Compositions, articles, devices, and methods relating to droplets containing shielding fluids

Abstract

Described herein are compositions and articles relating to droplets comprising a carrier fluid and a shielding fluid, and related methods and devices for depositing droplets onto a surface. According to some embodiments, a composition is described, the composition comprising a carrier fluid, a shielding fluid, and one or more species for delivery to a surface of a base, the shielding fluid configured to at least partially surround the carrier fluid while the composition is applied to the surface of the base.

Description

[Technical field]

[0001] Related Applications This application claims the benefit of priority under U.S. Provisional Application No. 63 / 273,500, filed October 29, 2021, and U.S. Provisional Application No. 63 / 277,958, filed November 10, 2021, the disclosures of which are incorporated herein by reference in their entireties.

[0002] Technical Field Described herein are compositions and articles relating to droplets that include a carrier fluid and a shielding fluid, as well as related methods and devices for depositing the droplets onto a surface. [Background technology]

[0003] background Pesticide contamination causes over 20,000 deaths worldwide annually and is associated with up to 385 million acute illnesses, including cancer, neurological conditions, and birth defects. Pesticides contaminate every part of the environment, especially water and soil. For example, pesticides have been detected in 90% of agricultural water samples, 50% of shallow wells, and 33% of major deep aquifers across the United States. Recent studies have shown that 31% of agricultural soils worldwide are at high risk of pesticide contamination. These excess pesticides not only affect soil chemistry, but also cause the death of non-target organisms and damage the soil microbiome, which plays a role in replenishing plant nutrients in the soil. In addition to having significant human and environmental costs, pesticides also impose a large economic burden on farmers, who spend over $60 billion annually on pesticides worldwide, with pesticides contributing approximately 30% of production costs in certain crops (such as cotton).Therefore, there is an urgent need to reduce waste and overuse of pesticides. Summary of the Invention [Means for solving the problem]

[0004] overview Described herein are compositions and articles relating to droplets comprising a carrier fluid and a cloaking fluid, as well as related methods and devices for depositing droplets onto a surface. The subject matter of the invention in some cases involves interrelated products, alternative solutions to a particular problem, and / or multiple different uses of one or more systems and / or articles.

[0005] According to some embodiments, a composition is described, the composition comprising a carrier fluid, a shielding fluid, and one or more species for delivery to a surface of a base, the shielding fluid configured to at least partially surround the carrier fluid while the composition is applied to the surface of the base.

[0006] In certain embodiments, a composition includes a carrier fluid, a shielding fluid surrounding the carrier fluid, and one or more seeds for delivery to a surface of a base, the composition having a spreading factor equal to or greater than 0, the spreading factor being: S = σ 水+種、空気 -(σ 水+種、遮蔽流体 +σ 遮蔽流体、空気 ) where σ is the interfacial tension.

[0007] In some embodiments, a composition comprises a carrier fluid, a shielding fluid at least partially surrounding the carrier fluid, and one or more seeds for delivery to a surface of a base, the composition comprising an amount of the shielding fluid equal to or less than 5 volume percent relative to the total volume of the composition.

[0008] According to certain embodiments, a composition comprises a carrier fluid, a plurality of shielding fluids at least partially surrounding the carrier fluid, and one or more seeds for delivery to a surface of a base, the composition comprising the plurality of shielding fluids in an amount equal to or less than 5 volume percent relative to the total volume of the composition.

[0009] In some embodiments, an article is described that includes a base including a surface and a droplet deposited on the surface, the droplet including a carrier fluid, a shielding fluid at least partially surrounding the carrier fluid, and one or more seeds for delivery to the surface of the base.

[0010] In one particular embodiment, a method of depositing a droplet on a surface of a base is described, the method comprising the steps of: exposing a carrier fluid to a shielding fluid; at least partially surrounding the carrier fluid with the shielding fluid, thereby forming the droplet, the droplet comprising an amount of the shielding fluid equal to or less than 5 volume percent relative to a total volume of the droplet, the droplet comprising one or more species for delivery to the surface of the base; and depositing the droplet on the surface of the base.

[0011] According to some embodiments, a device is described, the device comprising a first compartment containing a carrier fluid, a second compartment containing a shielding fluid, and one or more seeds for delivery to a surface of a base, the device being configured to expose the carrier fluid to the shielding fluid such that the shielding fluid at least partially surrounds the carrier fluid, thereby providing the composition comprising an amount of the shielding fluid equal to or less than 5 volume % relative to a total volume of the composition.

[0012] Other advantages and novel features of the present invention will become apparent from the following detailed description of various non-limiting embodiments of the present invention, when considered in conjunction with the accompanying drawings. In the event that the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control. In the event that two or more documents incorporated by reference include conflicting and / or inconsistent disclosure with respect to each other, the document having the later effective date shall control.

[0013] Non-limiting embodiments of the present invention are described by way of example with reference to the accompanying drawings, which are schematic and are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown is typically labeled with a single number. For purposes of clarity, not every component is labeled in every drawing, nor every component of each embodiment of the present invention is shown unless illustration is necessary, so that a person skilled in the art can understand the present invention. [Brief description of the drawings]

[0014] [Figure 1A] FIG. 1A shows a schematic cross-sectional view of a droplet comprising a carrier fluid and a shielding fluid at least partially surrounding the carrier fluid, where the carrier fluid comprises a species, according to certain embodiments.

[0015] [Figure 1B] FIG. 1B shows a schematic cross-sectional view of a droplet comprising a carrier fluid and a shielding fluid at least partially surrounding the carrier fluid, where the shielding fluid comprises a species, according to certain embodiments.

[0016] [Figure 1C] FIG. 1C shows a schematic cross-sectional view of a droplet comprising a carrier fluid and a shielding fluid at least partially surrounding the carrier fluid, where the carrier fluid and the shielding fluid comprise a species, according to certain embodiments.

