Sep 2010, Volume 5 Issue 3
    

  • Select all
  • Research articles
    Bioinspired synthesis and preparation of multilevel micro/nanostructured materials
    Nü WANG, Yong ZHAO, Lei JIANG,
    2010, 5(3): 247-261. https://doi.org/10.1007/s11458-010-0002-2
    Download PDF
    In this review, some living organisms with multilevel hierarchical micro/nanostructures and related special properties are briefly introduced. The unique properties of organisms are mostly related to their special hierarchical micro/nanostructures. Inspired by nature, many zero-dimensional and one-dimensional micro/nanomaterials with biomimic or bioinspired multilevel micro/nanostructures have been successfully synthesized and prepared in recent years. Compared with traditional solid materials, the synthesis and preparation of these multilevel structured materials is more ingenious. Moreover, these kinds of multilevel micro/nanomaterials show fantastic properties in many fields because of their micro/nanoscale complex interior structures, which may be intended for application in catalysis, Li-ion batteries, biomedicines, sensors, and others.
  • Research articles
    The crystallization and morphology of melt-miscible polymer blends
    Jerold. M. SCHULTZ,
    2010, 5(3): 262-276. https://doi.org/10.1007/s11458-010-0211-8
    Download PDF
    The morphology and kinetics of crystallization from melt-miscible blends is reviewed for binary systems in which either one or both polymer components are crystallizable. In systems in which one component (component A) crystallizes first, the other component (B) may reside finally between spherulites, between growth arms (composed of a stack of A crystalline lamellae), or between crystal lamellae of A. The kinetics of component redistribution dictates which site must become primary. It is shown that the diffusivity D of the components in the melt and the velocity V of spherulite growth combine through the diffusion length d = D/V to define the final location for component B and to also define whether spherulite propagation will be linear or parabolic in time. When crystallization of both components proceeds concurrently, by forming spherulites of A and of B, the spherulites are prone to interpenetrate or to form concentric spherulites. Cooperative crystallization, in which the kinetics of a rapidly crystallizing component and a slowly crystallizing component are both affected such that the two crystallize nearly simultaneously, is discussed. Finally, the competition between liquid-liquid phase separation and crystallization in systems with either an upper or lower critical solution temperature is reviewed.
  • Research articles
    Self-assembly of bridged silsesquioxanes incorporated with conjugated organic functionalities
    Li LI, Fangjing CAI, Xuemei SUN, Huisheng PENG,
    2010, 5(3): 277-287. https://doi.org/10.1007/s11458-010-0213-6
    Download PDF
    Self-assembly of bridged silsesquioxanes with a chemical structure of (RO)3Si-R′-Si(OR)3 represents an efficient approach to design and to fabricate functional organic/inorganic nanocomposites. The desired functionalities are mainly incorporated into the R’ with R of a hydrolysable alkoxide group such as CH3 or CH3CH2. This feature article discusses two typical assembly approaches: self-directed assembly aiming at ordered solid materials and surfactant-directed assembly aiming at periodic mesoporous organosilica, with emphasis on the bridged silsesquioxanes in which conjugated functional organic groups are incorporated. The conjugated moieties are shown to be critical to the resulting assembly structure, morphology, and property. Self-assembly of three bridged silsesquioxanes based on polydiacetylene, perylene, and porphyrin has been detailed, respectively.
  • Research articles
    Dissipative particle dynamic simulation study of lipid membrane
    Shaogui WU, Teng LU, Hongxia GUO,
    2010, 5(3): 288-298. https://doi.org/10.1007/s11458-009-0210-9
    Download PDF
    The lipid membrane plays crucial roles in countless biologic processes, ranging from cell motility, endo- and exocytosis, and cell division to protein aggregation and trafficking. To gain a molecular insight in these biologic processes, the recently developed mesoscale simulation technique, dissipative particle dynamics (DPD) simulation, has become an invaluable tool. By providing a brief survey of existing atomistic and popular coarse-grained models used today in studying the dynamics (including vesicle formation and (protein-mediated) vesicle fusion) and phase behavior of lipid bilayers, this review illustrates how mesoscopic DPD models can be used to obtain a better understanding of these biologic processes currently inaccessible to atomistic and most coarse-grained models.
