Contact angle of micro- and nanoparticles at fluid interfaces

Maestro, Armando; Guzmán, Eduardo; Ortega, Francisco; Rubio, Ramón G.

doi:10.1016/j.cocis.2014.04.008

Cited by 144 publications

(165 citation statements)

References 88 publications

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“…• ± 6 • ) [44,42,43] The relaxation of the the sterically stabilized PMMA particles is much faster than that of polymer spheres dispersed in the aqueous phase. To understand this difference, we use the two dynamical models to infer the area and pinning energy per defect.…”

Section: Topographical Features On Polymer Particles Pin the Contact mentioning

confidence: 99%

Contact-line pinning controls how quickly colloidal particles equilibrate with liquid interfaces

et al. 2016

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Previous experiments have shown that spherical colloidal particles relax to equilibrium slowly after they adsorb to a liquid-liquid interface, despite the large interfacial energy gradient driving the adsorption. The slow relaxation has been explained in terms of transient pinning and depinning of the contact line on the surface of the particles. However, the nature of the pinning sites has not been investigated in detail. We use digital holographic microscopy to track a variety of colloidal spheres-inorganic and organic, charge-stabilized and sterically stabilized, aqueous and non-aqueous-as they breach liquid interfaces. We find that nearly all of these particles relax logarithmically in time over timescales much larger than those expected from viscous dissipation alone. By comparing our results to theoretical models of the pinning dynamics, we infer the area per defect to be on the order of a few square nanometers for each of the colloids we examine, whereas the energy per defect can vary from a few kT for non-aqueous and inorganic spheres to tens of kT for aqueous polymer particles. The results suggest that the likely pinning sites are topographical features inherent to colloidal particles-surface roughness in the case of silica particles and grafted polymer "hairs" in the case of polymer particles. We conclude that the slow relaxation must be taken into

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Section: Topographical Features On Polymer Particles Pin the Contact mentioning

confidence: 99%

Contact-line pinning controls how quickly colloidal particles equilibrate with liquid interfaces

et al. 2016

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“…1 A better understanding of these interfacial systems is crucial to shed light on complex physical processes like heterogeneous catalysis, 2 electron transfer, 3 biological surface activity, 4 biosensing 5 and self-assembly. 6 Understanding and controlling the adsorption of particles of dimensions below tens of nanometers at interfaces will help to design Pickering emulsions with longer stability, 6,7 to improve 2D supracrystals for catalytic applications with enhanced efficiency, 8,9 to stabilize self-assembled structures for surface-enhanced Raman spectroscopy detection of traces 10 and for nanoplasmonic applications.…”

Section: Introductionmentioning

confidence: 99%

Contact angle and adsorption energies of nanoparticles at the air–liquid interface determined by neutron reflectivity and molecular dynamics

et al. 2015

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Understanding how nanomaterials interact with interfaces is essential to control their self-assembly as well as their optical, electronic, and catalytic properties. We present here an experimental approach based on neutron reflectivity (NR) that allows the in situ measurement of the contact angles of nanoparticles adsorbed at fluid interfaces. Because our method provides a route to quantify the adsorption and interfacial energies of the nanoparticles in situ, it circumvents problems associated with existing indirect methods, which rely on the transport of the monolayers to substrates for further analysis. We illustrate the method by measuring the contact angle of hydrophilic and hydrophobic gold nanoparticles, coated with perdeuterated octanethiol (d-OT) and with a mixture of d-OT and mercaptohexanol (MHol), respectively.The contact angles were also calculated via atomistic molecular dynamics (MD) computations, showing excellent agreement with the experimental data. Our method opens the route to quantify the adsorption of complex nanoparticle structures adsorbed at fluid interfaces featuring different chemical compositions.

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“…4. According to the previous studies, the impaction angle of droplets onto the surface has a significant effect on deposition behavior of droplets [21]. The blow-by gases flow colliding with the intake valve's surface follows the curvature of valve chamber; therefore, the droplets in the blow-by gases impact the valve surface in different angles.…”

Section: Effective Parameters On Deposit Formationmentioning

confidence: 98%

Taguchi optimization of micron sized lubricant oil droplet deposition on a hot plate

et al. 2015

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The deposition of micron sized lubricant oil droplets similar to oil droplets in blow-by gases of Internal combustion (IC) engines on a hot flat plate was studied using a round impinging jet configuration. Five parameters which simulate the different operational conditions in IC engines were chosen: The impaction nozzle's outlet diameter, additional air flow rate, plate angle, plate temperature, and nozzle to the plate distance. An Experimental test-rig was constructed to acquire deposit weight with different parameter values. To find the conditions of minimum deposition, the deposit's weight was optimized using the Taguchi design of experiment method with respect to the design parameters. Using the experimental data, the predicted optimal value of the deposit weight was confirmed. Analysis of variance showed that plate angle is the most influential factor in deposition of fine oil droplets. Scanning electron microscopy (SEM) was used to investigate the mechanism of deposition.

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Contact angle of micro- and nanoparticles at fluid interfaces

Cited by 144 publications

References 88 publications

Contact-line pinning controls how quickly colloidal particles equilibrate with liquid interfaces

Contact-line pinning controls how quickly colloidal particles equilibrate with liquid interfaces

Contact angle and adsorption energies of nanoparticles at the air–liquid interface determined by neutron reflectivity and molecular dynamics

Taguchi optimization of micron sized lubricant oil droplet deposition on a hot plate

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