The Experts below are selected from a list of 120885 Experts worldwide ranked by ideXlab platform

Zhongyi Jiang - One of the best experts on this subject based on the ideXlab platform.

  • molecular simulation on penetrants Diffusion at the interface region of organic inorganic hybrid membranes
    Chemical Engineering Science, 2008
    Co-Authors: Fusheng Pan, Fubing Peng, Jingtao Wang, Zhongyi Jiang
    Abstract:

    Abstract Detailed atomistic structures of blend (class I) and chemical tethered (class II) poly vinyl alcohol (PVA)–silica hybrid membranes were constructed to investigate the Diffusion Behavior of small molecules at the interfacial region. Stronger interaction between PVA and silica, as well as more appropriate interfacial morphology which was evaluated by interchain distance, chain mobility and free volume were found in class II hybrid membranes due to the presence of covalent bonds. The effects of interfacial morphology on Diffusion Behavior of small molecules including benzene and cyclohexane were tentatively explored, and found that Diffusion coefficients were closely related to fraction of free volume (FFV). Subsequently, the Diffusion selectivity was calculated by the ratio of FFV probed by benzene and cyclohexane molecules. Hopefully, this study will offer some important qualitative insight into the transport phenomena within organic–inorganic hybrid membranes.

  • Diffusion Behavior of benzene cyclohexane molecules in poly vinyl alcohol graphite hybrid membranes by molecular dynamics simulation
    Chemical Engineering Science, 2007
    Co-Authors: Fusheng Pan, Fubing Peng, Zhongyi Jiang
    Abstract:

    Abstract Understanding the effects of incorporated inorganic particles in organic–inorganic hybrid membranes at molecular level is crucial to design hybrid membranes with tailored structure and desired properties. In this study, molecular dynamics simulation has been employed to investigate the effects of graphite particle on the Diffusion Behavior of benzene and cyclohexane in poly(vinyl alcohol)-graphite hybrid membranes. Firstly, the non-bonding interaction energies between PVA polymer and graphite particle with different amount of hydroxyl and carboxyl groups were calculated by DREIDING force field. Next, polymer chain mobility was analyzed by mean-square displacement (MSD) and glass transition temperature ( T g ) , and found that incorporation of graphite particle into PVA increased the polymer chain mobility. Free volume characteristics of membranes were investigated by Connolly surface, and found that free volumes in PVA-graphite hybrid membranes were larger than those in PVA control membranes. This simulation result showed the same tendency with the PALS measurement. Finally, the Diffusion coefficients of benzene and cyclohexane in the membranes were calculated by Einstein relation, and found that the Diffusion coefficients in hybrid membranes were larger than those in the control membrane. Furthermore, it was found that the Diffusion coefficients of benzene and cyclohexane in the membranes exhibited exponential relation with the inverse fractional free volumes and agreed well with the free volume theory.

Cheng Zhang - One of the best experts on this subject based on the ideXlab platform.

  • fast switching properties and ion Diffusion Behavior of polytriphenylamine derivative with pendent ionic liquid unit
    ACS Applied Materials & Interfaces, 2018
    Co-Authors: Liang Qian, Mi Ouyang, Alexey Tameev, Konstantin Katin, Conghui Huang, Rui Zhu, Mikhail M Maslov, Cheng Zhang
    Abstract:

    A novel triphenylamine derivative-linked ionic liquid unit, 1-(6-((4-(bis(4-(thiophen-2-yl)phenyl)amino)benzoyl)oxy)hexyl)-3-methyl-imidazolium tetrafluoroborate (TTPAC6IL-BF4), was designed and synthesized successfully, and its corresponding polymer PTTPAC6IL-BF4 was obtained by the electropolymerization method. The highest occupied molecular orbital energy band of TTPAC6IL-BF4 is higher and the onset oxidative potential lower compared with that of 6-bromohexyl 4-(bis(4-(thiophen-2-yl)phenyl)amino) benzoate (TTPAC6Br) without modifying the ionic liquid unit. Both PTTPAC6IL-BF4 and PTTPAC6Br show similar color change and optical contrast under different redox states. However, PTTPAC6IL-BF4 presents a faster electrochromic switching time than PTTPAC6Br owing to the improved ionic conductivity and ion Diffusion coefficient with the introduction of a pendent ionic liquid unit. It is more intriguing that PTTPAC6IL-BF4 could show electrochromism under different potentials even without supplying any additional ...

