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This paper aims at developing a mathematic model to characterize the mechanical properties of single-walled carbon nanotubes (SWCNTs). The carbon-carbon (C−C) bonds between two adjacent atoms are modeled as Euler beams. According to the relationship of Tersoff-Brenner force theory and potential energy acting on C−C bonds, material constants of beam element are determined at the atomic scale. Based on the elastic deformation energy and mechanical equilibrium of a unit in graphite sheet, simply form ED equations of calculating Young's modulus of armchair and zigzag graphite sheets are derived. Following with the geometrical relationship of SWCNTs in cylindrical coordinates and the structure mechanics approach, Young's modulus and Poisson's ratio of armchair and zigzag SWCNTs are also investigated. The results show that the approach to research mechanical properties of SWCNTs is a concise and valid method. We consider that it will be useful technique to progress on this type of investigation.

The effectiveness of a multifunctional scaffold produced by the electrospinning of emulsions composed of organic PLGA and aqueous collagen-like protein (denoted as Fol-8Col) solutions is demonstrated. The resultant Fol-8Col/PLGA fibrous scaffolds with homogeneous morphology have mean fiber diameters from 600 to 2,000 nm. A uniform distribution of encapsulated Fol-8Col in the fibers is observed by fluorescence microscopy. TEM is used to clarify the representative core/sheath structure of emulsion electrospun Fol-8Col/PLGA fibers. Preliminary release assessment of encapsulated Fol-8Col shows results of sustained release for more than one month from the Fol-8Col/PLGA fibrous mats. The cytocompatibility of fibroblast cell line L929 with the fibrous composite seems promosing.

The Young's modulus and the thickness of graphene sheets (GSs) are the two major material constants when continuum mechanical models are used to analyze the mechanical behaviors of GSs. It should be pointed out that the equivalent Young's modulus and the thickness of GSs should correspond to both stretching and bending loading conditions. In this Letter, the same as “Yakobson paradox,” we predicted the equivalent Young's modulus and the thickness of GSs using an analytical method linked with an atomic interaction based continuum model and a continuum elastic model. Based on the proposed method, by unifying the Young's modulus of GSs in the cases of both stretching and bending, and by determining the matching thickness in the same time, the equivalent Young's modulus and the thickness of GSs utilized in continuum mechanical models are calculated and proposed to be 2.81 TPa and 1.27 Å, respectively.

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