NCC负载纳米TiO2复合膜的表征

采用交替沉积自组装的方法制备聚乙烯醇（PVA）/纳米纤维素（NCC）-纳米TiO2/PVA复合膜,用傅里叶变换红外光谱（FT-IR）和扫描电子显微镜（SEM）表征,结果表明PVA/NCC-纳米TiO2/PVA复合膜形貌规整,NCC负载纳米TiO2粒子只是物理共混,没有化学键合.性能分析结果表明PVA/NCC-纳米TiO2/PVA复合膜在紫外光区有较强吸收,较高的拉伸强度109.5 MPa,且比PVA膜热稳定性好,热分解温度提高约20℃.     

Self-Assembled Glucose and Thermo Dual-Responsive Micelles of an Amphiphilic Graft Copolymer

Amphiphilic copolymers P(PBA)-g-P(PEG) containing poly(phenylboronic acid) (PPBA) and poly(ethylene glycol) (PEG) side chains were synthesized by copolymerization of 4-vinylphenylboronic acid (PBA) and poly(ethylene glycol) methyl ether methacrylate. The surface tension results showed that the critical micelle concentration (CMC) of P(PBA)-g-P(PEG) was 0.09 g/L. TEM revealed that these copolymers self-assembled into regular sphere micelles above CMC. The photon correlation spectroscopy suggested that they had unique performance of thermo-induced self-assembly. Above critical micelle temperature, they self-assembled into monodisperse micelles with thermosensitivity. Hydrodynamic diameters of these micelles increased dramatically in the presence of glucose. The glucose-regulated drug release behavior was observed through UV-vis spectroscopy.     

自组装技术在水处理中的应用

介绍了自组装单层及其制备方法，论述了有机硅烷系自组装单层材料可吸附水中金属离子和有机污染物，使水质得到净化，并可用于处理果汁、酒中的有害杂质。采用制备的NH2-SAMs／SiO2处理水中残留的杀虫剂simazine（4mg／L）作为探针反应，去除率达到了76．5％。进一步利用固定在基质上的自组装单层诱导生长TiO2和FeOOH纳米膜作为新型光催化水处理材料，讨论了其吸附、光催化降解水中污染物的方法和应用前景。     

Dynamic self-assembly in living systems as computation

Biochemical reactions taking place in living systems that map different inputs to specific outputs are intuitively recognized as performing information processing. Conventional wisdom distinguishes such proteins, whose primary function is to transfer and process information, from proteins that perform the vast majority of the construction, maintenance, and actuation tasks of the cell (assembling and disassembling macromolecular structures, producing movement, and synthesizing and degrading molecules). In this paper, we examine the computing capabilities of biological processes in the context of the formal model of computing known as the random access machine (RAM) [Dewdney AK (1993) The New Turing Omnibus. Computer Science Press, New York], which is equivalent to a Turing machine [Minsky ML (1967) Computation: Finite and Infinite Machines. Prentice-Hall, Englewood Cliffs, NJ]. When viewed from the RAM perspective, we observe that many of these dynamic self-assembly processes – synthesis, degradation, assembly, movement – do carry out computational operations. We also show that the same computing model is applicable at other hierarchical levels of biological systems (e.g., cellular or organism networks as well as molecular networks). We present stochastic simulations of idealized protein networks designed explicitly to carry out a numeric calculation. We explore the reliability of such computations and discuss error-correction strategies (algorithms) employed by living systems. Finally, we discuss some real examples of dynamic self-assembly processes that occur in living systems, and describe the RAM computer programs they implement. Thus, by viewing the processes of living systems from the RAM perspective, a far greater fraction of these processes can be understood as computing than has been previously recognized.     

Gold Nanoparticulate Thin Films Fabricated by the Electrostatic Self—Assembly Process

Gold colloids were prepared by citrate-induced reduction of hydrogen tetrachlorourate, and gold nanoparticles were electrostatically self-assembled with poly (diallyldimethylammonium chloride) into multilayer thin films on silicon and quartz substrates. The particulate thin films were characterized by UV-vis spectroscopy, surface enhanced Raman scattering, atomic force microscopy and resistivity measurements. Due to the interparticle coupling between individual gold particles, an obvious collective particle plasmon resonance was observed on UV-vis spectra, and the particulate thin films exhibited a strong SERS effect. For multilayer thin films with a high particle coverage on substrates, resistivity of the order of 10⁻⁴Ω·cm was yielded. Yu Hai-hu This research was financially supported by China Scholarship Council and the Natural Science Foundation of Hubei Province (Project 2000J002)     

