scholarly journals Influence of Multiple Factors on the Wettability and Surface Free Energy of Leaf Surface

2019 ◽  
Vol 9 (3) ◽  
pp. 593 ◽  
Author(s):  
Yong He ◽  
Shupei Xiao ◽  
Jianjian Wu ◽  
Hui Fang
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Solid Surface ◽  
Leaf Surface ◽  
Plant Protection ◽  
Plant Protection Products ◽  
Surface Wettability ◽  
Multiple Factors ◽  
Key Factor

The wettability of plant leaves directly reflects leaf hydrophilicity, which is the key factor that influences the adhesion of liquid pesticide as well as affects plant protection products (PPP) efficacy. Generally, the wettability of leaf surface is quantified by the contact angle and surface free energy (SFE), which are mainly dependent on leaf surface properties, liquid properties and other spraying parameters. Therefore, the aim of this paper was to investigate the SFE of rice and rape leaves with the variation of leaf status, leaf surface, and probe liquid as well as the influence of droplet falling height, solid surface, and PPP concentration on the wettability. The results showed that: (1) the dispersive components of SFE of rice and rape account for a large proportion which are closely related to their hydrophobicity—the abaxial of rape new leaf and the adaxial of rape old leaf are easier to wet comparing with rice and rape leaves in other statuses; (2) the increase of droplet falling height had a significant effect on improving the wettability between wax surface and adjuvant solution, while it had little improving effect on the wettability between wax surface and water; (3) the wettability of different solid surface varied greatly, and the order of wettability from good to bad is water-sensitive paper (WSP), wax, rape leaf, and rice leaf; (4) the effect of PPP concentration on the leaf surface wettability is significant, the contact angle decreased with the increase of PPP concentration, and the wettability of microemulsion is better than that of suspending agent and wettable powder. In conclusion, the SFE and wettability of crop leaf surface determine the suitable type of PPP, studying the influence of multiple factors on leaf surface wettability can provide a reliable reference for providing scientific guidance as well as improving the effective utilization of PPP.

scholarly journals Some problems of characterization of a solid surface via the surface free energy changes

2017 ◽  
Vol 35 (7-8) ◽  
pp. 647-659 ◽  
Author(s):  
Emil Chibowski
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Experimental Determination ◽  
Surface Free Energy ◽  
Solid Surface ◽  
Contact Angles ◽  
Absolute Value ◽  
Receding Contact

During the processes occurring at a solid surface, the changes in the surface free energy take place. The knowledge about surface free energy is very helpful for understanding the processes taking place on the surface. However, experimental determination of solid surface free energy is still not a fully solved problem. In this paper, some problems dealing with calculation of solid surface free energy from contact angle are discussed based on literature values of advancing and receding contact angles measured on four different fluoropolymers surface. The four approaches most often used for the calculation are described and especial focus on the approach in which both the advancing and receding contact angles is paid. It is concluded that using probing liquids the absolute value of solid surface free energy cannot be determined. However, the determined apparent values of the energy are very helpful to understand the conditions necessary for a given process to occur.

Within-tree variations in the surface free energy of wood assessed by contact angle analysis

2011 ◽  
Vol 46 (1-3) ◽  
pp. 287-298 ◽  
Author(s):  
Davide Rossi ◽  
Sergio Rossi ◽  
Hubert Morin ◽  
Antonio Bettero
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Contact Angle Analysis

Hydrophobic and Oleophilic Filter Paper for Oil/Water Separation

2019 ◽  
Vol 798 ◽  
pp. 385-390
Author(s):  
Sunisa Jindasuwan ◽  
Sitthisuntorn Supothina
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Water Contact Angle ◽  
Filter Paper ◽  
Diesel Oil ◽  
Selective Removal ◽  
Water Contact ◽  
Water Separation ◽  
Filter Papers

The separation of oil from water is significance for environmental de-pollution application. To obtain selectivity of liquid, filter papers were coated to bear highly hydrophobic and oleophilic functionality that can allow only oils to pass through them. The coating solutions were prepared by mixing poly(methylhydro siloxane, PMHS) and fumed silica at various proportions. To determine an optimum coating condition, properties of the treated filter papers were investigated by measuring water contact angle and surface free energy, examining surface morphology and testing for selective removal of diesel oil from water. The optimum coating solution was at the PMHS:fumed silica weight ratio of 1.25:1.00. The treated filter paper exhibited high hydrophobicity with water contact angle of 142.80 ± 0.36 degrees and surface free energy of 0.78 mJ/m2. In addition, it exhibited high selective removal of diesel oil from water with oil absorption capacity of 2.3 g/g.

scholarly journals Variability of Leaf Wetting and Water Storage Capacity of Branches of 12 Deciduous Tree Species

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1158
Author(s):  
Klamerus-Iwan Anna ◽  
Łagan Sylwia ◽  
Zarek Marcin ◽  
Słowik-Opoka Ewa ◽  
Bartłomiej Wojtan
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Storage Capacity ◽  
Leaf Surface ◽  
Surface Condition ◽  
Water Storage ◽  
Deciduous Tree ◽  
Horse Chestnut ◽  
Water Storage Capacity ◽  
Canopy Water

Leaf surface wettability and factors which determine it are key in determining the water storage capacity of tree crowns and thus the interception of entire stands. Leaf wettability, expressed as the droplet inclination angle, and the surface free energy largely depend not only on the chemical composition of the leaves but also on their texture. The study concerns 12 species of trees common in Central Europe. The content of epicuticular waxes was determined in the leaves, and values ranging from 9.145 [µg/cm2] for horse chestnut (Aesculus hippocastanum L.) to 71.759 [µg/cm2] for birch (Betula pendula Roth.) were obtained. Each additional µg/cm2 increases the canopy water storage capacity by 0.067 g g−1. For all species, the inclination angles of water, diiodomethane and glycerin droplets to the leaf surface were measured and the surface free energy was calculated. It is shown that it is the wax content and the species that constitute independent predictors of water storage capacity. These factors explain the 95.56% effect on the value of canopy water storage capacity. The remaining 4.44% indicate non-species-related individual features or the ability to mitigate pollutants as well as possible environmental factors. Wax analyzed separately from other factors causes a slight increase (by 0.067 g/g) of S. Nevertheless, the influence of the surface condition as a result of species-related variability is decisive for the value of the canopy water storage capacity.

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