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Morimitsu Y, Matsuno H, Oda Y, Yamamoto S, Tanaka K. Direct visualization of cooperative adsorption of a string-like molecule onto a solid. SCIENCE ADVANCES 2022; 8:eabn6349. [PMID: 36223469 PMCID: PMC9555780 DOI: 10.1126/sciadv.abn6349] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
Natural systems, composite materials, and thin-film devices adsorb macromolecules in different phases onto their surfaces. In general, polymer chains form interfacial layers where their aggregation states and thermal molecular motions differ from the bulk. Here, we visualize well-defined double-stranded DNAs (dsDNAs) using atomic force microscopy and molecular dynamics simulations to clarify the adsorption mechanism of polymer chains onto solid surfaces. Initially, short and long dsDNAs are individually and cooperatively adsorbed, respectively. Cooperative adsorption involves intertwining of multiple chains. The dependence of adsorption on the chain affects the formation of the interfacial layer, realizing different mechanical properties of DNA/filler bulk composites. These findings will contribute to the development of light and durable polymer composites and films for various industrial, biomedical, and environmental applications.
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Affiliation(s)
- Yuma Morimitsu
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Hisao Matsuno
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
- Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yukari Oda
- Division of Applied Chemistry and Biochemical Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8561, Japan
| | - Satoru Yamamoto
- Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Keiji Tanaka
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
- Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
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Vargas-Lara F, Starr FW, Douglas JF. Solution properties of spherical gold nanoparticles with grafted DNA chains from simulation and theory. NANOSCALE ADVANCES 2022; 4:4144-4161. [PMID: 36285224 PMCID: PMC9514572 DOI: 10.1039/d2na00377e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/30/2022] [Indexed: 06/16/2023]
Abstract
There has been a rapidly growing interest in the use of functionalized Au nanoparticles (NPs) as platforms in multiple applications in medicine and manufacturing. The sensing and targeting characteristics of these NPs, and the realization of precisely organized structures in manufacturing applications using such NPs, depend on the control of their surface functionalization. NP functionalization typically takes the form of polymer grafted layers, and a detailed knowledge of the chemical and structural properties of these layers is required to molecularly engineer the particle characteristics for specific applications. However, the prediction and experimental determination of these properties to enable the rational engineering of these particles is a persistent problem in the development of this class of materials. To address this situation, molecular dynamic simulations were performed based on a previously established coarse-grained single-stranded DNA (ssDNA) model to determine basic solution properties of model ssDNA-grafted NP-layers under a wide range of conditions. In particular, we emphasize the calculation of the hydrodynamic radius for ssDNA-grafted Au NPs as a function of structural parameters such as ssDNA length, NP core size, and surface coverage. We also numerically estimate the radius of gyration and the intrinsic viscosity of these NPs, which in combination with hydrodynamic radius estimates, provide valuable information about the fluctuating structure of the grafted polymer layers. We may then understand the origin of the commonly reported variation in effective NP "size" by different measurement methods, and then exploit this information in connection to material design and characterization in connection with the ever-growing number of applications utilizing polymer-grafted NPs.
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Affiliation(s)
- Fernando Vargas-Lara
- Departments of Physics & Molecular Biology & Biochemistry, Wesleyan University Middletown CT 06459 USA
| | - Francis W Starr
- Departments of Physics & Molecular Biology & Biochemistry, Wesleyan University Middletown CT 06459 USA
| | - Jack F Douglas
- Materials Science & Engineering Division, National Institute of Standards and Technology Gaithersburg Maryland 20899 USA
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3
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Morrin GT, Kienle DF, Schwartz DK. Diffusion of Short Semiflexible DNA Polymer Chains in Strong and Moderate Confinement. ACS Macro Lett 2021; 10:1191-1195. [PMID: 35549041 DOI: 10.1021/acsmacrolett.1c00470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In many technological applications, DNA is confined within nanoenvironments that are smaller than the size of the unconfined polymer in solution. However, the dependence of the diffusion coefficient on molecular weight and characteristic confinement dimension remains poorly understood in this regime. Here, convex lens-induced confinement (CLiC) was leveraged to examine how the diffusion of short DNA fragments varied as a function of slit height by using single-molecule fluorescence tracking microscopy. The diffusion coefficient followed approximate power law behavior versus confinement height, with exponents of 0.27 ± 0.01, 0.32 ± 0.02, and 0.42 ± 0.06 for 692, 1343, and 2686 base pair chains, respectively. The weak dependence on slit height suggests that shorter semiflexible chains may adopt increasingly rodlike conformations and therefore experience weaker excluded-volume interactions as the confinement dimension is reduced. The diffusion coefficient versus molecular weight also exhibited apparent power law behavior, with exponents that varied slightly (from -0.89 to -0.85) with slit height, consistent with hydrodynamic interactions intermediate between Rouse and Zimm model predictions.