对称性分子间氢键诱导液晶

本文以４－［（４－烷氧基苯甲酰氧基）－４’－苯乙烯基］－吡啶（７ＳＺ和１０ＳＺ）为质子受体．以脂肪族二元羧酸（ｍＤＡ）为质子给体，合成了对称性的氢键复和物。其液晶行为经ＤＳＣ和偏光显微镜研究，结果表明复合物的液晶范围较相应的质子受体的液晶范围宽．     

Study on synthesis of glycopeptide-based triblock copolymers and their aggregation behavior in water

This paper describes a preliminary study on the synthesis of glycopeptide-based triblock copolymers and their aggregate behavior in water. Initially, a polypeptide-based triblock copolymer, poly(L-lysine)-b-poly(tetrahydrofuran)-b-poly(L-lysine) (PLL₃₀-b-PTHF-b-PLL₃₀), was synthesized by the ring-opening polymerization of ɛ-benzyloxycarbonyl-L-lysine N-carboxyanhydride using amine-terminated poly(tetrahydrofuran) as a macroinitiator in the fixed feed ratio, followed by the removal of the protecting group. The resulting copolymer then reacted with a varying amount of D-gluconolactone in the presence of dipropylethylamine to give the corresponding glycopeptide-based copolymers with high yields. This kind of amphiphilic sugar-containing triblock copolymer can self-assemble into nano-sized aggregates in water. The critical aggregation concentration (CAC) was determined in the range of around 10⁻⁶ M by fluorescence measurement. The spherical morphologies in 100–150 nm scale were also evidenced by transmission electron microscopy (TEM) measurements. They show potential as carriers for drug controlled delivery and templates for biomimetic mineralization.     

花状纳米金属及金属化合物的合成及其电磁性能研究

三维花状结构的纳米金属及金属化合物材料作为纳米材料的一个重要组成部分,由于其特殊的形貌和复杂的结构而具备许多块状或者低维纳米材料不具备的性质,在光、电、磁、催化和传感方面显示出巨大的应用前景.综述了近年来有关花状结构纳米金属及金属化合物的合成、性能及其应用,分别介绍了花状纳米金属及金属化合物的主要合成方法,阐述了各种花状纳米金属及金属化合物的电磁性质及其在相关领域的应用.     

Electrostatic self-assembly of Pt nanoparticles on hexagonal tungsten oxide as an active CO-tolerant hydrogen oxidation electrocatalyst

Developing CO-tolerant electrocatalysts is of great importance for the practical use of proton exchange membrane fuel cells (PEMFCs) fed with reforming hydrogen. Transitional metal oxides are a class of promising component to (i) alleviate the CO adsorption on Pt and (ii) provide as a stabilized support for Pt nanoparticles. Herein, we developed an electrostatic assembly strategy to deposit Pt nanoparticles uniformly on the hexagonal tungsten oxides (hex-WO₃) modified by polyethleneimine (PEI). It is the first time employing hex-WO₃ with biomimetic proton channels and mixed ionic electronic conductivity as supports in PEMFCs. Also, this work is the first report using PEI as a linker to assemble Pt nanoparticles and metal oxide supports. The Pt/PEI-hex-WO₃ composites possess excellent dispersion of Pt nanoparticles with average size less than 3 nm even at Pt loadings as high as 40 wt%. The Pt/PEI-hex-WO₃ catalysts exhibit superior catalytic activity and electrochemical stability for the hydrogen electro-oxidation (HOR) in the presence of CO, and good PEMFC performance compared to the conventional carbon-supported Pt catalysts, attributed to the bifunctional mechanism and a strong metal-support interaction (SMSI).     

Investigation on carbon nanotube oxide for anhydrous proton exchange membranes application

The widespread participation of polymers in the membrane preparation has been considering to be critical for the development of proton exchange membranes (PEMs). For the polymers without functional groups to conduct protons, the introduction of proton conduction carriers with the formation of composite membranes is an effective strategy to prepare PEMs with the outstanding proton conductivity. However, there remains a potential risk of the components leaking from composite membranes due to the lack of the interaction force. Here, the composite of carbon nanotube oxide (OCNT) assembling with cadmium telluride (CdTe) and 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF₆) was introduced into the system of phosphoric acid (PA) doping poly(vinylidene fluoride) (PVDF) with the formation of PVDF/OCNT-CdTe-bmimPF₆/85%PA membranes. PA molecules are anchored by the inorganics of OCNT-CdTe-bmimPF₆ and are stabilized in membranes. The high and stable proton conductivity values at the elevated temperature are obtained comparing the reported PVDF/bmimPF₆/PA membranes. Specifically, the proton conductivity value reached 1.28 × 10⁻¹ S/cm at 160 °C and the value is stable 1.70 × 10⁻² S/cm at 120 °C lasting for 350 h. The fine stability in components could make the membranes extricate from the predicament of proton conductivity decline exceeding 120 °C under anhydrous conditions in PVDF/bmimPF₆/PA membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48833.