the alkaloid compounds and Ru(bpy)₃²⁺ in a thin layer flow cell equipped with a glassy carbon disc electrode (22.1 mm²) at the potential of +1.50 V (versus Ag/AgCl). The luminescence wavelength of 610 nm confirmed that ECL is caused by Ru(bpy)₃^2+∗ to its ground state. ECL intensities of these lupin alkaloids are affected by the substituent character, three-dimensional conformation of hydrogen on β-carbon atom. Ionization potentials taken from calculation data further confirm the experimental results. In addition, the factors affecting the determination and HPLC separation of the four alkaloids are also investigated.     

Efficient Synthesis of p-Hydroxyphenyl Ethanol from Hydrogenation of Methyl p-Hydroxyphenylacetate with CNTs-promoted Cu-Zr Catalyst

Hydrogenation of methyl p-hydroxyphenylacetate has been used for the synthesis of p-hydroxyphenyl ethanol. The reaction was catalyzed by Cu_iZr_j-x%(mass fraction) carbon nanotubes(CNTs) catalysts. Incorporation of a minor amount of CNTs into Cu_iZr_j oxide can visibly increase the catalytic activity for the synthesis of p-hydroxyphenyl ethanol. The yield of p-hydroxyphenyl ethanol reaches 94.2% over a co-precipitated catalyst of Cu₃Zr₁ oxide with 11.0%CNTs. Its catalytic activity shows no obvious decrease after three cycles. This is much better than the CNT-free co-precipitated catalyst with a good yield of 81.1%, Cu₃Zr₁-0%CNTs.     

A Generalized Blow up Criteria with One Component of Velocity for 3D Incompressible MHD System∗

In this paper, the authors study the global regularity of the 3D magnetohydrodynamics system in terms of one velocity component. In particular, they establish a new Prodi-Serrin type regularity criterion in the framework of weak Lebesgue spaces both in time and space variables.     

Partial P-Type Metal Ions Doping Induced Variation of Both Crystal Structure and Oxygen Vacancy Within Cu/SnO2 Metastable Solid Solution Nanofibers for Highly Sensitive C2H2 Sensor

Partial P-type metal ions doping(PPMID) is an alternative method to further enhance the gas sensing performance of N-type metal oxides(NMOs) in contrast to that of P-N metal oxides heterojunctions, but the influences of the introduction of PPMID on the grain size and oxygen vacancies of NMOs have been rarely investigated. Herein, a simple and effective route has been demonstrated to address this problem with Cu²⁺-doped SnO₂ metastable solid solution nanofibers(CSMSSNs) as model and C₂H₂ as target molecule by combining electrospinning and calcination technique. It seems that the introduction of PPMID can also affect crystal structure and oxygen vacancies of NMOs, proven by combining X-ray diffraction(XRD) and X-ray photoelectron spectra(XPS). Thus, PPD, crystal structure and oxygen vacancies have been combined to clarify the enhanced sensing performance of Cu-doped SnO₂ metastable solid solution nanofibers angainst C₂H₂.     

Insight into the reaction mechanism of sulfur chains adjustable polymer cathode for high-loading lithium-organosulfur batteries

Small molecules with adjustable sulfur atoms in the confined structure were acted as precursor for the synthesis of polymer cathodes for lithium-organosulfur batteries.Among them,poly(diallyl tetrasulfide)(PDATtS)delivered a high capacity of 700 mAh g^-1,stable capacity retention of 85%after 300 cycles,high areal capacity~4 m Ah cm^-2 for electrode with up to 10.3 mg cm^-2 loading.New insight into the reaction mechanism of PDATtS electrode that radicals arisen from the homolytic cleavage of S-S bond in PDATtS reacted with Li+to generate thiolates(RSLi)and insoluble lithium sulfides(Li₂S)or lithium disulfide(Li₂S₂)was clearly verified by in-situ UV/Vis spectroscopy,nuclear magnetic resonance(NMR)studies and density-functional theory(DFT)calculations.Therefore,based on the unique reaction mechanism,problems of rapid capacity fading due to the formation of soluble polysulfide intermediates and their serious shuttle effect in conventional lithium-sulfur(Li-S)batteries was totally avoided,realizing the dendrite-free lithium sulfur batteries.This study sets new trends for avenues of further research to advance Li-S battery technologies.     

缓冲层ZnPc对有机电致发光器件特性的影响

本文研究了酞菁锌(ZnPc)薄膜的表面形貌及ZnPc薄膜作为缓冲层对有机电致发光器件(OLEDs)光电特性的影响.对比两组样品的AFM图像,ZnPc薄膜相比于ITO薄膜,其表面的岛面积较大,薄膜表面更连续平整,基本上覆盖了ITO膜表面针孔,减少了表面的缺陷.另外,ZnPc薄膜的岛分布均匀有序.使用ZnPc作为缓冲层的器件性能明显好于未使用ZnPc修饰的器件,在7.42V的驱动电压下的最大发光亮度达到1.428kcd/m2,在4.3V电压驱动下时,最大光功率效率为1.411m/W;而未使用缓冲层的器件在8V的驱动电压下达到最大发光亮度达到1.212kcd/m2,在5.5V电压驱动下时,最大光功率效率为0.931m/W.