  • Research articles
    Biomineralization of sea urchin teeth
    Yurong MA, Limin QI,
    2010, 5(3): 299-308. https://doi.org/10.1007/s11458-010-0215-4
    Download PDF
    The sea urchin tooth, which is composed almost entirely of Mg-enriched CaCO3, is of particular interest as a model for the study of biomineralization process due to its amazing mechanical toughness and hardness. Our recent work on the formation process, the crystal composition and orientation, and the mechanical properties of sea urchin tooth are summarized in this paper. First, transmission electron microscopy images and electron diffraction patterns, as well as crystal overgrowth experiments, show that the highly convoluted primary plate-lamellar needle complex grows into a single crystal of calcite from a transient amorphous precursor phase in the sea urchin tooth. Amorphous calcium carbonate exists in the center of both the primary plates and the needles, even though the surfaces are already well crystallized. Second, X-ray photoelectron emission spectromicroscopy demonstrates that the needles, primary plates, and polycrystalline matrix crystals are all aligned. And there are two alternating crystal orientations in the stone part of the sea urchin tooth. Microbeam X-ray diffraction patterns further prove the existence of the two crystal orientations in sea urchin tooth. The c axes of calcite in the two oriented crystals are only a few degrees from each other. Third, the mechanical properties of sea urchin tooth grinding tip were studied by nanoindentation. The polycrystalline matrix has a higher elastic modulus and hardness than single crystalline needles and plates. It is proposed that the grinding capability of the tooth can be attributed to the small and uniform sizes of the polycrystalline crystals, their high Mg contents, and the two co-orientations of single crystals and polycrystalline structure. The improved understanding of the biomineralization process of sea urchin tooth and the relations between their structures and mechanical properties may shed light on the design of mechanical grinding and cutting tools with tunable properties.
  • Research articles
    Peptides-assisted charge transfers in proteins: relay mechanism and its controllability
    Yuxiang BU,
    2010, 5(3): 309-324. https://doi.org/10.1007/s11458-010-0217-2
    Download PDF
    This feature article addresses several novel aspects regarding the peptide-mediated charge migrations, including: i) radical exchanges with tunable radical types (σ-radical versus π-radical) and electron-transfer (ET)-channel-tunable cooperative proton-coupled ET (PCET) mechanism, including hydrogen-atom transfer (HAT), single ET-channel PCET, double ET channel PCET, and channel-type-tunable (σ-channel versus π-channel) PCET; ii) hole hopping migration between the active groups in the side-chains and its controllability; iii) hole hopping through stepping-stones via a solvated “hole” form; and iv) electron hopping through positively charged groups as stepping-stones via a solvated electron state. In particular, the controllability of the ET channels (pathways and types) and solvated-“hole”/“electron”-based relay mechanisms are mainly mentioned. Clearly, this is an important addition to the well-documented mechanisms for charge migration in proteins. In view of the complexity of protein charge migration, further exploration on details of the stepping-stone-based relay mechanisms, by considering the properties and structures of the redox active centers, their intercalators, and the real surroundings, is still needed.
  • Research articles
    Sterol-containing tetraphenylethenes: synthesis, aggregation-induced emission, and organogel formation
    Yang LIU, Jacky W. Y. LAM, Faisal MAHTAB, Ryan T. K. KWOK, Ben Zhong TANG,
    2010, 5(3): 325-330. https://doi.org/10.1007/s11458-010-0212-7
    Download PDF
    Cholesterol- and stigmasterol-containing tetraphenylethenes (TPEs) (TPE-Chol and TPE-Stig) are facilely synthesized in satisfactory yields by Cu (I)-catalyzed click reaction of 1,2-bis(4-azidomethylphenyl)-1,2-diphenylethene and cholesteryl-4-ethylbenoate and sigmasteryl 11-(4-ethynylphenoxy)undecanoate, respectively. Whereas they are nonluminescent in solution, they become highly emissive when aggregated in the condensed phase. The molecules of TPE-Stig can self-assemble in methanol solution, generating organogels with gelation-induced emission characteristics.
