Contact Angle Hysteresis. IV. Contact Angle Measurements on Heterogeneous Surfaces<sup>1</sup>

Dettre, Robert H.; Johnson, R. E.

doi:10.1021/j100889a012

Cited by 278 publications

(152 citation statements)

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“…Figure 2a. Results show that the advancing contact angle is considerably higher than the receding contact angle in the same pore throat, consistent with previous studies [18,22,[43][44][45]. The difference between ACA and RCA is attributed to the blemishes on non-ideal surfaces which results in pinning the interfaces to the solid surface [46].…”

Section: Contact Angle Measurementsupporting

confidence: 89%

Direct Measurement of Static and Dynamic Contact Angles Using a Random Micromodel Considering Geological CO2 Sequestration

Jafari

Jung

2017

Sustainability

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Abstract:The pore-level two-phase fluids flow mechanism needs to be understood for geological CO 2 sequestration as a solution to mitigate anthropogenic emission of carbon dioxide. Capillary pressure at the interface of water-CO 2 influences CO 2 injectability, capacity, and safety of the storage system. Wettability usually measured by contact angle is always a major uncertainty source among important parameters affecting capillary pressure. The contact angle is mostly determined on a flat surface as a representative of the rock surface. However, a simple and precise method for determining in situ contact angle at pore-scale is needed to simulate fluids flow in porous media. Recent progresses in X-ray tomography technique has provided a robust way to measure in situ contact angle of rocks. However, slow imaging and complicated image processing make it impossible to measure dynamic contact angle. In the present paper, a series of static and dynamic contact angles as well as contact angles on flat surface were measured inside a micromodel with random pattern of channels under high pressure condition. Our results showed a wide range of pore-scale contact angles, implying complexity of the pore-scale contact angle even in a highly smooth and chemically homogenous glass micromodel. Receding contact angle (RCA) showed more reproducibility compared to advancing contact angle (ACA) and static contact angle (SCA) for repeating tests and during both drainage and imbibition. With decreasing pore size, RCA was increased. The hysteresis of the dynamic contact angle (ACA-RCA) was higher at pressure of one megapascal in comparison with that at eight megapascals. The CO 2 bubble had higher mobility at higher depths due to lower hysteresis which is unfavorable. CO 2 bubbles resting on the flat surface of the micromodel channel showed a wide range of contact angles. They were much higher than reported contact angle values observed with sessile drop or captive bubble tests on a flat plate of glass in previous reports. This implies that more precaution is required when estimating capillary pressure and leakage risk.

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Section: Contact Angle Measurementsupporting

confidence: 89%

Direct Measurement of Static and Dynamic Contact Angles Using a Random Micromodel Considering Geological CO2 Sequestration

Jafari

Jung

2017

Sustainability

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“…Secondly, contact angle hysteresis can occur. This phenomenon has been long recognized and studied (Dettre & Johnson, 1964 ;Oliver et al, 1980). The general observation is (Adamson & Gast, 1997) that the contact angle measured for a liquid advancing across a surface exceeds that of one receding from the surface.…”