[0017] [Figure 1D]FIG. 1D shows a schematic cross-sectional view of a droplet including a carrier fluid and a shielding fluid partially surrounding the carrier fluid, according to certain embodiments.

[0018] [Diagram 2] FIG. 2 illustrates a schematic cross-sectional view of a droplet including a carrier fluid and a plurality of shielding fluids at least partially surrounding the carrier fluid, according to certain embodiments.

[0019] [Figure 3A] FIG. 3A shows a schematic cross-sectional view of a droplet comprising a carrier fluid and a shielding fluid at least partially surrounding the carrier fluid, where the droplet is deposited on a surface of a base, the carrier fluid comprises a species, and the shielding fluid is in contact with the surface, according to a particular embodiment.

[0020] [Figure 3B] FIG. 3B shows a schematic cross-sectional view of a droplet comprising a carrier fluid and a shielding fluid partially surrounding the carrier fluid, where the droplet is deposited on a surface of a base, the carrier fluid comprises a seed, and the carrier fluid is in contact with the surface, according to a particular embodiment.

[0021] [Figure 3C] FIG. 3C shows a schematic cross-sectional view of a droplet comprising a carrier fluid and a shielding fluid partially surrounding the carrier fluid, according to a particular embodiment, where the droplet is deposited on a surface of a base, the carrier fluid comprises a species, and both the carrier fluid and the shielding fluid are in contact with the surface.

[0022] [Figure 4A] 4A-4D illustrate a method of depositing a droplet onto a surface of a base according to certain embodiments. [Figure 4B] 4A-4D illustrate a method of depositing a droplet onto a surface of a base according to certain embodiments. [Figure 4C] 4A-4D illustrate a method of depositing a droplet onto a surface of a base according to certain embodiments. [Figure 4D] 4A-4D illustrate a method of depositing a droplet onto a surface of a base according to certain embodiments.

[0023] [Figure 5A] FIG. 5A shows a device including a nozzle for delivering droplets including a carrier fluid and a shielding fluid at least partially surrounding the carrier fluid, where the carrier fluid includes a species, according to certain embodiments.

[0024] [Figure 5B] FIG. 5B illustrates a device including two nozzles configured to generate droplets including a carrier fluid and a shielding fluid at least partially surrounding the carrier fluid, where the carrier fluid includes a species, according to a particular embodiment.

[0025] [Figure 6A] FIG. 6A shows a schematic of water sprayed onto a leaf (left) and a time-lapse image of water sprayed onto a cabbage leaf for 3 seconds (right) according to certain embodiments.

[0026] [Figure 6B] FIG. 6B shows a schematic diagram of an oil-shielded water droplet sprayed onto a leaf (left) and a time-lapse image of a water droplet shielded with about 1% by volume soybean oil sprayed onto a cabbage leaf for 1 second (right), according to certain embodiments.

[0027] [Figure 7] FIG. 7 shows droplet coverage expressed as a percentage of total leaf area and normalized by spray time according to certain embodiments.

[0028] [Figure 8A] FIG. 8A shows a schematic diagram of the experimental setup used to investigate water droplet collisions (left) according to one particular embodiment, as well as time-lapse images (right) of a water droplet collision viewed from the side (top) and from above (bottom).

[0029] [Figure 8B] FIG. 8B shows a schematic diagram of the experimental setup used to investigate the collision of oil-shielded water droplets (left) and time-lapse images (right) of the side (top) and top (bottom) views of the collision of a water droplet shielded with 1% by volume soybean oil, according to certain embodiments.

[0030] [Figure 9A] FIG. 9A shows a plot of normalized contact diameter as a function of time for seven different oil obstructions at an impact velocity of about 1.25 m / sec, according to certain embodiments.

[0031] [Figure 9B] FIG. 9B shows a plot of normalized maximum diameter as a function of correlation function f(Re,We) in accordance with certain embodiments.

[0032] [Figure 9C] FIG. 9C shows a plot of droplet center of gravity recoil height (hcm) normalized by droplet diameter (D) for different impact velocities, oils, and oil viscosities, according to certain embodiments.

[0033] [Figure 9D] FIG. 9D shows a plot of the recoil height (hcm) of the droplet center of gravity normalized by the droplet diameter (D) for different impact experiments plotted as a function of oil volume fraction in the shielding droplet, according to certain embodiments.

[0034] [Figure 10] FIG. 10 shows a plot of the average dynamic contact angle measured during the shrinkage stage of a water droplet occluded with 10 cSt silicone oil at low oil volume fraction (left), as well as snapshots taken during the shrinkage of oil-occluded droplets at 0.10 vol.% (top right) and 0.03 vol.% (bottom right) oil, according to certain embodiments.

[0035] [Figure 11]FIG. 11 shows a snapshot of the highest point of the droplet's center of gravity during contraction or recoil for selected experiments, according to certain embodiments.

[0036] [Figure 12A] FIG. 12A shows a schematic diagram depicting a water droplet bouncing off a superhydrophobic surface, according to one particular embodiment, where the upward arrow indicates motion away from the surface, and the droplet has a kinetic energy that can be expressed in terms of the coefficient of restitution (e), the recoil velocity (v), and the mass of the droplet (m).

[0037] [Figure 12B] FIG. 12B shows a schematic diagram depicting an oil-shielded water droplet adhering to a surface, where kinetic energy is removed from the droplet by the work of adhesion (Es) and viscous dissipation (EμI+EμII+EμIII), in accordance with certain embodiments.

[0038] [Figure 12C] FIG. 12C shows a plot of the ratio of the recoil kinetic energy of a pure water droplet to the sum of the work of adhesion and viscous dissipation as a function of droplet velocity, according to certain embodiments.