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Affiliation(s)
- Gregory T Morrin
- Department of Chemical and Biological Engineering University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel F Kienle
- Department of Chemical and Biological Engineering University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering University of Colorado Boulder, Boulder, Colorado 80309, United States
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Teng Y, Andersen NT, Chen JZY. Statistical Properties of a Slit-Confined Wormlike Chain of Finite Length. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Yue Teng
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Nigel T. Andersen
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Jeff Z. Y. Chen
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Ghosh S, Karedla N, Gregor I. Single-molecule confinement with uniform electrodynamic nanofluidics. LAB ON A CHIP 2020; 20:3249-3257. [PMID: 32760965 DOI: 10.1039/d0lc00398k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
To date, we could not engineer Nature's ability to dynamically handle diffusing single molecules in the liquid-phase as it takes place in pore-forming proteins and tunnelling nanotubes. Consistent handling of individual single molecules in a liquid is of paramount importance to fundamental molecular studies and technological benefits, like single-molecule level separation and sorting for early biomedical diagnostics, microscopic studies of molecular interactions and electron/optical microscopy of molecules and nanomaterials. We can consistently resolve the dynamics of diffusing single molecules if they are confined within a uniform dielectric environment at nanometre length-scales. A uniform dielectric environment is the key characteristic since intrinsic electronic properties of molecules were modified while interacting with any surfaces, and the effect is not the same from one dielectric surface to another. We present dynamic nanofluidic detection of optically active single molecules in a liquid. An all-silica nanofluidic environment was used to electrokinetically handle individual single-molecules where molecular shot noise was resolved. We recorded the single-molecule motion of small fragments of DNA, carbon-nanodots, and organic fluorophores in water. The electrokinetic 1D molecular mass transport under two-focus fluorescence correlation spectroscopy (2fFCS) showed confinement-induced modified molecular interactions (due to various inter-molecular repulsive and attractive forces), which have been theoretically interpreted as molecular shot noise. Our demonstration of high-throughput nanochannel fabrication, 2fFCS-based 1D confined detection of fast-moving single molecules and fundamental understanding of molecular shot noise may open an avenue for single-molecule experiments where physical manipulation of dynamics is necessary.
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Affiliation(s)
- Siddharth Ghosh
- III. Institute of Physics - Biophysics and Complex Systems, University of Göttingen, Göttingen, Germany.
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Roy S, Luzhbin DA, Chen YL. Investigation of nematic to smectic phase transition and dynamical properties of strongly confined semiflexible polymers using Langevin dynamics. SOFT MATTER 2018; 14:7382-7389. [PMID: 30203825 DOI: 10.1039/c8sm01100a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigated the nematic to smectic phase transition for strongly confined semiflexible polymer solutions in slit-like confinements using GPU-accelerated Langevin dynamics. We characterized the phase transitions from the nematic to smectic phases for semi-flexible polymer solutions as the polymer density increased. The dependence for the lyotropic nematic to smectic transition can be collapsed by scaling exponents between 0.2 and 0.3. The smectic C phase is found for all the cases with the polymer orientation director tilted with respect to smectic layer lateral alignment. As the chain rigidity increases, the transition density decreases for systems in which the polymer persistence length (P) to slit height (H) ratios are 1.25, 2.5, 3.75, 5 and 25. We also characterized the polymer dynamics for the isotropic-nematic-smectic transitions. The overall polymer diffusivity decreased steadily as the polymer density increased. We observed anomalous polymer diffusion along the nematic director near the isotropic-nematic transition, similar to previously reported behavior for nematic-forming ellipsoids. Polymer diffusivity decreased sharply by two orders of magnitude upon the nematic-smectic transition.
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Affiliation(s)
- Supriya Roy
- Institute of Physics, Academia Sinica, Taipei, Taiwan, Republic of China.
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Cheong GK, Li X, Dorfman KD. Evidence for the extended de Gennes regime of a semiflexible polymer in slit confinement. Phys Rev E 2018; 97:022502. [PMID: 29479576 PMCID: PMC5823612 DOI: 10.1103/physreve.97.022502] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We use off-lattice, pruned-enriched Rosenbluth method (PERM) simulations to compute the confinement free energy of a real wormlike chain of effective width w and persistence length lp in a slit of height H. For slit heights much larger than the persistence length of the polymer and much smaller than the thermal blob size, the excess free energy of the confined chain is consistent with a modified version of the scaling theory for the extended de Gennes regime in a channel that reflects the blob statistics in slit confinement. Explicitly, for channel sizes [Formula: see text], the difference between the confinement free energy of the real chain and that of an ideal chain scales like w/H.
