Bio-Inspired Carbon Nanotube-Polymer Composite Yarns with Hydrogen Bond-Mediated Lateral Interactions
Department of Mechanical Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3111, United States. ACS Nano
(Impact Factor: 12.88).
04/2013; 7(4). DOI: 10.1021/nn400346r
Polymer composite yarns containing a high loading of double-walled carbon nanotubes (DWNTs) have been developed in which the inherent acrylate-based organic coating on the surface of the DWNT bundles interacts strongly with poly(vinyl alcohol) (PVA) through an extensive hydrogen-bond network. This design takes advantage of a toughening mechanism seen in spider silk and collagen, which contain an abundance of hydrogen bonds that can break and reform, allowing for large deformation while maintaining structural stability. Similar to that observed in natural materials, unfolding of the polymeric matrix at large deformations increases ductility without sacrificing stiffness. As the PVA content in the composite increases, the stiffness and energy to failure of the composite also increases up to an optimal point, beyond which mechanical performance in tension decreases. Molecular dynamics (MD) simulations confirm this trend, showing the dominance of nonproductive hydrogen bonding between PVA molecules at high PVA contents, which lubricates the interface between DWNTs.
Available from: Al'ona Furmanchuk
- "Other valence terms (angle and torsion) are defined in terms of the same bond orders so that all interactions go to zero smoothly as the bonds break. ReaxFF parameters have previously been developed for systems consisting of C, N, O and H atoms    , and ReaxFF simulations based on these parameters show good qualitative correspondence with experiment in the initial stages of PAN   carbonization (without nanofillers) and phenolic pyrolysis . The accuracy of the force field has also been tested [2,39– 41] through comparisons with density functional theory as well as density functional tight binding theory results, and was considered adequate for simulations at the temperatures of interest in this work. "
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ABSTRACT: Understanding the atomistic mechanisms of carbon structure formation during templated multi-step
carbonization is very important for further optimization of carbon fiber mechanical properties. Here with
use of reactive force field molecular dynamics we have elucidated the mechanism driving double-walled
carbon nanotube- and graphite nanoparticle-based in situ templating of polyacrylonitrile derived fibers.
Depending on carbonization temperature, the mechanism involves either physisorption (physical templating)
or chemisorption (chemical templating) of the fiber medium to the template surface. In either
case, strong interaction between template and medium leads to the production of aligned structures that
are more robust for nanotubes than graphite. We provide a unique analysis of atomistic simulations that
enables quantitative comparison of templating results with the relevant electron diffraction data
Carbon 07/2015; 94:694-704. DOI:10.1016/j.carbon.2015.07.048 · 6.20 Impact Factor
Available from: Gang Tang
- "These materials are formed by the combination of nanoscale inorganic and organic domains, and offer exceptional opportunities not only to combine the important properties from both materials but also to create entirely new compositions with truly unique properties   . In the early ages of the polymer composites research, silicates, double hydroxides (LDHs) and carbon nanotubes (CNTs) were the most widely investigated   . However, in the present, graphene-based materials already dominated in this field  . "
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ABSTRACT: Functionalized graphene oxide-reinforced poly(vinyl alcohol) hybrid composites were prepared by using the sol–gel method. This method not only provided a “green” strategy for fabricating the graphene oxide-based composites, but also realized the covalent functionalization of graphene oxide nanosheets with polymer matrix. The morphology, thermal, fire resistance and mechanical properties of the f-GNS/poly(vinyl alcohol) hybrid composites were systematically studied. The transmission electron microscopy analyses demonstrated that f-GNS was homogeneously dispersed in the poly(vinyl alcohol) matrix. Combining with a series of analyses and characterizations, it was observed that the functionalization of graphene oxide with conjugated organosilanes was favorable for improving mechanical, thermal properties and flame retardance of the composites, which was mainly attributed to the homogeneous dispersion of functionalized graphene oxide in the polymer matrix and strong interfacial interactions between the two components.
Composites Science and Technology 10/2014; 102:51–58. DOI:10.1016/j.compscitech.2014.06.029 · 3.57 Impact Factor
Available from: Igor Ostanin
- "Carbon nanotube (CNT) based materials, and in particular CNT bundles and CNT ropes, show great promise for technological applications             . Twisted CNT yarns are candidate structures for electromechanical torsional actuators and artificial muscles . "
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ABSTRACT: The recently developed distinct element method for mesoscale modeling of carbon nanotubes is extended to account for energy dissipation and then applied to character-ize the constitutive behavior of crystalline carbon nanotube bundles subjected to simple tension and to simple shear loadings. It is shown that if these structures are sufficiently long and thick, then they become representative volume elements. The predicted initial stiffness and strength of the representative volumes are in agreement with reported ex-perimental data. The simulations demonstrate that energy dissipation plays a central role in the mechanical response and deformation kinematics of carbon nanotube bundles.
Journal of Applied Mechanics 06/2014; 81(6). DOI:10.1115/1.4026484 · 1.37 Impact Factor
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