[0039] [Figure 13A] FIG. 13A shows the advancing and receding contact angles of water alone or oil alone on a superhydrophobic surface, according to certain embodiments.

[0040] [Figure 13B] FIG. 13B shows the advancing and receding contact angles of a water droplet occluded with 1% oil by volume, according to certain embodiments.

[0041] [Figure 14A] FIG. 14A shows an image of the results of spraying a superhydrophobic wafer with pure water for 3 seconds, according to a specific embodiment.

[0042] [Figure 14B]FIG. 14B shows an image of the results of spraying a superhydrophobic wafer with water masked with 1% by volume soybean oil, according to certain embodiments.

[0043] [Figure 14C] FIG. 14C shows a plot of retained mass of a droplet on a superhydrophobic surface for different spray times and different oil obscurations, according to certain embodiments.

[0044] [Figure 14D] FIG. 14D shows snapshots of coverage achieved by spraying soybean oil occluded droplets for 1 second on (a) cabbage, (b) kale, (c) lettuce, and (d) spinach leaves according to certain embodiments.

[0045] [Figure 14E] FIG. 14E shows a plot of droplet mass retained on leaves normalized by leaf area and spray time compared across four crop leaves for pure water and soybean oil-shielded water droplets shielded with 1% soybean oil by volume, according to certain embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] Detailed Description A major cause of pesticide waste and resulting overuse is poor spray or droplet retention on hydrophobic plant surfaces. Wax-like coatings on plant surfaces (e.g., leaves) result in hydrophobic surface properties that are a fundamental obstacle to pesticide retention because pesticide sprays consist of pesticide molecules dissolved or suspended in water droplets. As a result, the water droplets bounce off and / or roll off the plant surface, with the majority of what is sprayed being directed into the water and soil in the environment.

[0047] In agricultural sprays, droplet sizes range from 50 to 600 μm and droplet impact velocities range from 1 to 8 m / s, which corresponds to a Weber number range of 1 to 600. During impact, such droplets undergo expansion caused by inertial forces and contraction caused by surface tension. Whether the droplets adhere or bounce off is dictated by surface properties such as surface energy and leaf microtexture, and droplet properties such as surface tension, viscosity, density and impact velocity. Traditional methods for increasing droplet retention on plant surfaces include the use of (i) adjuvants to adjust droplet properties such as surface tension, viscosity or density; (ii) additives that can locally disrupt the wax-like coating on the leaf surface to promote adhesion; (iii) chemicals that create microscopic anchoring sites to which droplets adhere; or (iv) physical charged interactions that promote droplet adhesion.

[0048] Surfactants are the most widely used adjuvants aimed at improving spray coverage and retention. Although their effectiveness in improving droplet spreading on plant surfaces under static conditions is well documented, their ability to inhibit the recoil of impacting droplets is more complicated. Only specialized surfactants can diffuse to the droplet interface quickly enough to reduce the dynamic surface tension of the droplet during impact and stop the recoil. Furthermore, lack of universality is an issue since surfactants must be chemically stable against the diverse pesticide chemistries. Because surfactants reduce surface tension, they also make the sprayed droplets smaller, which exacerbates pesticide drift and environmental contamination. Finally, some commercially used surfactants may be more environmentally and biologically toxic than the active ingredient in the pesticide. For example, by adding fatty amine ethoxylate surfactants to Roundup®, these formulations cause more mitochondrial damage and necrosis in human cells, and such surfactants are much more toxic to amphibian populations than the active ingredient glyphosate alone.

[0049] Viscosity-modifying adjuvants, which utilize viscous dissipation during impact to prevent droplets from bouncing off the plant surface, offer limited improvement in spray retention efficiency on plant surfaces. High molecular weight polymer-based adjuvants that can significantly improve droplet spreading rheology have also been shown to slightly improve spray retention (e.g., about 2% improvement on leaf surfaces). In addition to the modest improvement, the need for careful control of pH for such formulations poses a major obstacle to robust implementation. Furthermore, electrostatic sprayers, which physically charge the spray droplets and introduce an attractive force toward grounded plant surfaces, suffer from high cost, which limits their applicability.

[0050] Unlike the above approaches, which are unsustainable, toxic, non-universal or expensive, vegetable-based oils are very promising as adjuvants that can promote droplet retention. Oils have been used in agriculture for centuries because of their insecticidal and fungistatic properties. Vegetable oils are generally recognized as safe, are understood to have no risk to the environment, and are widely used in food and agriculture. These oils have a much lower environmental footprint than synthetic pesticides because they are easily degradable by microorganisms in soil. Their impact on crop health is well understood, and they are not phytotoxic if used correctly. Some oils are more robust to resistance development in pests, and some vegetable oils have minimal impact on non-target insects such as honeybees. As a spray adjuvant, the lower the surface energy of the oil, the easier it will adhere to hydrophobic leaves compared to water. Oils are primarily formulated as oil-in-water emulsions, which require the use of surfactants with the above-mentioned disadvantages, and require complex mixing methods when used. Compared to oil-in-water emulsions, water-in-oil emulsions (greater than 10% oil by volume) have the potential for phytotoxicity, and therefore the large oil content limits the applicability of such formulations.

[0051] The inventors have found and recognized that compositions comprising droplets of a carrier fluid surrounded by a trace amount (e.g., equal to or less than 5% by volume) of a shielding fluid can be used to improve droplet retention on a base surface (e.g., an agricultural surface such as a leaf). In some embodiments, the carrier fluid may comprise water and the shielding fluid may comprise an oil, such as an edible and environmentally safe vegetable-based oil. By taking advantage of oil-water wetting kinetics and surface tension, the oil may be introduced after the formation of the water droplets, thereby avoiding the complexities of emulsification or the use of environmentally harmful surfactants.

