Journal Article10.1126/SCIENCE.256.5063.1539
How to make water run uphill.
TL;DR: A surface having a spatial gradient in its surface free energy was capable of causing drops of water placed on it to move uphill after an imbalance in the forces due to surface tension acting on the liquid-solid contact line on the two opposite sides of the drop.
read more
Abstract: A surface having a spatial gradient in its surface free energy was capable of causing drops of water placed on it to move uphill. This motion was the result of an imbalance in the forces due to surface tension acting on the liquid-solid contact line on the two opposite sides ("uphill" or "downhill") of the drop. The required gradient in surface free energy was generated on the surface of a polished silicon wafer by exposing it to the diffusing front of a vapor of decyltrichlorosilane, Cl(3)Si(CH(2))(9)CH(3). The resulting surface displayed a gradient of hydrophobicity (with the contact angle of water changing from 97 degrees to 25 degrees ) over a distance of 1 centimeter. When the wafer was tilted from the horizontal plane by 15 degrees , with the hydrophobic end lower than the hydrophilic, and a drop of water (1 to 2 microliters) was placed at the hydrophobic end, the drop moved toward the hydrophilic end with an average velocity of approximately 1 to 2 millimeters per second. In order for the drop to move, the hysteresis in contact angle on the surface had to be low (</=10 degrees ).
read more
Chat with Paper
AI Agents for this Paper
Find similar papers on Google Scholar, PubMed and Arxiv
Write a critical review of this paper
Analyze citations of this paper to find unaddressed research gaps
Citations
Dancing drops over vibrating substrates
TL;DR: In this article, Borcia et al. studied the motion of a liquid drop on a solid plate simultaneously submitted to horizontal and vertical harmonic vibrations, using a phase field model for describing static and dynamic contact angles.
8
Surface nanostructuring of biocompatible polymer for wettability control in MEMS
Kwok Siong Teh,Yen-Wen Lu +1 more
- 28 Jan 2008
TL;DR: In this paper, a low-potential method to control surface roughness of doped polypyrrole through redox-induced transformation in surface morphology was presented, where the electric potential of as-deposited doped pyrrole in aqueous sodium dodecylbenzene sulfonate (0.1M) from -0.6 to +1.5V was used.
8
Effects of air-side surface wettability on the performance of dehumidifying heat exchangers
Liping Liu
- 25 May 2011
TL;DR: In this article, a model for predicting the mass of retained condensate is proposed based on laminar filmwise condensation assumptions, and the model suggests that mass retention on a heat exchanger increases with latent heat transfer rate (Q l) and decreases with air-side Reynolds number (Re dh), which are also reflected by the experimental data.
8
Marangoni-induced actuation of miscible liquid droplets on an incline
TL;DR: In this paper, the authors investigated the self-propulsion of a droplet up an incline, confined on a polydimethylsiloxane (PDMS) channel rendered hydrophilic through combined oxygen plasma and polyvinylpyrrolidone (PVP) treatment.
8
References
•Book
Physical chemistry of surfaces
Arthur W. Adamson
- 01 Jan 1960
TL;DR: In this paper, the authors discuss the nature and properties of liquid interfaces, including the formation of a new phase, nucleation and crystal growth, and the contact angle of surfaces of solids.
12.2K
The motion of bubbles in a vertical temperature gradient
TL;DR: In this article, it has been demonstrated that small bubbles in pure liquids can be held stationary or driven downwards by means of a sufficiently strong negative temperature gradient in the vertical direction, due to the stresses resulting from the thermal variation of surface tension at the bubble surface.
1K
The migration of liquid drops in a vertical temperature gradient
TL;DR: In this article, experiments were conducted on liquid drops migrating in a vertical temperature gradient, and the thermocapillary contribution to the drop velocities was found to scale correctly with both the drop radius and the applied temperature gradient as predicted by Young et al.
104
Dynamics of spreading of a liquid drop across a surface chemical discontinuity
Thierry Ondarçuhu,M. Veyssie +1 more
TL;DR: Ondarçuhu and Veyssié as discussed by the authors proposed a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not.
29