利用分光光度计测量光学元件材料的偏振特性和反射特性

利用进口仪器Ｌａｍｂｄａ－９分光光度所具有的软硬件，在分析研究可调角偏振和高灵敏度反射测量的基础上指出了影响测量精度的有关技术问题，并在不影响仪器原有精度的前提下设计加工了可调角偏振和高灵敏反射测量系统。     

固定化冠醚树脂的特性及离子色谱应用研究 Ⅱ.间接光度检测中苦味酸淋洗剂的一些性质

本文报道用固定化冠醚作色谱填料的无抑制柱间接光度离子色谱法中高灵敏度淋洗剂的性能。苦味酸具有稳定的生色基团和较高的摩尔吸光系数,光学性质良好,是间接光度离子色谱法中优良的淋洗剂。苦味酸浓度以4×10~(-6)mol/L 为最佳。在苦味酸中引入少量甲醇、乙醇、丙酮或氯仿,对提高淋洗剂的灵敏度有利。在苦味酸浓度相同的条件下比较几种填料,其色谱峰高按如下次序递增,固定化二苯并-18-冠-6<固定化二苯并-30-冠-10<固定化苯并-15-冠-5。     

Investigation of shear failure mechanisms of pressure‐sensitive adhesives

We report new experiments investigating the failure mechanisms in shear, of thin layers of acrylic pressure‐sensitive adhesives (PSA). We have developed a novel experimental device able to shear a soft adhesive layer confined between a rigid hemispherical lens and a rigid glass substrate. Using the resources of in situ contact visualization, the nonhomogeneous deformation of the layer and the shear failure processes were observed optically. Depending on the rheological properties of the adhesive, ratios of the contact radius over the layer thickness of 10–30 were achieved, mimicking well the contact conditions encountered in a thin adhesive layer within a joint. When the adhesive was weakly crosslinked, we observed a fluid‐like behavior and could measure a reasonable value for the viscosity of the PSA, implying that flow can occur in the layer and failure will occur by creep. On the other hand, for a more crosslinked adhesive, closer to what is used in applications, a stick‐slip peeling behavior was observed, which involves a coupling between peeling mechanisms at the leading edge of the contact and interfacial slippage. Such a process suggests a failure by fracture rather than by creep. Interestingly, the peeling mechanisms and the associated stress levels change significantly when the layer becomes as thin as 20 μm, implying a fracture process that is controlled by a critical energy release rate in shear G_IIc rather than by a critical shear stress causing failure of the interfacial bonds. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3316–3330, 2005     

水凝胶纳米粒及其在生物医药领域的应用

作为环境响应性和纳米控释给药系统，水凝胶纳米粒主要用于毒副作用大、生物半衰期短、易被生物酶降解的多肽类、蛋白质等生物大分子药物的给药，在生物医药领域具有越来越广阔的应用前景。本文主要综述了水凝胶纳米粒的分类、制备方法及其在生物医药领域的应用。     

Aqueous solution behavior of thermosensitive (N-isopropylacrylamide-acrylic acid-ethyl methacrylate) terpolymers

A series of N-isopropylacrylamide (NIPAM)-acrylic acid–ethyl methacrylate terpolymers with varied monomer compositions was prepared by radical polymerization. The solution behavior of these polymers was studied in dilute aqueous solution using spectrophotometry, fluorescence spectroscopy and high-sensitivity differential scanning calorimetry. The results obtained revealed that the lower critical solution temperatures depend strongly on the copolymer composition, solution pH and ionic strength. At a high pH, the ionization of acrylic acid (AA) units leads to an increase in solution cloud points (T_c). Solutions of polymers containing 10% or less of AA display a constant T_c for pH above 5.5, with 15% there is a continuous increase in T_c with pH and, for higher AA contents, no clouding was observed within the studied temperature range. Fluorescence probe studies were conducted by following the I ₁/I ₃ ratio of pyrene vibronic bands and the emission of anilinonaphtalene sulfonic acid, sodium salt (ANS), both approaches revealing the existence of hydrophobic domains for polymers with higher ethyl methacrylate content at temperatures lower than T_c, suggesting some extent of aggregation and/or a coil-to-globule transition. Scanning calorimetry measurements showed an endothermic transition at temperatures agreeing with the previously detected cloud points. Moreover, the transition curves became broader and with a smaller transition enthalpy, as both the AA content and the solution pH were increased. These broader transitions were interpreted to be the result of a wider molecular distribution upon polymer ionization, hence, displaying varied solution properties. The decrease in transition enthalpy was rationalized as a consequence of reminiscent hydration of NIPAM units, even after phase separation, owing to the presence of electric charges along the polymer chain.     