[0052] The cloaked droplets described herein provide a simple, environmentally sustainable, inexpensive, and effective approach to improve the retention of sprays (e.g., pesticide sprays) on hydrophobic surfaces. The inventors have demonstrated that the methodology described herein provides robust recoil suppression on hydrophobic surfaces with a variety of different cloaking fluids spanning a wide range of viscosities and surface tensions over agriculturally relevant impingement conditions. The amount of cloaking fluid to achieve recoil suppression can be advantageously low (e.g., as little as 0.1% by volume), thereby avoiding potential phytotoxicity. Devices (e.g., sprayer devices) are also described herein that can be used to spray cloaked droplets onto hydrophobic base surfaces, providing improved droplet retention and resulting in significant reduction in waste. As described herein, improved droplet retention is achieved using edible and environmentally safe carrier and cloaking fluids (e.g., water and oil, respectively), thereby demonstrating great promise in reducing the human health and ecological impacts of pesticides.

[0053] According to some embodiments, compositions are described herein. The compositions may, in certain embodiments, include a carrier fluid. As used herein, the term "carrier fluid" generally refers to a fluid capable of transporting one or more species. In certain embodiments, for example and as described in more detail below, the carrier fluid may include a species for delivery to a surface of a base. FIG. 1A shows a schematic cross-sectional view of a droplet according to certain embodiments. Referring to FIG. 1A, a composition 102a (e.g., a droplet) includes a carrier fluid 104, and the carrier fluid 104 includes a species 108.

[0054] Any of a variety of suitable carrier fluids may be utilized. In some embodiments, for example, the carrier fluid comprises water, an aqueous solution, an oil, and / or a non-Newtonian fluid. Other carrier fluids are also possible. In some embodiments, a mixture of carrier fluids may be utilized (e.g., a mixture of water and a non-Newtonian fluid).

[0055] The composition may comprise carrier fluid in any of various suitable amounts.According to some embodiments, the composition comprises a relatively large amount of carrier fluid.In some embodiments, for example, the composition comprises carrier fluid in an amount of 95% or more by volume, 96% or more by volume, 97% or more by volume, 98% or more by volume, 99% or more by volume, 99.1% or more by volume, 99.2% or more by volume, 99.3% or more by volume, 99.4% or more by volume, 99.5% or more by volume, 99.6% or more by volume, 99.7% or more by volume, or 99.8% or more by volume, based on the total volume of the composition. In some embodiments, the composition comprises an amount of carrier fluid that is less than or equal to 99.9% by volume, less than or equal to 99.8% by volume, less than or equal to 99.7% by volume, less than or equal to 99.6% by volume, less than or equal to 99.5% by volume, less than or equal to 99.4% by volume, less than or equal to 99.3% by volume, less than or equal to 99.2% by volume, less than or equal to 99.1% by volume, less than or equal to 99% by volume, less than or equal to 98% by volume, less than or equal to 97% by volume, or less than or equal to 96% by volume, based on the total volume of the composition. Combinations of the ranges recited above are possible (e.g., the composition comprises an amount of carrier fluid equal to or greater than 95% and equal to or less than 99.9% by volume, based on the total volume of the composition; the composition comprises an amount of carrier fluid equal to or greater than 99% and equal to or less than 99.5% by volume, based on the total volume of the composition). Other ranges are also possible. In some embodiments, the amount of carrier fluid can be determined by imaging the droplets using a microscope lens, microspectroscopy, or nuclear magnetic resonance (NMR).In certain embodiments, the amount of carrier fluid may be determined by analyzing the input flow rate of the carrier fluid used to produce the composition.

[0056] According to some embodiments, the composition includes a shielding fluid. As used herein, the term "shielding fluid" generally refers to a first fluid configured to at least partially surround a second fluid, such that a layer of the first fluid spreads to at least partially surround the second fluid. In certain embodiments, for example, the shielding fluid is configured to at least partially surround the carrier fluid. In some embodiments, the shielding fluid at least partially surrounds the carrier fluid (e.g., while the composition is being applied to a surface, as described in more detail herein). For example, referring to FIG. 1A, the composition 102a includes a shielding fluid 106 that at least partially surrounds the carrier fluid 104.

[0057] In certain embodiments, the presence of a shielding fluid (e.g., at least partially surrounding the carrier fluid) may advantageously enhance retention of the composition when disposed (e.g., sprayed) onto a surface of a base. In some embodiments, for example, the shielding fluid may be configured to secure the composition to the surface of the base during contraction of the composition, e.g., when the composition is disposed (e.g., sprayed) onto the surface of the base.

[0058] Any of a variety of suitable shielding fluids may be utilized. In some embodiments, for example, the shielding fluid comprises an oil, a surfactant, an aqueous solution, and / or a non-Newtonian fluid. In some embodiments in which the shielding fluid comprises an oil, the oil may be a vegetable-based oil and / or a petroleum-based oil. Although virtually any oil may be utilized, non-limiting examples of suitable oils include soybean oil, canola oil, silicone oil, mineral oil, linseed oil, cottonseed oil, anise oil, bergamot oil, castor oil, cedarwood oil, citronella oil, eucalyptus oil, jojoba oil, lavandin oil, lemongrass oil, methyl salicylate oil, mint oil, mustard oil, and / or orange oil. Other shielding fluids are also possible. According to some embodiments, mixtures of shielding fluids may be utilized (e.g., mixtures of oil and non-Newtonian fluids, mixtures of oils, etc.).