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Affiliation(s)
- Guo Kang Cheong
- Department of Chemical Engineering and Materials Science, University of Minnesota – Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
| | - Xiaolan Li
- Department of Chemical Engineering and Materials Science, University of Minnesota – Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota – Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
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Vargas-Lara F, Starr FW, Douglas JF. Molecular rigidity and enthalpy-entropy compensation in DNA melting. SOFT MATTER 2017; 13:8309-8330. [PMID: 29057399 DOI: 10.1039/c7sm01220a] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Enthalpy-entropy compensation (EEC) is observed in diverse molecular binding processes of importance to living systems and manufacturing applications, but this widely occurring phenomenon is not sufficiently understood from a molecular physics standpoint. To gain insight into this fundamental problem, we focus on the melting of double-stranded DNA (dsDNA) since measurements exhibiting EEC are extensive for nucleic acid complexes and existing coarse-grained models of DNA allow us to explore the influence of changes in molecular parameters on the energetic parameters by using molecular dynamics simulations. Previous experimental and computational studies have indicated a correlation between EEC and changes in molecular rigidity in certain binding-unbinding processes, and, correspondingly, we estimate measures of DNA molecular rigidity under a wide range of conditions, along with resultant changes in the enthalpy and entropy of binding. In particular, we consider variations in dsDNA rigidity that arise from changes of intrinsic molecular rigidity such as varying the associative interaction strength between the DNA bases, the length of the DNA chains, and the bending stiffness of the individual DNA chains. We also consider extrinsic changes of molecular rigidity arising from the addition of polymer additives and geometrical confinement of DNA between parallel plates. All our computations confirm EEC and indicate that this phenomenon is indeed highly correlated with changes in molecular rigidity. However, two distinct patterns relating to how DNA rigidity influences the entropy of association emerge from our analysis. Increasing the intrinsic DNA rigidity increases the entropy of binding, but increases in molecular rigidity from external constraints decreases the entropy of binding. EEC arises in numerous synthetic and biological binding processes and we suggest that changes in molecular rigidity might provide a common origin of this ubiquitous phenomenon in the mutual binding and unbinding of complex molecules.
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Affiliation(s)
- Fernando Vargas-Lara
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
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Vargas-Lara F, Hassan AM, Mansfield ML, Douglas JF. Knot Energy, Complexity, and Mobility of Knotted Polymers. Sci Rep 2017; 7:13374. [PMID: 29042576 PMCID: PMC5645353 DOI: 10.1038/s41598-017-12461-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 09/08/2017] [Indexed: 11/15/2022] Open
Abstract
The Coulomb energy E C is defined by the energy required to charge a conductive object and scales inversely to the self-capacity C, a basic measure of object size and shape. It is known that C is minimized for a sphere for all objects having the same volume, and that C increases as the symmetry of an object is reduced at fixed volume. Mathematically similar energy functionals have been related to the average knot crossing number 〈m〉, a natural measure of knot complexity and, correspondingly, we find E C to be directly related to 〈m〉 of knotted DNA. To establish this relation, we employ molecular dynamics simulations to generate knotted polymeric configurations having different length and stiffness, and minimum knot crossing number values m for a wide class of knot types relevant to the real DNA. We then compute E C for all these knotted polymers using the program ZENO and find that the average Coulomb energy 〈E C〉 is directly proportional to 〈m〉. Finally, we calculate estimates of the ratio of the hydrodynamic radius, radius of gyration, and the intrinsic viscosity of semi-flexible knotted polymers in comparison to the linear polymeric chains since these ratios should be useful in characterizing knotted polymers experimentally.
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Affiliation(s)
- Fernando Vargas-Lara
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
| | - Ahmed M Hassan
- Department of Computer Science and Electrical Engineering, University of Missouri-Kansas City, Kansas City, MO, 64110, USA
| | - Marc L Mansfield
- Bingham Research Center, Utah State University, Vernal, UT, 84078, USA
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
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Vargas–Lara F, Mansfield ML, Douglas JF. Universal interrelation between measures of particle and polymer size. J Chem Phys 2017; 147:014903. [PMID: 28688424 PMCID: PMC11005114 DOI: 10.1063/1.4991011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The characterization of many objects involves the determination of a basic set of particle size measures derived mainly from scattering and transport property measurements. For polymers, these basic properties include the radius of gyration Rg, hydrodynamic radius Rh, intrinsic viscosity [η], and sedimentation coefficient S, and for conductive particles, the electric polarizability tensor αE and self-capacity C. It is often found that hydrodynamic measurements of size deviate from each other and from geometric estimates of particle size when the particle or polymer shape is complex, a phenomenon that greatly complicates both nanoparticle and polymer characterizations. The present work explores a general quantitative relation between αE, C, and Rg for nanoparticles and polymers of general shape and the corresponding properties η, Rh, and Rg using a hydrodynamic-electrostatic property interrelation.