Section: Assumptions and Limitationsmentioning

confidence: 98%

Water rise kinetics in refilling xylem after desiccation in a resurrection plant

et al. 2000

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The acropetal water refilling kinetics of the dry xylem of branches (up to 80 cm tall) of the resurrection plant Myrothamnus flabellifolia were determined with high temporal resolution by observation of light refraction at the advancing water front and the associated recurving of the folded leaves. To study the effect of gravity on water rise, data were acquired for cut upright, horizontal and inverted branches. Water rise kinetics were also determined with hydrostatic and osmotic pressure as well as at elevated temperatures (up to 100mC) under laboratory conditions and compared with those obtained with intact (rooted) and cut branches under field conditions. Experiments in which water climbed under its capillary pressure alone, showed that the axial flow occurred only in a very few conducting elements at a much higher rate than in many of the other ones. The onset of transpiration of the unfolded and green leaves did not affect the rise kinetics in the ' prominent ' conducting elements. Application of pressure apparently increased the number of elements making a major contribution to axial xylem flow. Analysis of these data in terms of capillary-pressure-driven water ascent in leaky capillaries demonstrated that root pressure, not capillary pressure, is the dominant force for rehydration of rooted, dry plants. The main reasons for the failure of capillary forces in xylem refilling were the small, rate-limiting effective radii of the conducting elements for axial water ascent (c. 1 µm compared with radii of the vessels and tracheids of c. 18 µm and 3 µm, respectively) and the very poor wetting of the dry walls. The contact (wetting) angles were of the order of 80m and decreased on root or externally applied hydrostatic pressure. This supported our previous assumption that the inner walls of the dry conducting elements are covered with a lipid layer that is removed or disintegrates upon wetting. Consistent with this, potassium chloride and, particularly, sugars exerted an osmotic pressure effect on axial water climbing (reflection coefficients zero, but small). Although the osmotically active solutes apparently suppressed radial water spread through the tissue to the leaf cells, they reduced the axial water ascent rather than accelerating it as predicted by the theory of capillary-driven water rise in leaky capillaries. Killing cells by heat treatment and removal of the bark, phelloderm, cortex and phloem also resulted in a reduction of the axial rise rate and final height. These observations demonstrated that radial water movement driven by the developing osmotic and turgor pressure in the living cells was important for the removal of the lipid layer from the walls of those conducting elements that were primarily not involved in water rise. There is some evidence from field measurements of the axial temperature gradients along rooted branches that interfacial (Marangoni) streaming facilitated lipid removal (under formation of vesicle-like structures and lipid bodies) upon wetting.

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“…As the surface micromorphology does not change significantly, the wettability of the epicuticular waxes seems to be more or less constant, although the chemical composition of the cuticular wax changes considerably during leaf ageing (Marksta$ dter, 1994). In contrast to smooth surfaces, rough hydrophobic surfaces have considerably higher contact angles because air is enclosed between the surface structures, and the contact area between water and surface is drastically reduced (Dettre & Johnson, 1964 ;Holloway, 1970). In such cases, the contact angle mainly depends on the surface tension of the water and not on the adhesion between water and surface.…”

Section: Leaf Surfaces Micromorphology and Wettabilitymentioning

confidence: 99%

Seasonal changes of leaf surface contamination in beech, oak, and ginkgo in relation to leaf micromorphology and wettability

1998

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The leaf surfaces of beech, oak and ginkgo have been investigated with respect to contamination with particles during one growing season. Based on the observation that particles are removed from water-repellent leaves by rain (Lotus effect) the three species were selected because they differ in leaf surface micromorphology and wettability. Leaves of beech are smooth, lacked wax crystals and were pwettable. Those of ginkgo were rough because their cells were convex and were densely covered by wax crystals, resulting in permanent water repellency. Leaves of oak were covered by waxes and were water repellent when young, but, a few weeks after leaf expansion had ceased the waxes were rapidly eroded. These differences in wettability resulted in different amounts of contamination. Ginkgo collected a very small number of particles during the whole vegetation period. In beech the contamination was significantly higher, but fairly constant, whereas oak leaves accumulated particles with age.

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Contact Angle Hysteresis. IV. Contact Angle Measurements on Heterogeneous Surfaces¹

Cited by 278 publications

References 1 publication

Direct Measurement of Static and Dynamic Contact Angles Using a Random Micromodel Considering Geological CO2 Sequestration

Direct Measurement of Static and Dynamic Contact Angles Using a Random Micromodel Considering Geological CO2 Sequestration

Water rise kinetics in refilling xylem after desiccation in a resurrection plant

Seasonal changes of leaf surface contamination in beech, oak, and ginkgo in relation to leaf micromorphology and wettability

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Contact Angle Hysteresis. IV. Contact Angle Measurements on Heterogeneous Surfaces1

Cited by 278 publications

References 1 publication

Direct Measurement of Static and Dynamic Contact Angles Using a Random Micromodel Considering Geological CO2 Sequestration

Direct Measurement of Static and Dynamic Contact Angles Using a Random Micromodel Considering Geological CO2 Sequestration

Water rise kinetics in refilling xylem after desiccation in a resurrection plant

Seasonal changes of leaf surface contamination in beech, oak, and ginkgo in relation to leaf micromorphology and wettability

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Contact Angle Hysteresis. IV. Contact Angle Measurements on Heterogeneous Surfaces¹