[0059] The shielding fluid may have any of a variety of suitable viscosities, in some embodiments, for example, the shielding fluid has a viscosity equal to or greater than 1 cSt, equal to or greater than 25 cSt, equal to or greater than 50 cSt, equal to or greater than 75 cSt, equal to or greater than 100 cSt, equal to or greater than 150 cSt, equal to or greater than 200 cSt, equal to or greater than 250 cSt, equal to or greater than 300 cSt, equal to or greater than 350 cSt, equal to or greater than 400 cSt, or equal to or greater than 450 cSt. In certain embodiments, the shielding fluid has a viscosity equal to or less than 500 cSt, equal to or less than 450 cSt, equal to or less than 400 cSt, equal to or less than 350 cSt, equal to or less than 300 cSt, equal to or less than 250 cSt, equal to or less than 200 cSt, equal to or less than 150 cSt, equal to or less than 100 cSt, equal to or less than 75 cSt, equal to or less than 50 cSt, or equal to or less than 25 cSt. Combinations of the ranges listed above are possible (e.g., the shielding fluid has a viscosity equal to or greater than 1 cSt and equal to or less than 500 cSt, the shielding fluid has a viscosity equal to or greater than 50 cSt and equal to or less than 75 cSt). Other ranges are also possible.

[0060] The shielding fluid may have any of a variety of suitable surface tensions, in some embodiments, for example, the shielding fluid has a surface tension equal to or greater than 1 mN / m, equal to or greater than 5 mN / m, equal to or greater than 10 mN / m, equal to or greater than 15 mN / m, equal to or greater than 20 mN / m, equal to or greater than 25 mN / m, equal to or greater than 30 mN / m, equal to or greater than 35 mN / m, equal to or greater than 40 mN / m, or equal to or greater than 45 mN / m. In certain embodiments, the shielding fluid has a surface tension of less than or equal to 50 mN / m, less than or equal to 45 mN / m, less than or equal to 40 mN / m, less than or equal to 35 mN / m, less than or equal to 30 mN / m, less than or equal to 25 mN / m, less than or equal to 20 mN / m, less than or equal to 15 mN / m, less than or equal to 10 mN / m, or less than or equal to 5 mN / m. Combinations of the ranges listed above are possible (e.g., the shielding fluid has a surface tension of less than or equal to 1 mN / m and less than or equal to 50 mN / m, the shielding fluid has a surface tension of less than or equal to 20 mN / m and less than or equal to 25 mN / m). Other ranges are also possible.

[0061] The composition may include any suitable amount of shielding fluid. In certain embodiments, the composition includes a substantially low amount of shielding fluid. According to certain embodiments, it may be advantageous to employ a low amount of shielding fluid to avoid the possibility of a phytotoxic composition. In some embodiments, for example, the composition comprises an amount of shielding fluid equal to or less than 5 vol.%, equal to or less than 4 vol.%, equal to or less than 3 vol.%, equal to or less than 2 vol.%, equal to or less than 1 vol.%, equal to or less than 0.9 vol.%, equal to or less than 0.8 vol.%, equal to or less than 0.7 vol.%, equal to or less than 0.6 vol.%, equal to or less than 0.5 vol.%, equal to or less than 0.4 vol.%, equal to or less than 0.3 vol.%, equal to or less than 0.2 vol.%, equal to or less than 0.1 vol.%, equal to or less than 0.05 vol.%, or equal to or less than 0.04 vol.%, based on the total volume of the composition. In certain embodiments, the composition comprises an amount of shielding fluid equal to or greater than 0.02 vol.%, equal to or greater than 0.04 vol.%, equal to or greater than 0.05 vol.%, equal to or greater than 0.1 vol.%, equal to or greater than 0.2 vol.%, equal to or greater than 0.3 vol.%, equal to or greater than 0.4 vol.%, equal to or greater than 0.5 vol.%, equal to or greater than 0.6 vol.%, equal to or greater than 0.7 vol.%, equal to or greater than 0.8 vol.%, equal to or greater than 0.9 vol.%, equal to or greater than 1 vol.%, equal to or greater than 2 vol.%, equal to or greater than 3 vol.%, or equal to or greater than 4 vol.%, based on the total volume of the composition.Combinations of the ranges recited above are possible (e.g., the composition includes an amount of shielding fluid greater than or equal to 0.02% and less than or equal to 5% by volume relative to the total volume of the composition, the composition includes an amount of shielding fluid greater than or equal to 0.5% and less than or equal to 1% by volume relative to the total volume of the composition). Other ranges are also possible. In some embodiments, the amount of shielding fluid can be determined by imaging the droplets using a microscope lens, microspectroscopy, or nuclear magnetic resonance (NMR). In certain embodiments, the amount of shielding fluid can be determined by analyzing the input flow rate of the shielding fluid used to generate the composition.

[0062] The composition (e.g., droplets) may have any of a variety of suitable shapes. In some embodiments, for example and as shown in FIG. 1A, the composition 102a (e.g., droplets) may be substantially spherical. In other embodiments, the composition may be non-spherical, as the disclosure is not intended to be limiting in this respect. The composition may have any of a variety of suitable sizes. In certain embodiments, for example and as shown in FIG. 1A, the composition 102a (e.g., droplets) may have a maximum characteristic dimension (e.g., maximum diameter) 114. According to some embodiments, the composition may have a maximum characteristic dimension equal to or greater than 100 micrometers, equal to or greater than 200 micrometers, equal to or greater than 300 micrometers, equal to or greater than 400 micrometers, equal to or greater than 500 micrometers, equal to or greater than 1 mm, equal to or greater than 2 mm, equal to or greater than 3 mm, or equal to or greater than 4 mm. In certain embodiments, the composition may have a maximum characteristic dimension of less than or equal to 5 mm, less than or equal to 4 mm, less than or equal to 3 mm, less than or equal to 2 mm, less than or equal to 1 mm, less than or equal to 500 micrometers, less than or equal to 400 micrometers, less than or equal to 300 micrometers, or less than or equal to 200 micrometers. Combinations of the ranges listed above are possible (e.g., the composition has a maximum characteristic dimension of less than or equal to 5 mm and greater than or equal to 100 micrometers, the composition has a maximum characteristic dimension of less than or equal to 500 micrometers and less than or equal to 1 mm). Other ranges are also possible. In certain embodiments, the maximum characteristic dimension of the composition may be determined by scanning electron microscopy (SEM) and / or transmission electron microscopy (TEM).

