Brownian Dynamics (BD) is an attractive approach to simulate solute nanoparticles in a suspension... more Brownian Dynamics (BD) is an attractive approach to simulate solute nanoparticles in a suspension of solvent molecules because it exploits the separation of time scales between solvent and solute dynamics to avoid explicit representation of the solvent molecules. In BD a nanoparticle's velocity evolves because of interaction with other nanoparticles through a systematic pairwise interaction force, while the effect of the solvent molecules on the nanoparticles is represented by a combination of frictional and random forces (Langevin part). This Langevin equation for the velocity is ...
Aps Division of Fluid Dynamics Meeting Abstracts, 2009
Nanoparticle synthesis in turbulent reactors subjects anoparticle aggregates to a homogeneous, ti... more Nanoparticle synthesis in turbulent reactors subjects anoparticle aggregates to a homogeneous, time-varying shear flow. The shear flow results in anisotropic clusters and it is of interest to characterize the structural properties of these clusters and their effects on initiation and acceleration of aggregation, the restructuring of clusters, and their breakage. The anisotropic structure of a sheared cluster is characterized by the ratio of the major to minor axis length of the approximating ellipsoid oriented along the cluster moment of inertia tensor's principal ...
Physical review. E, Statistical, nonlinear, and soft matter physics, 2014
Aggregation of colloidal particles under shear is studied in model systems using a Langevin dynam... more Aggregation of colloidal particles under shear is studied in model systems using a Langevin dynamics model with an improved interparticle interaction potential. In the absence of shear, aggregates that form are characterized by compact structure at small scales and ramified structure at larger scales. This confirms the structural crossover mechanism previously suggested by Sorensen and coworkers, that colloidal aggregation occurs due to monomer addition at small scales and due to cluster-cluster aggregation at large scales. The fractal dimension of nonsheared aggregates is scale-dependent. Smaller aggregates have a higher fractal dimension than larger ones, but the radius of gyration where this crossover occurs is independent of potential well depth for sufficiently deep wells. When these aggregates are subjected to shear they become anisotropic and form extended cigar-like structures. The size of sheared anisotropic aggregates in the direction perpendicular to the shear flow is lim...
Intense electrical arcs were applied to thermoplastic (polyamide 66) and thermoset (fiber reinfor... more Intense electrical arcs were applied to thermoplastic (polyamide 66) and thermoset (fiber reinforced laminated polyester) materials and the resulting carbonization/metallization process was studied on a sub-micron scale with atomic force microscopy to understand very initial stage of reorganization of surface morphology. These changes can be critical in dramatic changes in surface resistivity preceding electric breakthrough. The surface microroughness and the localization of micro- and nanoparticles at the center (arc initiation area) and along the edges of the samples were significantly different for different arc regimes. We suggested that for thermoset, the material is pulled out of the surface in the arc formation area (the center of sample). Afterwards, the intensive re-deposition occurred along the edges enhancing non-uniform ablation around the arc initiation area. In contrary, for thermoplastic samples, the entire polymer surface was re-melted that resulted in dramatic smoothing of the initially non-uniform surface morphology.
Nanoscale uniform films containing gold nanoparticle and polyelectrolyte multilayer structures we... more Nanoscale uniform films containing gold nanoparticle and polyelectrolyte multilayer structures were fabricated by the using spin-assembly or spin-assisted layer-by-layer (SA-LbL) deposition technique. These SA-LbL films with a general formula [Au/(PAH-PSS)nPAH]m possessed a well-organized microstructure with uniform surface morphology and high surface quality at a large scale (tens of micrometers across). Plasmon resonance peaks from isolated nanoparticles and interparticle interactions were revealed in the UV-visible extinction spectra of the SA-LbL films. All films showed the strong extinction peak in the region of 510-550 nm, which is due to the plasmon resonance of the individual gold nanoparticles redshifted because of a local dielectric environment. For films with sufficient density of gold nanoparticles within the layers, the second strong peak was consistently observed between 620 and 660 nm, which is the collective plasmon resonance from intralayer interparticle coupling. Finally, we suggested that, for certain film designs, interlayer interparticle resonance might be revealed as an independent contribution at 800 nm in UV-visible spectra. The observation of independent and concurrent individual, intralayer, and interlayer plasmon resonances can be critical for sensing applications, which involve monitoring of optomechanical properties of ultrathin optically active compliant membranes.
Bulletin of the American Physical Society, Nov 20, 2005
Brownian Dynamics (BD) is an attractive approach to simulate solute nanoparticles in a suspension... more Brownian Dynamics (BD) is an attractive approach to simulate solute nanoparticles in a suspension of solvent molecules because it exploits the separation of time scales between solvent and solute dynamics to avoid explicit representation of the solvent molecules. In BD a nanoparticle's velocity evolves because of interaction with other nanoparticles through a systematic pairwise interaction force, while the effect of the solvent molecules on the nanoparticles is represented by a combination of frictional and random forces (Langevin part). This Langevin equation for the velocity is ...