  • Research articles
    Real-time, single-particle measurements of ambient aerosols in Shanghai
    Fan YANG, Xinning WANG, Yaping ZHANG, Xiaofei WANG, Hong CHEN, Xin YANG, Jianmin CHEN,
    2010, 5(3): 331-341. https://doi.org/10.1007/s11458-010-0004-0
    Download PDF
    As one of the major components of the earth’s atmosphere, airborne particulate matter (or aerosol) has strong effects on air quality, regional and global climate, and human health. In ambient atmosphere, the different sources and complex evolutionary history of aerosol particles make the study of their chemical and physical properties extremely challenging. The invention of an online single-particle aerosol mass spectrometer provides a powerful technique to determine the size and chemical composition of individual aerosol particles in real time. We deployed an aerosol time-of-flight mass spectrometer (ATOFMS) to carry out single particle measurement in the urban area of Shanghai in the past few years. In this review paper, we summarize our recent work on the identification of particle type, mixing state and aging process, and the application of the individual particle information to the source apportionment of primary aerosol, and the investigation of the formation mechanism of secondary aerosol in Shanghai. The special capabilities of single particle mass spectrometry are proven essential to these studies. Multi-functional technique combinations of ATOFMS with other state-of-art aerosol instruments are also discussed for future studies.
  • Research articles
    Synthesis and characterization of a novel well-defined comb-like ionomer
    Zijian LV, Aixiang LI, Zaijun LU,
    2010, 5(3): 342-347. https://doi.org/10.1007/s11458-010-0218-1
    Download PDF
    A novel well-defined comb-like ionomer with cations was synthesized by the combination of living anionic polymerization and atom transfer radical polymerization (ATRP). The synthetic approach involves the coupling reaction of polystyrene (PS) backbone bearing 1,1-diphenylethene (DPE) pendant groups with living polystyryllithium (PSLi), subsequent amine functionalization of the resulting 1,1-diphenylmethyl anions with 3-dimethylaminopropyl chloride (DMAPC), and quaternization of tertiary amino groups with hydrochloric acid. The comb-like ionomer was characterized by 1H NMR, IR, GPC measurements and end-group titrition.
  • Research articles
    Synthesis and biological studies of complexes of 2-amino- N (2-aminobenzoyl)benzohydrazide with Co(II), Ni(II), and Cu(II)
    Saeed-Ur- Rehman, Muhammad Ikram, Sadia Rehman,
    2010, 5(3): 348-356. https://doi.org/10.1007/s11458-010-0216-3
    Download PDF
    The present work is concerned with the synthesis and coordination compounds of 2-amino-N(2-aminobezoyl)benzohydrazide (ABH). The ligand was synthesized by the reaction of methylanthranilate and hydrazine in 2:1 molar ratio. It can be viewed as a modified form of hydrazide. The ligand was characterized by 1H-NMR, 13C-NMR, mass spectrometry, elemental analysis, and infrared studies. The ligand has got –NH2 moeity, the site for chelation. The complexes of Co(II), Ni(II), and Cu(II) chlorides and bromides were prepared. These complexes were characterized by elemental analysis, infrared, conductance, and magnetic susceptibility studies. Infrared spectra studies confirmed the formation of complexes, while elemental studies suggested the complexation of [M(ABH)X2] (where X= Cl− or Br−) composition.
    Knowing about the importance of –N–N– linkage in the biologically active compounds, the synthesized complexes were studied for their biological activity, and were found to be potentially strong in inhibition activity as compared to the neat ligand.