Temperature dependence of the contact angle at the polymer-water interface

1987 ◽  
Vol 116 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Soon Hong Yuk ◽  
Mu Shik Jhon
Keyword(s):  
Contact Angle ◽  
Temperature Dependence ◽  
Water Interface

Temperature Dependence of the Air/Water Interface Revealed by Polarization Sensitive Sum-Frequency Generation Spectroscopy

2018 ◽  
Author(s):  
Daniel R. Moberg ◽  
Shelby C. Straight ◽  
Francesco Paesani
Keyword(s):  
Temperature Dependence ◽  
Low Frequency ◽  
Potential Energy Function ◽  
Md Simulations ◽  
Sum Frequency Generation ◽  
Water Molecules ◽  
Water Interface ◽  
Sum Frequency ◽  
Air Water Interface ◽  
Frequency Generation

<div> <div> <div> <p>The temperature dependence of the vibrational sum-frequency generation (vSFG) spectra of the the air/water interface is investigated using many-body molecular dynamics (MB-MD) simulations performed with the MB-pol potential energy function. The total vSFG spectra calculated for different polarization combinations are then analyzed in terms of molecular auto-correlation and cross-correlation contributions. To provide molecular-level insights into interfacial hydrogen-bonding topologies, which give rise to specific spectroscopic features, the vSFG spectra are further investigated by separating contributions associated with water molecules donating 0, 1, or 2 hydrogen bonds to neighboring water molecules. This analysis suggests that the low frequency shoulder of the free OH peak which appears at ∼3600 cm−1 is primarily due to intermolecular couplings between both singly and doubly hydrogen-bonded molecules. </p> </div> </div> </div>

Temperature Dependence of Sessile Bubble Contact Angle at a Water–Silicon Interface

2020 ◽  
Vol 82 (5) ◽  
pp. 522-528
Author(s):  
N. E. Esipova ◽  
A. I. Rusanov ◽  
V. D. Sobolev
Keyword(s):  
Contact Angle ◽  
Temperature Dependence ◽  
Silicon Interface

scholarly journals Air-entrapping capacity in the hair coverage of Malacosoma castrensis (Lasiocampidae: Lepidoptera) caterpillar: a case study

2020 ◽  
Vol 223 (14) ◽  
pp. jeb225029
Author(s):  
Alexander Kovalev ◽  
Manuela Rebora ◽  
Gianandrea Salerno ◽  
Stanislav Gorb
Keyword(s):  
Contact Angle ◽  
Salt Marshes ◽  
Support Pressure ◽  
Water Repellent ◽  
Water Interface ◽  
Tracheal System ◽  
Effective Contact ◽  
Water Percolation ◽  
Side Walls ◽  
The Stability

ABSTRACTThe moth Malacosoma castrensis (Lasiocampidae) is commonly found along the Northern Germany coasts, the habitats of which are mainly represented by salt marshes subjected to sea level variations. Surprisingly, terrestrial caterpillars can withstand many hours of being flooded by seawater. The ability to withstand periods of submersion in a terrestrial insect raises the problem of respiration related to avoiding water percolation into the tracheal system. In the present study, we investigated under laboratory conditions the role of water-repellent cuticle structures in oxygen supply in caterpillars of M. castrensis submerged in water. For this purpose, air-layer stability tests using force measurements, and micromorphology of cuticle structures using SEM and fluorescence microscopy, were performed. A plastron appeared when a caterpillar is underwater. The stability, gas composition and internal pressure of the plastron were estimated. The plastron is stabilized by long and scarce hairs, which are much thicker than the corresponding hairs of aquatic insects. Thick and stiff hairs with sclerotized basal and middle regions protrude into the water through the plastron–water interface, while substantial regions of thin and flexible hairs are aligned along the plastron–water interface and their side walls can support pressure in the plastron even below atmospheric pressure. Additional anchoring points between hair's stalk and microtrichia near the hair base provide enhanced stiffness to the hair layer and prevent the hair layer from collapse and water entering between hairs. The advancing contact angle on hairs is more than 90 deg, which is close to the effective contact angle for the whole caterpillar.

scholarly journals A Complete experimental study of oil/water interfacial properties in the presence of TiO2 nanoparticles and different ions

2019 ◽  
Vol 74 ◽  
pp. 39 ◽  
Author(s):  
Ali Khalilnezhad ◽  
Hosein Rezvani ◽  
Parastoo Ganji ◽  
Yousef Kazemzadeh
Keyword(s):  
Contact Angle ◽  
Zeta Potential ◽  
Interfacial Properties ◽  
Optimum Concentration ◽  
Viscosity Reduction ◽  
Wettability Alteration ◽  
Batch Adsorption ◽  
Water Interface ◽  
Oil Viscosity ◽  
Oil Water

Previous studies on Nanoparticles (NPs) application for Enhanced Oil Recovery (EOR) methods have revealed their effective role in the rock wettability alteration, relative Interfacial Tension (IFT) and oil viscosity reduction, formation and stabilization of the emulsions, and reduced asphaltene precipitation, which are all in direct relationship with oil/water interfacial properties. This study focuses on the interfacial properties of oil/water in the presence of Titania NPs and different ions at different pressures and temperatures. For this, different concentrations of TiO2 NPs in the Formation Water (FW) were prepared to monitor the effects of NPs on the oil/water IFT, carbonate rock wettability, zeta potential, and asphaltene adsorption. The results on IFT values indicated that NPs behavior at high pressures and temperatures is completely different, as compared to the ambient conditions, and 1000 ppm NPs introduced the lowest IFT at 600 psi and 60 °C. This reduction is potentially attributed to the asphaltene adsorption at the oil/water interface by TiO2 NPs, which hinders the asphaltene deposition at the interface and in turn IFT increasing. Contact angle results revealed two distinctive behaviors for NPs at high and low concentrations. In other words, with the first interval (below the optimum concentration), an increase in NPs concentration led to a quick wettability alteration toward the water-wet condition, and with the second one (above the optimum concentration), there was an increase in contact angle with an increase in NPs concentration, which is due to the NPs stacking near the rock surface. These results were in good accordance with zeta potential measurements, in which 1000 ppm nanofluid presented the highest stability (zeta potential value of −46.9 mV). Batch adsorption experiments resulted that catalytic TiO2 NPs are capable of adsorbing asphaltene at the oil/water interface. In addition, the results on fitting experimental data to the Langmuir and Freundlich Isotherms showed that the adsorption best fitted Langmuir Isotherm and hence the adsorption type is a monolayer.

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