Light-scattering data for the aggregation of colloidal nanoparticles shows that hybrid aggregates... more Light-scattering data for the aggregation of colloidal nanoparticles shows that hybrid aggregates with two different fractal dimensions can be formed depending on the magnitude and duration of the applied shear (CM Sorensen's group, Kansas State University). Formation of such super-aggregate structures with D f= 2.55, and their reverting to D f= 1.8 depending on the shear condition is not completely explained yet. Simulations can provide insight into this behavior, provided they can accurately capture the essential aggregation ...
Bulletin of the American Physical Society, Nov 24, 2008
Aggregation of nanoparticles in liquid suspension is a phenomenon that affects the design and sca... more Aggregation of nanoparticles in liquid suspension is a phenomenon that affects the design and scale-up of process equipment for nanoparticle synthesis. The radial distribution function of nanoparticle pairs is an essential statistic characterizing multiparticle dynamics that must be captured by Brownian dynamics (BD) simulations in order to accurately simulate the structure of nanoparticle aggregates. Molecular dynamics (MD) simulations of a model aggregating system are used as a benchmark to evaluate the simplest specification of the potential of mean force (PMF) in ...
Bulletin of the American Physical Society, Nov 23, 2009
Nanoparticle synthesis in turbulent reactors subjects anoparticle aggregates to a homogeneous, ti... more Nanoparticle synthesis in turbulent reactors subjects anoparticle aggregates to a homogeneous, time-varying shear flow. The shear flow results in anisotropic clusters and it is of interest to characterize the structural properties of these clusters and their effects on initiation and acceleration of aggregation, the restructuring of clusters, and their breakage. The anisotropic structure of a sheared cluster is characterized by the ratio of the major to minor axis length of the approximating ellipsoid oriented along the cluster moment of inertia tensor's principal ...
ABSTRACT Freely suspended gold nanoparticle arrays have been fabricated by encapsulation into lay... more ABSTRACT Freely suspended gold nanoparticle arrays have been fabricated by encapsulation into layer-by-layer nanomembranes. Such nanomembranes (see Figure) retain outstanding micromechanical properties and have an anisotropic mechanical response due to the uniformly oriented nanoparticle-containing stripes. Periodic variation of the Raman scattering across the microarrays is displayed (inset).
Brownian Dynamics (BD) is an attractive approach to simulate solute nanoparticles in a suspension... more Brownian Dynamics (BD) is an attractive approach to simulate solute nanoparticles in a suspension of solvent molecules because it exploits the separation of time scales between solvent and solute dynamics to avoid explicit representation of the solvent molecules. In BD a nanoparticle's velocity evolves because of interaction with other nanoparticles through a systematic pairwise interaction force, while the effect of the solvent molecules on the nanoparticles is represented by a combination of frictional and random forces (Langevin part). This Langevin equation for the velocity is ...
Aps Division of Fluid Dynamics Meeting Abstracts, 2009
Nanoparticle synthesis in turbulent reactors subjects anoparticle aggregates to a homogeneous, ti... more Nanoparticle synthesis in turbulent reactors subjects anoparticle aggregates to a homogeneous, time-varying shear flow. The shear flow results in anisotropic clusters and it is of interest to characterize the structural properties of these clusters and their effects on initiation and acceleration of aggregation, the restructuring of clusters, and their breakage. The anisotropic structure of a sheared cluster is characterized by the ratio of the major to minor axis length of the approximating ellipsoid oriented along the cluster moment of inertia tensor's principal ...
Physical review. E, Statistical, nonlinear, and soft matter physics, 2014
Aggregation of colloidal particles under shear is studied in model systems using a Langevin dynam... more Aggregation of colloidal particles under shear is studied in model systems using a Langevin dynamics model with an improved interparticle interaction potential. In the absence of shear, aggregates that form are characterized by compact structure at small scales and ramified structure at larger scales. This confirms the structural crossover mechanism previously suggested by Sorensen and coworkers, that colloidal aggregation occurs due to monomer addition at small scales and due to cluster-cluster aggregation at large scales. The fractal dimension of nonsheared aggregates is scale-dependent. Smaller aggregates have a higher fractal dimension than larger ones, but the radius of gyration where this crossover occurs is independent of potential well depth for sufficiently deep wells. When these aggregates are subjected to shear they become anisotropic and form extended cigar-like structures. The size of sheared anisotropic aggregates in the direction perpendicular to the shear flow is lim...