  • Fast Switching Properties and Ion Diffusion Behavior of Polytriphenylamine Derivative with Pendent Ionic Liquid Unit
    2018
    Co-Authors: Liang Qian, Mi Ouyang, Alexey Tameev, Konstantin Katin, Mikhail Maslov, Conghui Huang, Rui Zhu, Cheng Zhang
    Abstract:

    A novel triphenylamine derivative-linked ionic liquid unit, 1-(6-((4-(bis­(4-(thiophen-2-yl)­phenyl)­amino)­benzoyl)­oxy)­hexyl)-3-methyl-imidazolium tetrafluoroborate (TTPAC6IL-BF4), was designed and synthesized successfully, and its corresponding polymer PTTPAC6IL-BF4 was obtained by the electropolymerization method. The highest occupied molecular orbital energy band of TTPAC6IL-BF4 is higher and the onset oxidative potential lower compared with that of 6-bromohexyl 4-(bis­(4-(thiophen-2-yl)­phenyl)­amino) benzoate (TTPAC6Br) without modifying the ionic liquid unit. Both PTTPAC6IL-BF4 and PTTPAC6Br show similar color change and optical contrast under different redox states. However, PTTPAC6IL-BF4 presents a faster electrochromic switching time than PTTPAC6Br owing to the improved ionic conductivity and ion Diffusion coefficient with the introduction of a pendent ionic liquid unit. It is more intriguing that PTTPAC6IL-BF4 could show electrochromism under different potentials even without supplying any additional electrolyte. The particular Behavior further proves that BF4– ions around imidazole cations at the side chain may participate in balancing the charge of the polymer backbone when redox reaction happens, resulting in faster movement of ions during the doping process. The results imply that introducing an ionic liquid unit to the side chain is an efficient method to improve the switching time of conjugated polymers and would be inspirational for the design and preparation of novel bifunctional electrochromic polymeric electrolytes

Simone Wiegand - One of the best experts on this subject based on the ideXlab platform.

  • study of the soret effect in monosaccharide solutions
    Journal of Physical Chemistry B, 2010
    Co-Authors: Pablo Blanco, Simone Wiegand
    Abstract:

    We investigated the thermal Diffusion Behavior of aqueous solutions of monosaccharides with the infrared thermal Diffusion forced Rayleigh scattering (IR-TDFRS) setup. As monosaccharides, we studied the three aldohexoses glucose, galactose, and mannose and the two ketohexoses sorbose and fructose. All sugars have the same molecular weight, but their structures differ as well as some physical properties such as viscosity, density, thermal expansion coefficient, and optical rotation. Additionally, we measured the viscosity and the optical rotation of the monosaccharide solutions in the investigated temperature and concentration range. While there is a clear correlation between the structure and the thermal Diffusion Behavior for alkanes, the situation is much more complicated for the monosaccharides. Nevertheless, as in the case of the alkanes, we find a correlation between the thermal Diffusion coefficient with the ratio of the thermal expansion coefficient and the kinematic viscosity. We discuss the physi...

  • reverse nonequilibrium molecular dynamics calculation of the soret coefficient in liquid heptane benzene mixtures
    Journal of Physical Chemistry B, 2008
    Co-Authors: Pavel Polyakov, Florian Mullerplathe, Simone Wiegand
    Abstract:

    We studied the thermal Diffusion Behavior of mixtures of benzene and heptane isomers by reverse nonequilibrium molecular dynamics. For n-heptane/benzene mixtures, we investigated the concentration dependence of the Soret coefficient. The Soret coefficient for equimolar mixtures of the three heptane isomers 3-methylhexane, 2,3-dimethylpentane, and 2,4-dimethylpentane in benzene has been calculated. Compared to the experimental data, the simulation results show the same trend in dependence of the mole fraction and degree of branching. The negative Soret coefficient indicates the enrichment of alkanes in the warm side. In the case of the heptane isomers in benzene, we could study the influence of the difference in shape and size on the thermal Diffusion Behavior at constant mass. In the simulation as well as in the experiment, we found that the Soret coefficients become higher with increasing degree of branching. Such Behavior cannot be explained only by mass and size effects. The effect of the molecular sha...

Sergey Vasenkov - One of the best experts on this subject based on the ideXlab platform.

