Image analysis and kinetics of aggregation

Roussel, Jean-François; Camoin, C.; Blanc, Robert

doi:10.1051/jphys:0198900500210325900

Cited by 8 publications

(4 citation statements)

References 3 publications

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“…The "two-dimensional" systems served as models for the investigation of general aspects of growth, [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] structure formation, [18][19][20][21][22][23][24] phase transitions, 25 and surface thermodynamics. [25][26][27][28][29] In other cases, the investigations focused on the practical applications such as thin-layer preparation [30][31][32][33][34][35]20 and particle characterization.…”

Section: Introductionmentioning

confidence: 99%

“…The “two-dimensional” systems served as models for the investigation of general aspects of growth, − structure formation, − phase transitions, and surface thermodynamics. − In other cases, the investigations focused on the practical applications such as thin-layer preparation − , and particle characterization. − The interfacial colloids may also have significant importance in well-known technologies such as froth flotation. − …”

Section: Introductionmentioning

confidence: 99%

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Evidence for Secondary Minimum Flocculation of Stöber Silica Nanoparticles at the Air−Water Interface: Film Balance Investigations and Computer Simulations

et al. 2003

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The interactions of Sto ¨ber silica nanospheres having diameters of ca. 40, 100, and 200 nm were studied at the water-air interface with a Wilhelmy film balance. The particle sizes and size distribution functions were determined from TEM measurements. According to in situ Brewster angle microscopy investigations and the calculated DLVO interparticle energies, the particles formed weakly cohesive films at the interface; hence, the increasing surface pressure during the compression was attributed to interparticle repulsion. The repulsion energies that were determined from the surface pressure versus surface area isotherms exceeded the calculated DLVO energies by 2-3 orders of magnitude. The extremely high interparticle repulsion was attributed to dipole-dipole interactions. Despite the high interparticle repulsion, the monolayer of the particles was in a weakly cohesive state prior to compression that was attributed to the recently recognized long-range attractions of capillary and electrostatic origin. The particle size dependent particle-particle (p-p) distances at the secondary energy minimum of total pair-interaction versus p-p distances curve were also interpreted in terms of the newly recognized interactions. A computer simulation-assisted method was proposed to estimate the error of assuming a hexagonal array of monodisperse particles, which was then taken into account in the calculation of the p-p distances determined from the pressure-area isotherms.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evidence for Secondary Minimum Flocculation of Stöber Silica Nanoparticles at the Air−Water Interface: Film Balance Investigations and Computer Simulations

et al. 2003

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“…Colloidal particles at liquid−fluid interfaces have significant roles in several important technologies, including oil recovery, − flotation, , (anti)foaming, − and waste-water treatments . They have also been used as models for two-dimensional growth, − phase transition, and interfacial thermodynamics. − ,− Significantly, generation of metallic and semiconductor particles and particulate films at aqueous solution−air interfaces has provided an entry to advanced materials. − Investigation of the formation and characterization of these systems with increasing vigor is, therefore, hardly surprising.…”

Section: Introductionmentioning

confidence: 99%

Monoparticulate Layers of Silanized Glass Spheres at the Water−Air Interface: Particle−Particle and Particle−Subphase Interactions

1996

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Silanization has rendered spherical (75 ± 5 μm diameter) glass particles to be weakly (sample A, ϑ = 55°), moderately (sample B, ϑ = 72°), and highly (sample C, ϑ = 90°) hydrophobic. Nonequilibrium surface pressure (Π) vs surface area (A) isotherms have been determined for monoparticulate layers which were prepared from samples A, B, and C at water−air interfaces in a Langmuir film balance. The effect of hydrophobicity on the particle−particle interaction and on the energy (E r) which is necessary for the removal of a particle from the water−air interface (particle−subphase interaction) has been elucidated. Contact cross-sectional areas (CCSA), surface coverages (SC), and collapse energies (E c), evaluated from Π vs A isotherms, provided semiquantitative information on the structural strength. Monoparticulate layers which were formed from the most hydrophobic glass spheres (sample C) had a structural strength which was almost 5 times greater than that of those which were formed from the least hydrophobic sample (sample A), as revealed by the E c values which were elucidated for these systems. Long-term stability, determined by time-dependent surface-pressure measurements, was only found for sample C. The energy of a particle−particle contact was calculated, for the strongly cohesive layer of sample C, to be (1.2−1.4) × 10-10 J. The weakly cohesive layer, prepared from sample A, had a 490-nm interparticle distance at the secondary energy minimum and a total repulsive interaction energy in the range of (0.5−1.3) × 10-13 J between two beads at an interparticle distance of 1−200 nm. Values for adhesion work (W r) were calculated from in situ contact-angle measurements and compared to corresponding E r values which were obtained experimentally by the isotherms. The significant discrepancies between the W r and E r values which were found for sample A or sample B were rationalized in terms of contact-angle hysteresis, dynamic wetting, and distortion of the electric double layer around the interfacial beads.

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“…The study of solid particulate associations at liquid-fluid interfaces attracted significant attention in the last two decades. The 2D systems served as models for the investigation of general aspects of growth, − particle ordering, phase transitions, and surface thermodynamics. − In other cases, the examinations focused on the practical applications such as thin layer preparation by a two-dimensional sol−gel technique − and characterizations of surface properties of particles. − …”

Section: Introductionmentioning

confidence: 99%

Two-Dimensional Aggregation of Rod-Like Particles: A Model Investigation

et al. 2002

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In this work, a 2D computer model was created for the aggregation of rodlike particles, on the basis of a molecular-dynamic approach. With the help of the model, it is possible to visualize the motion of the aggregating particles, clearly and faithfully, offering the possibility of structural, kinetic, and dynamic analysis of the aggregation. The aggregation, in the model, is governed by long-range and short-range attractive particleparticle forces, two-dimensional streams, breaking forces, and the degree of particle-anisometry. The longrange forces initiate the motions of the particles and clusters and also cause restructuring in the growing aggregates, which process can be hindered by sufficiently strong short-range, attractive forces. The offlattice computer simulation of the aggregation revealed that (i) the greater extent of restructuring resulted in the formation of denser and more compact clusters with higher fractal dimensions. Interestingly, the attractive short-range forces, through the restructuring, could also influence the driving force of aggregation. It was found that the more intensive the restructuring, the weaker the driving force is in the second stage of aggregation. (ii) An increase in the effective range of long-range forces (without restructuring) resulted in higher fractal dimensions and kinetic constants. The increase of D f with the effective range of forces was interpreted in terms of a percolation-like aggregation. (iii) Moreover, increasing anisometry of the particles (without restructuring) also resulted in an increase of fractal dimensions, confirming that the investigated aggregations take place in a transition range between the diffusion-limited-like aggregation and percolation (gelation). Our model was implemented successfully in a real phenomenon, the aggregation of cylindrical-shaped carbon particles at water (aqueous surfactant solution)/air interfaces. The effectiveness of the computer model was proved by comparing the structural, kinetics, and mechanism-related parameters obtained for the simulations with those of the real experiments.

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Image analysis and kinetics of aggregation

Cited by 8 publications

References 3 publications

Evidence for Secondary Minimum Flocculation of Stöber Silica Nanoparticles at the Air−Water Interface: Film Balance Investigations and Computer Simulations

Evidence for Secondary Minimum Flocculation of Stöber Silica Nanoparticles at the Air−Water Interface: Film Balance Investigations and Computer Simulations

Monoparticulate Layers of Silanized Glass Spheres at the Water−Air Interface: Particle−Particle and Particle−Subphase Interactions

Two-Dimensional Aggregation of Rod-Like Particles: A Model Investigation

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