[0063] According to certain embodiments, the composition includes one or more species for delivery to the surface of the base. For example, referring to FIG. 1A, the composition 102a includes a carrier fluid 104, a shielding fluid 106 at least partially surrounding the carrier fluid 104, and a species 108. In some embodiments, the species may be at least partially dissolved and / or suspended in the carrier fluid, as shown in FIG. 1A. In other embodiments, the species may be at least partially dissolved and / or suspended in the shielding fluid. For example, FIG. 1B shows a schematic cross-sectional view of a composition 102b (e.g., a droplet) including a carrier fluid 104 and a shielding fluid 106 at least partially surrounding the carrier fluid 104, where the shielding fluid 106 includes a species 108 dissolved and / or suspended in the shielding fluid 106, according to certain embodiments. In still other embodiments, the species may be at least partially dissolved and / or suspended in both the carrier fluid and the shielding fluid. For example, FIG. 1C shows a schematic cross-sectional view of a composition 102c (e.g., a droplet) comprising a carrier fluid 104 and a shielding fluid 106 at least partially surrounding the carrier fluid 104, where both the carrier fluid 104 and the shielding fluid 106 comprise species 108, which may be dissolved and / or suspended in the carrier fluid 104 and the shielding fluid 106, according to certain embodiments.

[0064] According to certain embodiments, the composition may include more than one species (e.g., two species, three species, four species, five species, etc.). In some embodiments, for example, the composition may include more than one species dissolved and / or suspended in the carrier fluid and / or the shielding fluid. In certain embodiments, the composition may include at least one species dissolved and / or suspended in the carrier fluid and at least one species dissolved and / or suspended in the shielding fluid. In other embodiments, the composition may include at least a first species and a second species dissolved and / or suspended in the carrier fluid. In yet other embodiments, the composition may include at least a first species and a second species dissolved and / or suspended in the shielding fluid.

[0065] Any of a variety of suitable seeds may be utilized. In some embodiments, the seeds are agricultural chemicals. In certain embodiments, the seeds are pesticides, fertilizers, pesticide compounds, and / or surfactants. Non-limiting examples of seeds include insecticides, herbicides, fungicides, weed killers, and / or foliar fertilizers. Other seeds are also possible.

[0066] According to some embodiments, the composition comprises: S = σ 水+溶質、空気 -(σ 水+溶質、遮蔽流体 +σ 遮蔽流体、空気 ) where σ is the interfacial tension.

[0067] In some embodiments, the composition may be configured to have a diffusion coefficient equal to or greater than 0. In some such embodiments, the shielding fluid may completely surround the carrier fluid (i.e., the shielding fluid covers 100% of the surface area of ​​the carrier fluid). For example, with reference to Figures 1A-1C, the shielding fluid 106 completely surrounds the carrier fluid 104.

[0068] In certain embodiments, the composition may be configured to have a diffusion coefficient less than 0. In some such embodiments, the shielding fluid may partially surround the carrier fluid. FIG. 1D shows a schematic cross-sectional view of a composition 102d (e.g., a droplet) including a carrier fluid 104 and a shielding fluid 106 partially surrounding the carrier fluid 104, according to certain embodiments. In some embodiments, for example, the surface 105a of the carrier fluid 104 may be an interface between the carrier fluid 104 and an external medium (e.g., air, a surface, etc.), while the surface 105b of the carrier fluid 104 is an interface between the carrier fluid 104 and the shielding fluid 106. Although FIG. 1D shows the species 108 dissolved and / or suspended in the carrier fluid 104, the shielding fluid 106 may include the species 108 in addition to or instead of the carrier fluid 104 including the species 108, as described above.

[0069] The shielding fluid may encompass any of a variety of suitable surface areas of the carrier fluid. In certain embodiments, for example, the shielding fluid encompasses 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, or 99% or more of the surface area of ​​the carrier fluid. In some embodiments, the shielding fluid encompasses 100% or less, 99% or less, 95% or less, 90% or less, 80% or less, 70% or less, or 60% or less of the surface area of ​​the carrier fluid. Combinations of the ranges listed above are possible (e.g., the shielding fluid surrounds equal to or greater than 50% and equal to or less than 100% of the surface area of ​​the carrier fluid, the shielding fluid surrounds equal to or greater than 70% and equal to or less than 80% of the surface area of ​​the carrier fluid). Other ranges are also possible. The surface area of ​​the carrier fluid surrounded by the shielding fluid can be determined using methods such as SEM and / or TEM.

[0070] According to some embodiments, the composition may include a plurality of shielding fluids at least partially surrounding the carrier fluid. FIG. 2 shows a schematic cross-sectional view of a composition 102e (e.g., a droplet) that, in some embodiments, includes a carrier fluid 104 and a plurality of shielding fluids 106 (e.g., a first shielding fluid 106a and a second shielding fluid 106b) at least partially surrounding the carrier fluid 104. Although FIG. 2 shows a first shielding fluid and a second shielding fluid, additional shielding fluids are also possible (e.g., a third shielding fluid, a fourth shielding fluid, a fifth shielding fluid, etc.), as the disclosure is not intended to be limiting in this respect. In some embodiments, the first shielding fluid 106a may at least partially surround the carrier fluid 104, and the second shielding fluid 106b may at least partially surround the first shielding fluid 106a.