  • influence of water on Diffusion in imidazolium based ionic liquids a pulsed field gradient nmr study
    Journal of Physical Chemistry B, 2009
    Co-Authors: Amrish Menjoge, Janeille K Dixon, Joan F Brennecke, Edward J Maginn, Sergey Vasenkov
    Abstract:

    In this work, we applied a novel pulsed field gradient (PFG) NMR option, which combines advantages of high-field (17.6 T) NMR and high magnetic field gradients (up to 30 T/m), to study Diffusion of anions, cations and water in two 1-ethyl-3-methylimidazolium-based ionic liquids. Application of high field allows for an easy recording of an NMR signal from small amounts of water added to the ionic liquids. Using high gradients is advantageous because under conditions of such gradients any susceptibility-induced inhomogeneities in the local magnetic field are expected to be negligibly small in comparison with the applied gradients. PFG NMR studies have been performed in a broad range of temperatures and for different Diffusion times. The effect of water addition on the Diffusion Behavior of the anions and cations is discussed in the context of the presence of polar and nonpolar domains in the ionic liquids. A partial screening of the electrostatic interaction between the cations and anions in the polar domains by water is believed to be responsible for the following changes in the Diffusion Behavior, which were observed experimentally: (i) increase in the ion diffusivities with increasing water concentration, and (ii) decrease in the difference between the Diffusion coefficient of the cation and that of the anion as water concentration increases.

Shaotong Jiang - One of the best experts on this subject based on the ideXlab platform.

  • functional effectiveness and Diffusion Behavior of sodium lactate loaded chitosan poly l lactic acid film with antimicrobial activity
    RSC Advances, 2015
    Co-Authors: Hualin Wang, Ru Zhang, Junfeng Cheng, Huan Liu, Linfeng Zhai, Shaotong Jiang
    Abstract:

    The present work aimed to evaluate the functional effectiveness and Diffusion Behavior of sodium lactate loaded chitosan/poly(L-lactic acid) (SL-CS/PLLA) film prepared by coating method as a novel active packaging, using Escherichia coli (E. coli, 8099) as test bacterium. The hydrogen bonds formed between CS and PLLA improved the thermal stability and caused a decrease in crystalline of the composite film. The incorporation of PLLA increased the hydrophobicity of film and resulted in a decrease in water gain percentage at equilibrium with decreasing CS/PLLA ratio. The PLLA was valid in blocking visible light and invalid in blocking ultraviolet light through films, and the surface color of CS/PLLA films changed distinctively as compared to neat CS film. The decrease of CS/PLLA ratio caused a decrease in both water vapor permeability (WVP) and oxygen permeability (OP), which reached their minimum values at 1.95 × 10−3 g m−1 d−1 kPa−1 and 2.1 × 10−3 cm2 d−1 kPa−1 for CS/PLLA ratio at 1:1, respectively. The SL-CS/PLLA film displayed well controlled release and the initial Diffusion of SL (Mt/M∞ < 2/3) could be well described by Fickian Diffusion equation. The thermodynamic parameters suggested that the Diffusion of SL was endothermic and spontaneous, and the increase of temperature and PLLA content in film favored the Diffusion of SL.

  • functional effectiveness and Diffusion Behavior of sodium lactate loaded chitosan poly l lactic acid film with antimicrobial activity
    RSC Advances, 2015
    Co-Authors: Hualin Wang, Ru Zhang, Junfeng Cheng, Linfeng Zhai, Shaotong Jiang
    Abstract:

    The present work aimed to evaluate the functional effectiveness and Diffusion Behavior of sodium lactate loaded chitosan/poly(L-lactic acid) (SL-CS/PLLA) film prepared by coating method as a novel active packaging, using Escherichia coli (E. coli, 8099) as test bacterium. The hydrogen bonds formed between CS and PLLA improved the thermal stability and caused a decrease in crystalline of the composite film. The incorporation of PLLA increased the hydrophobicity of film and resulted in a decrease in water gain percentage at equilibrium with decreasing CS/PLLA ratio. The PLLA was valid in blocking visible light and invalid in blocking ultraviolet light through films, and the surface color of CS/PLLA films changed distinctively as compared to neat CS film. The decrease of CS/PLLA ratio caused a decrease in both water vapor permeability (WVP) and oxygen permeability (OP), which reached their minimum values at 1.95 × 10−3 g m−1 d−1 kPa−1 and 2.1 × 10−3 cm2 d−1 kPa−1 for CS/PLLA ratio at 1:1, respectively. The SL-CS/PLLA film displayed well controlled release and the initial Diffusion of SL (Mt/M∞ < 2/3) could be well described by Fickian Diffusion equation. The thermodynamic parameters suggested that the Diffusion of SL was endothermic and spontaneous, and the increase of temperature and PLLA content in film favored the Diffusion of SL.