scholarly journals Investigation of Single and Binary of “Sandwich” Type Convex Liquid Capillary Bridges, Stretched between Two Flat Surfaces (Experimental Approach)

2019 ◽  
Vol 3 (4) ◽  
pp. 68 ◽  
Author(s):  
Plamen V. Petkov ◽  
Boryan Radoev

The interest to monophasic liquid capillary bridges (CB) has a long history. These shapes are attractive not only because of their interesting surface properties but also because of the possibility of their behavior to be analytically predicted by the equations of differential geometry. In the current paper we extend our previous studies by implementation of an approach for prediction of liquid gravityless CB behavior during their quasi-static stretching. It was found, that a simple linear relation, h r m ~ ln R r m , is valid the case of good wetting, 0° ≤ θ ≤ 90°, where h is the height of CB, R is the radius at the contact surface, rm is the CB waist radius, and θ is the solid/liquid (static, receding) contact angle. We experimentally studied the geometrical properties evolution of monophasic cedar oil and water CBs between two glass plates during their quasi-static (stepwise with equilibration after each step for 1–2 min.) stretching. In addition, we investigated a binary CB of a new type, resembling “sandwich”. There, due to the stronger glass wetting by the water, the oil phase is adhered at the water/gas interface, partially engulfed with a tendency to stand in the zone around the waist (minimal surface energy). During the stretching, it tends to replace the water in the CB waist region. A simple mechanism for interaction of the two immiscible liquids leading to creation of “sandwich” like binary structures, is proposed. Experiments of capillary bridges (CB) stretching between two flat surfaces have been carried for all liquids at different volume proportions. The investigation is extended also to identification of CB profile generatrix shape. We experimentally found that for monophasic CB, it can be described by a circle during the quasi-static stretching. If the CB height is increased, before the rupture, the shape evolves consecutively to an ellipse, parabola, or possibly to a hyperbola. The investigated binary CB evolves a similar way. Conclusions are drawn and directions for further investigations are given.

1998 ◽  
Vol 518 ◽  
Author(s):  
Sang-Ho Lee ◽  
Myong-Jong Kwon ◽  
Jin-Goo Park ◽  
Yong-Kweon Kim ◽  
Hyung-Jae Shin

AbstractHighly hydrophobic fluorocarbon films were prepared by the vapor phase (VP) deposition method in a vacuum chamber using both liquid (3M's FC40, FC722) and solid sources (perfluorodecanoic acid (CF3(CF2)8COOH), perfluorododecane (C12F26)) on Al, Si and oxide coated wafers. The highest static contact angles of water were measured on films deposited on aluminum substrate. But relatively lower contact angles were obtained on the films on Si and oxide wafers. The advancing and receding contact angle analysis using a captive drop method showed a large contact angle hysteresis (ΔH) on the VP deposited fluorocarbon films. AFM study showed poor film coverage on the surface with large hysteresis. FTIR-ATR analysis positively revealed the stretching band of CF2 groups on the VP deposited substrates. The thermal stability of films was measured at 150°C in air and nitrogen atmospheres as a function of time. The rapid decrease of contact angles was observed on VP deposited FC and PFDA films in air. However, no decrease of contact angle on them was observed in N2.


2020 ◽  
Vol 161 ◽  
pp. 01062
Author(s):  
K.R. Tarantseva ◽  
M.I. Yakhkind ◽  
A.K. Mishra ◽  
M.A. Marynova ◽  
E.A. Polyanskova ◽  
...  

Systems of two immiscible liquids are proposed for a new type of membraneless fuel cells using renewable fuel, in which the stationary phase boundary carries out a role of membrane. These systems consist of water, alcohol (preferable ethanol) and a number of electrolytes (salts and bases) leading to the layering of aqueous alcohol. In such systems top phase has significant alcohol content and insignificant electrolyte content, bottom phase has significant electrolyte content and insignificant alcohol content. To study the layering conditions in these systems, binodal curves were plotted for three two-phase liquid systems (EtOH + K2CO3 + H2O; EtOH + K3PO4 + H2O, EtOH + KOH + H2O), using the cloud point method. Comparison of our experimental data with the results of other authors showed that they are consistent for the first and second systems, and the temperature dependence of the binodal curves is clearly visible for the third system. The specific system EtOH – 30 % m/m; KOH – 40 % m/m; H2O – 30 % m/m was taken as the basis for studies of fuel cells based on two immiscible liquids. A further area of research lies in the field of optimizing the composition of both phases, studying the processes of mass transfer in these systems and their physicochemical characteristics.


Author(s):  
Carmen L. Moraila-Martínez ◽  
Francisco J. Montes Ruiz-Cabello ◽  
Miguel A. Cabrerizo-Vílchez ◽  
Miguel A. Rodríguez-Valverde

Author(s):  
Giulio Croce ◽  
Paola D’Agaro ◽  
Nicola Suzzi

Abstract A langrangian-based phenomenological model, following the evolution of the individual droplets nucleating at random positions, is applied to the simulation and optimization of hybrid, mixed hydrophobic and hydrophilic surfaces. The proposed mathematical model was originally developed to simulate droplets pattern evolution in the framework of in-flight icing problems and takes into account the surface tension effects (via the advancing and receding contact angle values), the external force balance on the single droplets, as well as the both the condensing and coalescence process. Here, the model is extended to the case of an arbitrary curved substrate surface and a parametric analysis of different cases is carried out, looking for the parameters that help to identify the optimal design for a given set of wettability properties, nucleation site density and wet surface condensation rates. A discussion on the sensitivity of the solutions with respect to the expected high uncertainties on the estimate of some of these parameters in actual practical problems is also presented, in order to assess the effectiveness of the simulation as a design tool. The analysis is carried out for condensation enhancement on both plane surfaces and mini or micro tubes. Comparison with experimental, open literature data ensure the reliability of the approach for both geometries.


2019 ◽  
Vol 9 (3) ◽  
pp. 20180074 ◽  
Author(s):  
Giuliana Giunta ◽  
Paola Carbone

Using molecular dynamics simulations, we analysed the polymer dynamics of chains of different molecular weights entrapped at the interface between two immiscible liquids. We showed that on increasing the viscosity of one of the two liquids the dynamic behaviour of the chain changes from a Zimm-like dynamics typical of dilute polymer solutions to a Rouse-like dynamics where hydrodynamic interactions are screened. We observed that when the polymer is in contact with a high viscosity liquid, the number of solvent molecules close to the polymer beads is reduced and ascribed the screening effect to this reduced number of polymer–solvent contacts. For the longest chain simulated, we calculated the distribution of loop length and compared the results with the theoretical distribution developed for solid/liquid interfaces. We showed that the polymer tends to form loops (although flat against the interface) and that the theory works reasonably well also for liquid/liquid interfaces.


1996 ◽  
Vol 67 (8) ◽  
pp. 2852-2858 ◽  
Author(s):  
Shi‐Yow Lin ◽  
Hong‐Chi Chang ◽  
Lung‐Wei Lin ◽  
Pao‐Yao Huang

Langmuir ◽  
1999 ◽  
Vol 15 (21) ◽  
pp. 7378-7385 ◽  
Author(s):  
H. Yildirim Erbil ◽  
G. McHale ◽  
S. M. Rowan ◽  
M. I. Newton

Langmuir ◽  
2014 ◽  
Vol 30 (31) ◽  
pp. 9346-9354 ◽  
Author(s):  
Paola G. Pittoni ◽  
Chia-Hui Lin ◽  
Teng-Shiang Yu ◽  
Shi-Yow Lin

Sign in / Sign up

Export Citation Format

Share Document