[0071] Although FIG. 2 shows the species 108 dissolved and / or suspended in the carrier fluid 104, the first shielding fluid 106a and / or the second shielding fluid 106b may contain the species 108 in addition to or instead of the carrier fluid 104 containing the species 108, as the disclosure is not intended to be limiting in this respect.

[0072] According to certain embodiments and as shown in FIG. 2, the first shielding fluid 106a may completely surround the carrier fluid 104, and the second shielding fluid 106b may completely surround the first shielding fluid 106a. In some embodiments, not shown in the figures, the first shielding fluid may partially surround the carrier fluid such that the surface of the carrier fluid is an interface between the carrier fluid and the second shielding fluid. In other embodiments, the second shielding fluid may partially surround the first shielding fluid such that the surface of the first shielding fluid is an interface between the first shielding fluid and an external medium (e.g., air, a surface, etc.). In still other embodiments, both the first shielding fluid and the second shielding fluid partially surround the carrier fluid such that the surface of the carrier fluid is an interface between the carrier fluid and an external medium (e.g., air, a surface, etc.).

[0073] In certain embodiments, articles are described. For example, FIG. 3A shows a schematic cross-sectional view of an article 103a including a droplet including a carrier fluid 104 and a shielding fluid 106 at least partially surrounding the carrier fluid 104, according to certain embodiments, where the droplet is deposited on a surface 112 of a base 110, and the shielding fluid 106 is in contact with the surface 112. FIG. 3A shows a non-limiting embodiment of the shielding fluid in contact with the surface of the base after deposition of the composition. According to some embodiments, the carrier fluid may be in contact with the surface of the base instead of or in addition to the shielding fluid contacting the surface of the base, depending on the components of the composition, the properties of the composition, the composition of the base, and / or the rate at which the composition is deposited. For example, Figure 3B shows a schematic cross-sectional view of an article 103b including a droplet comprising carrier fluid 104 and shielding fluid 106 partially surrounding carrier fluid 104, where the droplet is deposited on surface 112 of base 110 and carrier fluid 104 is in contact with surface 112. Figure 3C shows a schematic cross-sectional view of an article 103c including a droplet comprising carrier fluid 104 and shielding fluid 106 partially surrounding carrier fluid 104, where the droplet is deposited on surface 112 and both carrier fluid 104 and shielding fluid 106 are in contact with surface 112, where the droplet is deposited on surface 112 and both carrier fluid 104 and shielding fluid 106 are in contact with surface 112, according to certain embodiments.

[0074] Although Figures 3A-3C show that the carrier fluid 104 contains species 108, the shielding fluid 106 may contain species 108 in addition to or instead of the carrier fluid 104 containing species 108, as the disclosure is not intended to be limiting in this respect, as described above.

[0075] According to some embodiments, a method of depositing droplets onto a surface of a base is described. Figures 4A-4D show a method of depositing droplets onto a surface of a base according to certain embodiments. As shown in Figure 4A, the method may in some embodiments include exposing a carrier fluid 104 (e.g., including species 108) to a shielding fluid 106. Although Figure 4A shows that the carrier fluid 104 includes species 108, as the disclosure is not intended to be limiting in this respect, in some embodiments, the shielding fluid 106 may include species 108 in addition to or instead of the carrier fluid 104 including species 108, as described above.

[0076] 4B, as a result of exposing the carrier fluid 104 to the shielding fluid 106, the shielding fluid 106 may, in some embodiments, at least partially surround the carrier fluid 104, thereby forming a droplet 208. In certain embodiments, as shown in FIGS. 4C-4D, the method further includes depositing the droplet 208 on the surface 112 of the base 110. In some embodiments, the droplet may be formed in situ such that the shielding fluid at least partially surrounds the carrier fluid while the droplet is being deposited on the surface of the base. Although FIG. 4D shows the shielding fluid 106 in contact with the surface 112 of the base 110, the embodiment shown in FIG. 3B in which the carrier fluid 104 is in contact with the surface 112, or the embodiment shown in FIG. 3C in which both the carrier fluid 104 and the shielding fluid 106 are in contact with the surface 112 are also possible, as the disclosure is not intended to be limiting in this respect.

[0077] Any of a variety of suitable bases may be employed. In certain embodiments, the base is an agricultural base. Examples of agricultural bases include, but are not limited to, plants or parts of plants. In certain embodiments, for example, the base may be a leaf (e.g., a tree leaf, a cabbage leaf, a kale leaf, a lettuce leaf, a spinach leaf, etc.), a stem, a fruit, a vegetable, a flower, a root, a seed, a nut, and / or the like. Other bases are also possible. The surface of the base may be at least partially hydrophobic (e.g., having a water contact angle of more than 90 degrees) or superhydrophobic (e.g., having a water contact angle of more than 150 degrees) in certain embodiments.

[0078] In certain embodiments, a device is described. FIG. 5A shows a device 301a including a nozzle 206 for delivering droplets 208 including a carrier fluid and a shielding fluid at least partially surrounding the carrier fluid, where the carrier fluid includes a species, according to certain embodiments. The device 301a may include a first compartment 202 containing a carrier fluid 104 and a second compartment 204 containing a shielding fluid 106, in some embodiments. In certain embodiments, the device includes a species that may be at least partially dissolved and / or suspended in the carrier fluid and / or the shielding fluid, as described above. Although FIG. 5A shows that the carrier fluid 104 includes the species 108, the shielding fluid 106 may include the species 108 in addition to or instead of the carrier fluid 104 including the species 108, as described above, since the disclosure is not intended to be limiting in this respect.

