Retention of liquid drops by solid surfaces

Extrand, C. W.; Gent, A. N.

doi:10.1016/0021-9797(90)90225-d

Cited by 188 publications

(193 citation statements)

References 12 publications

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“…An analogous result is given by Extrand and Gent (1990) for the retention of liquid drops on solid surfaces. Using mean values for the contact area A (27500·µm 2 ) and an estimate of 30·mN·m -1 for the surface tension γL of a mainly hydrophobic secretion (Israelachvili, 1992), we obtain: F << 8RγL ≈ 22 µN (corresponding to approx.…”

Section: Possible In-plane Contribution Of Surface Tensionmentioning

confidence: 54%

Biomechanics of ant adhesive pads: frictional forces are rate- and temperature-dependent

Federle

Baumgärtner

Hölldobler

2004

Journal of Experimental Biology

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Tarsal adhesive pads enable insects to hold on to smooth plant surfaces. Using a centrifuge technique, we tested whether a 'wet adhesion' model of a thin film of liquid secreted between the pad and the surface can explain adhesive and frictional forces in Asian Weaver ants (Oecophylla smaragdina).When forces are acting parallel to the surface, pads in contact with the surface can slide smoothly. Force per unit pad contact area was strongly dependent on sliding velocity and temperature. Seemingly consistent with the effect of a thin liquid film in the contact zone, (1) frictional force linearly increased with sliding velocity, (2) the increment was greater at lower temperatures and (3) no temperature dependence was detected for low-rate perpendicular detachment forces. However, we observed a strong, temperature-independent static friction that was inconsistent with a fully lubricated contact. Static friction was too large to be explained by the contribution of other (sclerotized) body parts. Moreover, the rate-specific increase of shear stress strongly exceeded predictions derived from estimates of the adhesive liquid film's thickness and viscosity.Both lines of evidence indicate that the adhesive secretion alone is insufficient to explain the observed forces and that direct interaction of the soft pad cuticle with the surface ('rubber friction') is involved.

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Section: Possible In-plane Contribution Of Surface Tensionmentioning

confidence: 54%

Biomechanics of ant adhesive pads: frictional forces are rate- and temperature-dependent

Federle

Baumgärtner

Hölldobler

2004

Journal of Experimental Biology

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“…Frenkel [12] arrived at a similar formula for contact line forces using energy methods. Later experimental studies have proposed various correction factors to these formulae [13][14][15][16][17]. A more basic approach to finding the retention force was adopted by ElSherbini and Jacobi [18][19][20] who studied sessile droplets on a slope both experimentally and theoretically.…”

Section: Introductionmentioning

confidence: 99%

Droplet retention on an incline

Annapragada¹,

Murthy

Garimella

2012

International Journal of Heat and Mass Transfer

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The present study seeks to understand and predict droplet retention on smooth hydrophobic surfaces. The droplet shape and the advancing and receding contact angles are experimentally measured as a function of droplet size under the action of a gravitational force at different inclination angles. The advancing and receding contact angles are correlated with static contact angle and Bond number. A Volume of Fluid -Continuous Surface Force model with varying contact angles along the triple contact line is developed to predict droplet shape. The model is first verified against a twodimensional analytical solution. It is then used to simulate the shape of a sessile droplet on an incline at various angles of inclination and to determine the critical angle of inclination as a function of droplet size. Good agreement is found between experimental measurements and predictions. The contact line profile and contact area are also predicted. The contact area predictions based on a spherical-cap assumption are compared to the numerical predictions and are found to underpredict the droplet contact area.

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“…as well as a lower bound, since the evaporation of a droplet on the substrate must be complete before the arrival of the next droplet, to avoid puddle formation, which would be detrimental to the generation of nanostructures and to out-of plane nanoprinting. 1,3,18 In this work we investigate charge transport in the nanodripping regime by printing nanoparticles dispersed in tetradecane, a solvent fulfilling all of the above-mentioned requirements. The electrical conductivity of tetradecane in its pure form was measured to be as low as 3 • 10 !!"…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4] Recently an electrohydrodynamic printing regime has been demonstrated in a rapid dripping mode (termed NanoDrip), where the ejected colloidal droplets from nozzles of diameters of O(1 µm) can controllably reach sizes an order of magnitude smaller than the nozzle and can generate planar and out-of-plane structures of similar sizes.1 Despite demonstrated capabilities, our fundamental understanding of important aspects of the physics of NanoDrip printing needs further improvement.Here we address the topics of charge content and transport in NanoDrip printing. We employ quantum dot and gold nanoparticle dispersions in combination with a specially designed, auxiliary, asymmetric electric field, targeting the understanding of charge locality (particles vs. solvent) and particle distribution in the deposits as indicated by the dried nanoparticle patterns (footprints) on the substrate.…”

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confidence: 99%

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Charge effects and nanoparticle pattern formation in electrohydrodynamic NanoDrip printing of colloids

et al. 2016

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Advancing open atmosphere printing technologies to produce features in the nanoscale range has important and broad applications ranging from electronics, to photonics, plasmonics and biology. [1][2][3][4] Recently an electrohydrodynamic printing regime has been demonstrated in a rapid dripping mode (termed NanoDrip), where the ejected colloidal droplets from nozzles of diameters of O(1 µm) can controllably reach sizes an order of magnitude smaller than the nozzle and can generate planar and out-of-plane structures of similar sizes.1 Despite demonstrated capabilities, our fundamental understanding of important aspects of the physics of NanoDrip printing needs further improvement.Here we address the topics of charge content and transport in NanoDrip printing. We employ quantum dot and gold nanoparticle dispersions in combination with a specially designed, auxiliary, asymmetric electric field, targeting the understanding of charge locality (particles vs. solvent) and particle distribution in the deposits as indicated by the dried nanoparticle patterns (footprints) on the substrate. We show that droplets of alternating charge can be spatially separated when applying an ac field to the nozzle. The nanoparticles within a droplet are distributed asymmetrically under the influence of the auxiliary lateral electric field, indicating that they are the main carriers. We alsoshow that the ligand length of the nanoparticles in the colloid affects their mobility after deposition (in the sessile droplet state).2

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Retention of liquid drops by solid surfaces

Cited by 188 publications

References 12 publications

Biomechanics of ant adhesive pads: frictional forces are rate- and temperature-dependent

Biomechanics of ant adhesive pads: frictional forces are rate- and temperature-dependent

Droplet retention on an incline

Charge effects and nanoparticle pattern formation in electrohydrodynamic NanoDrip printing of colloids

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