scholarly journals Size dependent influence of contact line pinning on wetting of nano-textured/patterned silica surfaces

Nanoscale ◽  
2020 ◽  
Vol 12 (41) ◽  
pp. 21376-21391
Author(s):  
H. Gokberk Ozcelik ◽  
Ezgi Satiroglu ◽  
Murat Barisik
Keyword(s):  
Contact Line ◽  
Size Ratio ◽  
Surface Pattern ◽  
Silica Surfaces ◽  
Size Dependent ◽  
Contact Line Pinning

A wetting similarity develops as a function of size ratio between the droplet and surface pattern under pinning effects independent of wetting.

Droplet spreading and absorption on rough, permeable substrates

2015 ◽  
Vol 784 ◽  
pp. 465-486 ◽  
Author(s):  
Leonardo Espín ◽  
Satish Kumar
Keyword(s):  
Surface Roughness ◽  
Contact Line ◽  
Nonlinear Evolution ◽  
Precursor Film ◽  
Radial Coordinate ◽  
Droplet Spreading ◽  
Liquid Spreading ◽  
Line Region ◽  
Influence Of Substrate ◽  
Contact Line Pinning

Wetting of permeable substrates by liquids is an important phenomenon in many natural and industrial processes. Substrate heterogeneities may significantly alter liquid spreading and interface shapes, which in turn may alter liquid imbibition. A new lubrication-theory-based model for droplet spreading on permeable substrates that incorporates surface roughness is developed in this work. The substrate is assumed to be saturated with liquid, and the contact-line region is described by including a precursor film and disjoining pressure. A novel boundary condition for liquid imbibition is applied that eliminates the need for a droplet-thickness-dependent substrate permeability that has been employed in previous models. A nonlinear evolution equation describing droplet height as a function of time and the radial coordinate is derived and then numerically solved to characterize the influence of substrate permeability and roughness on axisymmetric droplet spreading. Because it incorporates surface roughness, the new model is able to describe the contact-line pinning that has been observed in experiments but not captured by previous models.

Anomalous Contact Angle Hysteresis of a Captive Bubble: Advancing Contact Line Pinning

Langmuir ◽  
2011 ◽  
Vol 27 (11) ◽  
pp. 6890-6896 ◽  
Author(s):  
Siang-Jie Hong ◽  
Feng-Ming Chang ◽  
Tung-He Chou ◽  
Seong Heng Chan ◽  
Yu-Jane Sheng ◽  
...  
Keyword(s):  
Contact Angle ◽  
Contact Line ◽  
Contact Angle Hysteresis ◽  
Contact Line Pinning

Contact Line Pinning Effects Influence Determination of the Line Tension of Droplets Adsorbed on Substrates

2018 ◽  
Vol 122 (30) ◽  
pp. 17184-17189 ◽  
Author(s):  
Hongguang Zhang ◽  
Shan Chen ◽  
Zhenjiang Guo ◽  
Yawei Liu ◽  
Fernando Bresme ◽  
...  
Keyword(s):  
Contact Line ◽  
Line Tension ◽  
Contact Line Pinning

scholarly journals Contact Line Pinning Is Not Required for Nanobubble Stability on Copolymer Brushes

2018 ◽  
Vol 9 (15) ◽  
pp. 4239-4244 ◽  
Author(s):  
David S. Bull ◽  
Nathaniel Nelson ◽  
Danielle Konetski ◽  
Christopher N. Bowman ◽  
Daniel K. Schwartz ◽  
...  
Keyword(s):  
Contact Line ◽  
Copolymer Brushes ◽  
Contact Line Pinning

Contact Line Pinning and Depinning Prior to Rupture of an Evaporating Droplet in a Simulated Soil Pore

2020 ◽  
Author(s):  
Partha P. Chakraborty ◽  
Melanie M. Derby
Keyword(s):  
Contact Line ◽  
Pressure Difference ◽  
Liquid Droplet ◽  
Liquid Droplets ◽  
Water Contact ◽  
Marginal Rate ◽  
Vapor Interface ◽  
Hydrophobic Pore ◽  
Contact Line Pinning ◽  
Liquid Vapor

Abstract Altering soil wettability by inclusion of hydrophobicity could be an effective way to restrict evaporation from soil, thereby conserving water resources. In this study, 4-μL sessile water droplets were evaporated from an artificial soil millipore comprised of three glass (i.e. hydrophilic) and Teflon (i.e. hydrophobic) 2.38-mm-diameter beads. The distance between the beads were kept constant (i.e. center-to-center spacing of 3.1 mm). Experiments were conducted in an environmental chamber at an air temperature of 20°C and 30% and 75% relative humidity (RH). Evaporation rates were faster (i.e. ∼19 minutes and ∼49 minutes at 30% and 75% RH) from hydrophilic pores than the Teflon one (i.e. ∼24 minutes and ∼52 minutes at 30% and 75% RH) due in part to greater air-water contact area. Rupture of liquid droplets during evaporation was analyzed and predictions were made on rupture based on contact line pinning and depinning, projected surface area just before rupture, and pressure difference across liquid-vapor interface. It was observed that, in hydrophilic pore, the liquid droplet was pinned on one bead and the contact line on the other beads continuously decreased by deforming the liquid-vapor interface, though all three gas-liquid-solid contact lines decreased at a marginal rate in hydrophobic pore. For hydrophilic and hydrophobic pores, approximately 1.7 mm2 and 1.8–2 mm2 projected area of the droplet was predicted at 30% and 75% RH just before rupture occurs. Associated pressure difference responsible for rupture was estimated based on the deformation of curvature of liquid-vapor interface.

scholarly journals On-demand contact line pinning during droplet evaporation

2020 ◽  
Vol 312 ◽  
pp. 127983
Author(s):  
Wei Wang ◽  
Qi Wang ◽  
Kaidi Zhang ◽  
Xubo Wang ◽  
Antoine Riaud ◽  
...  
Keyword(s):  
Contact Line ◽  
Droplet Evaporation ◽  
On Demand ◽  
Contact Line Pinning

Electric charge of nanopatterned silica surfaces

2019 ◽  
Vol 21 (14) ◽  
pp. 7576-7587 ◽  
Author(s):  
H. Gokberk Ozcelik ◽  
Murat Barisik
Keyword(s):  
Surface Charge ◽  
Flat Surface ◽  
Ionic Concentration ◽  
Surface Pattern ◽  
Surface Charges ◽  
Local Surface ◽  
Silica Surfaces ◽  
Pattern Size ◽  
Theoretical Predictions ◽  
Surface Patterns

The surface charge density of a nanopatterned silica decreased at the pits but increased at the tips of surface patterns. For a case of self-repeating surface structures, the average of local surface charges becomes lower than the theoretical predictions. Our phenomenological model developed as an extension to the existing flat surface theory predicts the average surface charge on a nanopatterned surface as a function of surface pattern size, ionic concentration and pH.

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