Water condensation and transport on bioinspired triangular patterns with heterogeneous wettability at a low temperature

Desert beetles and cactus plants collect water from fog in arid regions. The desert beetle uses heterogeneous wettability to transport water to its mouth. A cactus uses conical spines which provide Laplace pressure gradient to transport water to its base. In this study, bioinspired triangular patterns with various wettability and different from the surrounding regions were investigated to transport condensed water from ambient air. A low temperature of 5°C was used to decrease saturated vapour pressure to promote water condensation. Results from this study can be used to enhance the performance of water collection systems. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology’.

Download Full-text

Optimization of bioinspired triangular patterns for water condensation and transport

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2019.0127 ◽

2019 ◽

Vol 377 (2150) ◽

pp. 20190127 ◽

Cited By ~ 12

Author(s):

Dong Song ◽

Bharat Bhushan

Keyword(s):

Relative Humidity ◽

Pressure Gradient ◽

Surface Temperature ◽

Dew Point ◽

Laplace Pressure ◽

Theme Issue ◽

Water Condensation ◽

Water Collection ◽

Condensed Water ◽

Droplet Condensation

Water condenses on a surface in ambient environment if the surface temperature is below the dew point. For water collection, droplets should be transported to storage before the condensed water evaporates. In this study, Laplace pressure gradient inspired by conical spines of cactus plants is used to facilitate the transport of water condensed in a triangular pattern to the storage. Droplet condensation, transportation and water collection rate within the bioinspired hydrophilic triangular patterns with various lengths and included angles, surrounded by superhydrophobic regions, were explored. The effect of relative humidity was also explored. This bioinspired technique can be used to develop efficient water collection systems. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 2)’.

Download Full-text

Molecular dynamics simulation of the structure of liquid rubidium along the saturated vapour-pressure curve

Journal of Physics F Metal Physics ◽

10.1088/0305-4608/10/12/004 ◽

1980 ◽

Vol 10 (12) ◽

pp. 2581-2594 ◽

Cited By ~ 53

Author(s):

M Tanaka

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulation ◽

Vapour Pressure ◽

Dynamics Simulation ◽

Pressure Curve ◽

Saturated Vapour Pressure ◽

Saturated Vapour ◽

Vapour Pressure Curve ◽

Structure Of Liquid

Download Full-text

An electronic analogue of the saturated vapour pressure curve of water

Journal of Scientific Instruments ◽

10.1088/0950-7671/33/11/309 ◽

1956 ◽

Vol 33 (11) ◽

pp. 436-438 ◽

Cited By ~ 4

Author(s):

R J Taylor

Keyword(s):

Vapour Pressure ◽

Pressure Curve ◽

Saturated Vapour Pressure ◽

Saturated Vapour ◽

Vapour Pressure Curve

Download Full-text

Determination of the saturated vapour pressure of solid antimony sulphide

Vacuum ◽

10.1016/0042-207x(71)91792-1 ◽

1971 ◽

Vol 21 (11) ◽

pp. 574

Keyword(s):

Vapour Pressure ◽

Saturated Vapour Pressure ◽

Saturated Vapour

Download Full-text

Raoult’s law revisited: accurately predicting equilibrium relative humidity points for humidity control experiments

10.1101/089094 ◽

2016 ◽

Author(s):

Michael G. Bowler ◽

David R. Bowler ◽

Matthew W. Bowler

Keyword(s):

Relative Humidity ◽

Vapour Pressure ◽

Control Device ◽

Raoult’S Law ◽

Simple Argument ◽

Humidity Control ◽

Saturated Vapour Pressure ◽

Saturated Vapour ◽

Equilibrium Relative Humidity ◽

Raoult's Law

AbstractThe humidity surrounding a sample is an important variable in scientific experiments. Biological samples in particular require not just a humid atmosphere but often a relative humidity (RH) that is in equilibrium with a stabilizing solution required to maintain the sample in the same state during measurements. The controlled dehydration of macromolecular crystals can lead to significant increases in crystal order, which often leads to higher diffraction quality. Devices that can accurately control the humidity surrounding crystals on a beamline have led to this technique being increasingly adopted, as experiments become easier and more reproducible. Matching the relative humidity to the mother liquor is the first step to allow the stable mounting of a crystal. In previous work, we measured the equilibrium relative humidity for a range of concentrations of the most commonly used precipitants and showed how this related to Raoult’s law for the equilibrium vapour pressure of water above a solution. However, a discrepancy between measured values and those predicted by theory could not be explained. Here, we have used a more precise humidity control device to determine equilibrium relative humidity points. The new results are in agreement with Raoult’s law. We also present a simple argument in statistical mechanics demonstrating that the saturated vapour pressure of a solvent is proportional to its mole fraction in an ideal solution: Raoult’s Law. The same argument can be extended to the case where solvent and solute molecules are of different size, as is the case with polymers. The results provide a framework for the correct maintenance of the RH surrounding samples.SynopsisThe equilibrium relative humidity values for a number of the most commonly used precipitants in biological macromolecule crystallisation have been measured using a new humidity control device. A simple argument in statistical mechanics demonstrates that the saturated vapour pressure of a solvent is proportional to its mole fraction in an ideal solution (Raoult’s Law). The same argument can be extended to the case where solvent and solute molecules are of different size.

Download Full-text

The reflection of vapour molecules at a liquid surface

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1931.0072 ◽

1931 ◽

Vol 131 (818) ◽

pp. 554-564 ◽

Cited By ~ 32

Keyword(s):

Kinetic Theory ◽

Vapour Pressure ◽

Liquid Surface ◽

Unit Area ◽

Kinetic Theory Of Gases ◽

Perfect Gas ◽

Saturated Vapour Pressure ◽

Saturated Vapour ◽

First Approximation ◽

Rate Of Evaporation

The rate of evaporation of a liquid may be calculated from the kinetic theory of gases if it be assumed that all vapour molecules which strike the surface enter the liquid and that, as a first approximation, the vapour behaves as a perfect gas. Under these circumstances, it follows from the kinetic theory of gases that m = mass of molecules leaving unit area per minute = mass of molecules striking unit area per minute from the saturated vapour = 14·63 P s /√T s gram/sq. cm. /min., where P s is the saturated vapour pressure in millimetres of mercury at the surface temperature T s ° A.

Download Full-text