Use of hydrogen-sensitive Pd-MOS materials in biochemical analysis

A metal oxide semiconductor sensitive to hydrogen was used to monitor H₂ production from immobilizedClostridium acetobutylicum cells and from immobilized hydrogenase on a continuous basis.     

Polymer mediated peptide immobilization onto amino-containing N-isopropylacrylamide-styrene core-shell particles

Monodisperse cationic core-shell latex particles have been prepared using a shot polymerization process, with N-(3-aminopropyl)-methacrylamide-hydrochloride (APMH) as the functional monomer. The final latexes were characterized with respect to final polymerization conversion, water soluble polymer formation, particle size and size distribution, surface charge density and electrokinetic properties. Then the covalent grafting of maleic anhydride-alt-methyl vinyl ether (MAMVE) copolymer onto aminated latex particles was investigated. The most efficient conditions to obtain derivatised particles with no alteration of the colloidal stability were to control both polymer amount/latex particles concentration ratio and the mixing method of the two species. The charge inversion of the hydrolysed MAMVE functionalized particles was demonstrated by measuring the electrophoretic mobility as a function of pH. Finally, the covalent binding approach was implemented with peptide-MAMVE conjugates, confirming the great potential of this promising methodology for the preparation of reactive latex particles bearing peptides.     

超高灵敏显色反应及其应用的研究：Ⅴ.高灵敏光度法测定钼

研究了以Cu~(2 )为催化剂的Mo(V)-SCN~--ERB~ -PVA超高灵敏新显色体系及钼的分光光度测定条件。缔合物的吸收峰在580nm处,表观摩尔吸光系数ε=5.6×10~6L·mol~(-1)·cm~(-1)。Mo(Ⅵ)含量在0～0.3μg/25mL范围内符合比耳定律。初步研讨了显色反应的机理。结合离子交换分离,本法可成功地用于水样及麦饭石浸出液中痕量钼的测定。     

Metallosupramolecular approach toward functional coordination polymers

An appropriate definition of metallosupramolecular coordination polymer is offered, and the relationship between the polymer length, binding constant, and concentration is clarified. The possibility of influencing the binding constant with chelating ligands is discussed on the basis of examples of different Zn²⁺ complexes and their respective binding constants. In the main part, coordination polymers constructed by a supramolecular approach from different metal ions and pyridine–ligand systems are highlighted, and their applications as functional materials for artificial membrane and enzyme models, responsive gels, light‐harvesting systems, and organic light‐emitting diodes are discussed on the basis of individual examples. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4981–4995, 2005     

Temperature-sensitive polyamidoamine dendrimer/poly(N-isopropylacrylamide) hydrogels with improved responsive properties

Novel temperature-sensitive poly(N-isopropylacrylamide)/amine-terminated polyamidoamine dendrimer G6-NH2 hydrogels with fast responsive properties were synthesized by forming semi-interpenetrating polymeric networks. In contrast to the conventional PNIPA hydrogel, these new gels showed rapid shrinking rate at the temperature above lower critical solution temperature (LCST), and exhibited higher equilibrium swelling ratio at room temperature. All these properties might be attributed to the incorporation of polyamidoamine dendrimer G6-NH2, which forms water-releasing channels and increases the hydrophilicity of PNIPA network. The novel hydrogels have potential applications in drug and gene delivery.