The goal of this work was to use molecular dynamics (MD) simulations to build amorphous surface layers of polypropylene (PP) and cellulose and to inspect their physical and interfacial properties. A new method to prod...
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The goal of this work was to use molecular dynamics (MD) simulations to build amorphous surface layers of polypropylene (PP) and cellulose and to inspect their physical and interfacial properties. A new method to produce molecular models for these surfaces was developed, which involved the use of a “soft” confining layer comprised of a xenon crystal. This method compacts the polymers into a density distribution and a degree of molecular surface roughness that corresponds well to experimental values. In addition, calculated properties such as density, cohesive energy density, coefficient of thermal expansion, and the surface energy agree with experimental values and thus validate the use of soft confining layers. The method can be applied to polymers with a linear backbone such as PP as well as those whose backbones contain rings, such as cellulose. The developed PP and cellulose surfaces were characterized by their interactions with water. It was found that a water nanodroplet spreads on the amorphous cellulose surfaces, but there was no significant change in the dimension of the droplet on the PP surface; the resulting MD water contact angles on PP and amorphous cellulose surfaces were determined to be 106 and 33°, respectively. [ABSTRACT FROM AUTHOR]
作者：
Shu ZhangYing LiGuanjie XuShuli LiYao LuOzan ToprackiXiangwu ZhangFiber and Polymer Science Program
Department of Textile Engineering Chemistry and Science North Carolina State University Raleigh NC..Fiber and Polymer Science Program Department of Textile Engineering Chemistry and Science North Carolina State University Raleigh NC..Fiber and Polymer Science Program Department of Textile Engineering Chemistry and Science North Carolina State University Raleigh NC..Fiber and Polymer Science Program Department of Textile Engineering Chemistry and Science North Carolina State University Raleigh NC..Fiber and Polymer Science Program Department of Textile Engineering Chemistry and Science North Carolina State University Raleigh NC..Fiber and Polymer Science Program Department of Textile Engineering Chemistry and Science North Carolina State University Raleigh NC..Fiber and Polymer Science Program Department of Textile Engineering Chemistry and Science North Carolina State University Raleigh NC..
Li2MnSiO4 has an extremely high theoretical capacity of 332 mAh?g?1. However, only around half of this capacity has been realized in practice and the capacity retention during cycling is also low. In this study, Li2Mn...
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Li2MnSiO4 has an extremely high theoretical capacity of 332 mAh?g?1. However, only around half of this capacity has been realized in practice and the capacity retention during cycling is also low. In this study, Li2MnSiO4/carbon composite nanofibers were prepared by a combination of electrospinning and heat treatment. The one-dimensional continuous carbon nanofiber matrix serves as long-distance conductive pathways for both electrons and ions. The composite nanofiber structure avoids the aggregation of Li2MnSiO4 particles, which in turn enhances the electrode conductivity and promotes the reaction kinetics. The resultant Li2MnSiO4/carbon composite nanofibers were used as the cathode material for Li-ion batteries, and they delivered high charge and discharge capacities of 218 and 185 mAh?g?1, respectively, at the second cycle. In addition, the capacity retention of Li2MnSiO4 at the first 20th cycles increased from 37% to 54% in composite nanofibers.
This article was originally published online on 29 September 2014 with an error in the journal title of Ref. 36. The corrected reference appears below:
This article was originally published online on 29 September 2014 with an error in the journal title of Ref. 36. The corrected reference appears below:
Brilliant, iridescent colors found on the bodies and wings of many birds, butterflies and moths are produced by structural variations and have been the subject of study for centuries. Such brilliant colors have been d...
Brilliant, iridescent colors found on the bodies and wings of many birds, butterflies and moths are produced by structural variations and have been the subject of study for centuries. Such brilliant colors have been described as metallic colors due to the saturation or purity of the color produced and have attracted the attention of great scientists like Newton, Michelson and Lord Rayleigh. It was recognized early on that such colors arise from physical effects such as interference or diffraction as opposed to colors that are normally produced due to the presence of chromophores which absorb or emit light. Common examples of physical colors are some butterfly wings [1], color of Indigo snake skin [2], hummingbird feathers [3,4], arthropod cuticles [which are due to selective reflection of color from the solidified cholesteric phase of chitin crystallites] [5], gemstones like opal [6,7], and some crystals like potassium chlorate [8]. While the origins of such colors are well understood the properties of color and color specification have not received much attention.
Li2MnSiO4 has an extremely high theoretical capacity of 332 mAh?g?1. However, only around half of this capacity has been realized in practice and the capacity retention during cycling is also low. In this study, Li2Mn...
详细信息
Li2MnSiO4 has an extremely high theoretical capacity of 332 mAh?g?1. However, only around half of this capacity has been realized in practice and the capacity retention during cycling is also low. In this study, Li2MnSiO4/carbon composite nanofibers were prepared by a combination of electrospinning and heat treatment. The one-dimensional continuous carbon nanofiber matrix serves as long-distance conductive pathways for both electrons and ions. The composite nanofiber structure avoids the aggregation of Li2MnSiO4 particles, which in turn enhances the electrode conductivity and promotes the reaction kinetics. The resultant Li2MnSiO4/carbon composite nanofibers were used as the cathode material for Li-ion batteries, and they delivered high charge and discharge capacities of 218 and 185 mAh?g?1, respectively, at the second cycle. In addition, the capacity retention of Li2MnSiO4 at the first 20th cycles increased from 37% to 54% in composite nanofibers.
Adsorbent of calcium alginate/multi-walled carbon nanotubes (CA/MWCNTs) composite fiber was prepared by wet spinning. Adsorptions of methyl orange (MO) anionic dyes onto CA/MWCNTs composite fiber were investigated wit...
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Adsorbent of calcium alginate/multi-walled carbon nanotubes (CA/MWCNTs) composite fiber was prepared by wet spinning. Adsorptions of methyl orange (MO) anionic dyes onto CA/MWCNTs composite fiber were investigated with respect to MWCNTs content, initial dye concentration and pH values. Results illustrated that introduction of MWCNTs could obviously increase the adsorption capacity ( qe ) of MO onto CA/MWCNTs composite fibers. The equilibrium adsorption data were analyzed using two widely applied isotherms: Langmuir and Freundlich. The results showed that Langmuir isotherm fitted the experimental results well.
Adsorbent of calcium alginate/multi-walled carbon nanotubes(CA/MWCNTs) composite fiber was prepared by wet spinning. Adsorptions of methyl orange(MO) anionic dyes onto CA/MWCNTs composite fiber were investigated with ...
详细信息
Adsorbent of calcium alginate/multi-walled carbon nanotubes(CA/MWCNTs) composite fiber was prepared by wet spinning. Adsorptions of methyl orange(MO) anionic dyes onto CA/MWCNTs composite fiber were investigated with respect to MWCNTs content, initial dye concentration and p H values. Results illustrated that introduction of MWCNTs could obviously increase the adsorption capacity(qe) of MO onto CA/MWCNTs composite fibers. The equilibrium adsorption data were analyzed using two widely applied isotherms: Langmuir and Freundlich. The results showed that Langmuir isotherm ?tted the experimental results well.
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