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Affiliation(s)
- Fernando Vargas–Lara
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Marc L. Mansfield
- Bingham Research Center, Utah State University, Vernal, Utah 84078, USA
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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Mansfield ML, Tsortos A, Douglas JF. Persistent draining crossover in DNA and other semi-flexible polymers: Evidence from hydrodynamic models and extensive measurements on DNA solutions. J Chem Phys 2016; 143:124903. [PMID: 26429037 DOI: 10.1063/1.4930918] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although the scaling theory of polymer solutions has had many successes, this type of argument is deficient when applied to hydrodynamic solution properties. Since the foundation of polymer science, it has been appreciated that measurements of polymer size from diffusivity, sedimentation, and solution viscosity reflect a convolution of effects relating to polymer geometry and the strength of the hydrodynamic interactions within the polymer coil, i.e., "draining." Specifically, when polymers are expanded either by self-excluded volume interactions or inherent chain stiffness, the hydrodynamic interactions within the coil become weaker. This means there is no general relationship between static and hydrodynamic size measurements, e.g., the radius of gyration and the hydrodynamic radius. We study this problem by examining the hydrodynamic properties of duplex DNA in solution over a wide range of molecular masses both by hydrodynamic modeling using a numerical path-integration method and by comparing with extensive experimental observations. We also considered how excluded volume interactions influence the solution properties of DNA and confirm that excluded volume interactions are rather weak in duplex DNA in solution so that the simple worm-like chain model without excluded volume gives a good leading-order description of DNA for molar masses up to 10(7) or 10(8) g/mol or contour lengths between 5 μm and 50 μm. Since draining must also depend on the detailed chain monomer structure, future work aiming to characterize polymers in solution through hydrodynamic measurements will have to more carefully consider the relation between chain molecular structure and hydrodynamic solution properties. In particular, scaling theory is inadequate for quantitative polymer characterization.
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Affiliation(s)
- Marc L Mansfield
- Bingham Research Center, Utah State University, Vernal, Utah 84078, USA
| | - Achilleas Tsortos
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas (FORTH), Vassilika Vouton, 70013 Heraklion, Greece
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institutes of Standards and Technology, Gaithersburg, Maryland 20899, USA
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Vargas-Lara F, Hassan AM, Garboczi EJ, Douglas JF. Intrinsic conductivity of carbon nanotubes and graphene sheets having a realistic geometry. J Chem Phys 2015; 143:204902. [PMID: 26627970 PMCID: PMC4879685 DOI: 10.1063/1.4935970] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The addition of carbon nanotubes (CNTs) and graphene sheets (GSs) into polymeric materials can greatly enhance the conductivity and alter the electromagnetic response of the resulting nanocomposite material. The extent of these property modifications strongly depends on the structural parameters describing the CNTs and GSs, such as their shape and size, as well as their degree of particle dispersion within the polymeric matrix. To model these property modifications in the dilute particle regime, we determine the leading transport virial coefficients describing the conductivity of CNT and GS composites using a combination of molecular dynamics, path-integral, and finite-element calculations. This approach allows for the treatment of the general situation in which the ratio between the conductivity of the nanoparticles and the polymer matrix is arbitrary so that insulating, semi-conductive, and conductive particles can be treated within a unified framework. We first generate ensembles of CNTs and GSs in the form of self-avoiding worm-like cylinders and perfectly flat and random sheet polymeric structures by using molecular dynamics simulation to model the geometrical shapes of these complex-shaped carbonaceous nanoparticles. We then use path-integral and finite element methods to calculate the electric and magnetic polarizability tensors (αE, αM) of the CNT and GS nanoparticles. These properties determine the conductivity virial coefficient σ in the conductive and insulating particle limits, which are required to estimate σ in the general case in which the conductivity contrast Δ between the nanoparticle and the polymer matrix is arbitrary. Finally, we propose approximate relationships for αE and αM that should be useful in materials design and characterization applications.
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Affiliation(s)
- Fernando Vargas-Lara
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Ahmed M Hassan
- Materials and Structural Systems Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Edward J Garboczi
- Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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