Intense electrical arcs were applied to thermoplastic (polyamide 66) and thermoset (fiber reinfor... more Intense electrical arcs were applied to thermoplastic (polyamide 66) and thermoset (fiber reinforced laminated polyester) materials and the resulting carbonization/metallization process was studied on a sub-micron scale with atomic force microscopy to understand very initial stage of reorganization of surface morphology. These changes can be critical in dramatic changes in surface resistivity preceding electric breakthrough. The surface microroughness and the localization of micro- and nanoparticles at the center (arc initiation area) and along the edges of the samples were significantly different for different arc regimes. We suggested that for thermoset, the material is pulled out of the surface in the arc formation area (the center of sample). Afterwards, the intensive re-deposition occurred along the edges enhancing non-uniform ablation around the arc initiation area. In contrary, for thermoplastic samples, the entire polymer surface was re-melted that resulted in dramatic smoothing of the initially non-uniform surface morphology.
Nanoscale uniform films containing gold nanoparticle and polyelectrolyte multilayer structures we... more Nanoscale uniform films containing gold nanoparticle and polyelectrolyte multilayer structures were fabricated by the using spin-assembly or spin-assisted layer-by-layer (SA-LbL) deposition technique. These SA-LbL films with a general formula [Au/(PAH-PSS)nPAH]m possessed a well-organized microstructure with uniform surface morphology and high surface quality at a large scale (tens of micrometers across). Plasmon resonance peaks from isolated nanoparticles and interparticle interactions were revealed in the UV-visible extinction spectra of the SA-LbL films. All films showed the strong extinction peak in the region of 510-550 nm, which is due to the plasmon resonance of the individual gold nanoparticles redshifted because of a local dielectric environment. For films with sufficient density of gold nanoparticles within the layers, the second strong peak was consistently observed between 620 and 660 nm, which is the collective plasmon resonance from intralayer interparticle coupling. Finally, we suggested that, for certain film designs, interlayer interparticle resonance might be revealed as an independent contribution at 800 nm in UV-visible spectra. The observation of independent and concurrent individual, intralayer, and interlayer plasmon resonances can be critical for sensing applications, which involve monitoring of optomechanical properties of ultrathin optically active compliant membranes.
Bulletin of the American Physical Society, Nov 20, 2005
Brownian Dynamics (BD) is an attractive approach to simulate solute nanoparticles in a suspension... more Brownian Dynamics (BD) is an attractive approach to simulate solute nanoparticles in a suspension of solvent molecules because it exploits the separation of time scales between solvent and solute dynamics to avoid explicit representation of the solvent molecules. In BD a nanoparticle's velocity evolves because of interaction with other nanoparticles through a systematic pairwise interaction force, while the effect of the solvent molecules on the nanoparticles is represented by a combination of frictional and random forces (Langevin part). This Langevin equation for the velocity is ...
Light-scattering data for the aggregation of colloidal nanoparticles shows that hybrid aggregates... more Light-scattering data for the aggregation of colloidal nanoparticles shows that hybrid aggregates with two different fractal dimensions can be formed depending on the magnitude and duration of the applied shear (CM Sorensen's group, Kansas State University). Formation of such super-aggregate structures with D f= 2.55, and their reverting to D f= 1.8 depending on the shear condition is not completely explained yet. Simulations can provide insight into this behavior, provided they can accurately capture the essential aggregation ...
Bulletin of the American Physical Society, Nov 24, 2008
Aggregation of nanoparticles in liquid suspension is a phenomenon that affects the design and sca... more Aggregation of nanoparticles in liquid suspension is a phenomenon that affects the design and scale-up of process equipment for nanoparticle synthesis. The radial distribution function of nanoparticle pairs is an essential statistic characterizing multiparticle dynamics that must be captured by Brownian dynamics (BD) simulations in order to accurately simulate the structure of nanoparticle aggregates. Molecular dynamics (MD) simulations of a model aggregating system are used as a benchmark to evaluate the simplest specification of the potential of mean force (PMF) in ...
Bulletin of the American Physical Society, Nov 23, 2009
Nanoparticle synthesis in turbulent reactors subjects anoparticle aggregates to a homogeneous, ti... more Nanoparticle synthesis in turbulent reactors subjects anoparticle aggregates to a homogeneous, time-varying shear flow. The shear flow results in anisotropic clusters and it is of interest to characterize the structural properties of these clusters and their effects on initiation and acceleration of aggregation, the restructuring of clusters, and their breakage. The anisotropic structure of a sheared cluster is characterized by the ratio of the major to minor axis length of the approximating ellipsoid oriented along the cluster moment of inertia tensor's principal ...
ABSTRACT Freely suspended gold nanoparticle arrays have been fabricated by encapsulation into lay... more ABSTRACT Freely suspended gold nanoparticle arrays have been fabricated by encapsulation into layer-by-layer nanomembranes. Such nanomembranes (see Figure) retain outstanding micromechanical properties and have an anisotropic mechanical response due to the uniformly oriented nanoparticle-containing stripes. Periodic variation of the Raman scattering across the microarrays is displayed (inset).
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Papers by Sergiy Markutsya