[0079] In certain embodiments, although not shown in the figures, the species may be separate from the carrier fluid and the shielding fluid, such that the species may be placed in a third compartment separate from the first and second compartments. In some such embodiments, the device may be configured to expose the species to the carrier fluid and / or the shielding fluid via a nozzle, conduit, and / or channel that fluidly connects the first compartment and / or the second compartment to the third compartment.

[0080] In some embodiments in which the composition includes more than one shielding fluid (eg, a first shielding fluid and a second shielding fluid), the device may include an additional compartment for containing the additional shielding fluid.

[0081] According to some embodiments, the device is configured to expose the carrier fluid to the shielding fluid such that the shielding fluid at least partially surrounds the carrier fluid. For example, in certain embodiments, the device includes at least one nozzle. For example, with reference to FIG. 5A, the device 301a includes a nozzle 206, which in some embodiments may be configured to simultaneously spray the carrier fluid 104 and the shielding fluid 106 such that droplets 208 are formed (e.g., in situ as the droplets are applied to the surface). In certain embodiments, the device 301a may be configured to deposit the droplets 208 on a surface of the base.

[0082] In other embodiments, the device may include two nozzles. Figure 5B shows a device 301b including a first nozzle 206a and a second nozzle 206b according to a particular embodiment. According to a particular embodiment, the two nozzles may be configured to expose the carrier fluid 104 to the shielding fluid 106 such that the shielding fluid 106 at least partially surrounds the carrier fluid 104, thereby generating droplets 208 including the carrier fluid and the shielding fluid at least partially surrounding the carrier fluid, where the carrier fluid includes a species. In some such embodiments, the first nozzle 206a is fluidly connected to a first compartment 202 containing the carrier fluid 104 (e.g., including the species 108), and the second nozzle 206b is fluidly connected to a second compartment 204 containing the shielding fluid 106. 5B shows that the carrier fluid 104 includes the species 108, however, the shielding fluid 106 may include the species 108 in addition to or instead of the carrier fluid 104 including the species 108, as the disclosure is not intended to be limiting in this respect. In certain embodiments, the device 301b may be configured to deposit droplets 208 onto a surface of the base.

[0083] According to certain embodiments, not shown in the figures, one or more compartments and / or one or more nozzles of the device may be coupled to a pressure source, which in certain embodiments may pressurize fluid within the one or more compartments and / or one or more nozzles such that the fluid (e.g., carrier fluid, shielding fluid) may be dispensed (e.g., sprayed) from the device (e.g., through a nozzle).

[0084] According to certain embodiments, one or more nozzles of the device can be configured to spray the composition and / or its components (e.g., carrier fluid, shielding fluid) at any of a variety of suitable velocities. In some embodiments, for example, one or more nozzles of the device are configured to spray the composition and / or its components at a velocity equal to or greater than 1 m / s, equal to or greater than 2 m / s, equal to or greater than 3 m / s, equal to or greater than 4 m / s, equal to or greater than 5 m / s, equal to or greater than 6 m / s, equal to or greater than 7 m / s, equal to or greater than 8 m / s, equal to or greater than 9 m / s, equal to or greater than 10 m / s, or equal to or greater than 15 m / s. In certain embodiments, one or more nozzles of the device are configured to spray the composition and / or its components at a velocity of less than or equal to 20 m / s, less than or equal to 15 m / s, less than or equal to 10 m / s, less than or equal to 9 m / s, less than or equal to 8 m / s, less than or equal to 7 m / s, less than or equal to 6 m / s, less than or equal to 5 m / s, less than or equal to 4 m / s, less than or equal to 3 m / s, or less than or equal to 2 m / s. Combinations of the ranges listed above are possible (e.g., one or more nozzles of the device are configured to spray the composition and / or its components at a velocity of less than or equal to 1 m / s and less than or equal to 20 m / s, and one or more nozzles of the device are configured to spray the composition and / or its components at a velocity of less than or equal to 5 m / s and less than or equal to 10 m / s). Other ranges are also possible.

[0085] The compositions, articles, methods, and / or devices described herein may be used in any of a variety of suitable applications. According to some embodiments, the compositions may include an advantageously low amount of a shielding fluid (e.g., oil) that improves the retention (e.g., spray retention) of the composition on a base surface, such as a surface of a plant part, compared to conventional compositions that include, for example, water only, oil-in-water (O / W) emulsions, and / or water-in-oil (W / O) emulsions. In certain embodiments, for example and as described herein, the compositions may include one or more species (e.g., pesticides) and may be configured to improve the retention of one or more species on a base surface (e.g., a plant part).

[0086] The following examples are intended to illustrate certain embodiments of the present invention, but do not exemplify the full scope of the invention. EXAMPLES

[0087] Example 1 The following example illustrates the use of minute amounts of a shielding fluid to improve spray retention of droplets on a base surface.

[0088] Compound droplet impact has been of increasing interest over the last few years. However, water-in-oil compound droplet impact has not been investigated on superhydrophobic surfaces and at low concentrations of oil (e.g., 1% by volume or less). As described in more detail below, compound droplets that adhere to hydrophobic plant surfaces were created by shielding water droplets with vegetable oil.

[0089] Figure 6A shows time-lapse images of water droplets sprayed onto a cabbage leaf for 3 seconds using an agricultural sprayer. In this case, the nozzle produced droplets with volume median diameters of 341–403 μm at velocities of 5–10 m / s. Although some droplets do land on the leaf where defects exist, the majority of the sprayed water bounces off, highlighting the problem of poor droplet retention in traditional pesticide sprays. In contrast, Figure 6B demonstrates the effectiveness of shielding the water droplets with approximately 1% soybean oil, a ubiquitous plant-based oil that (i) is used in food; (ii) is approved for use in agriculture by the U.S. Environmental Protection Agency (EPA); (iii) has minimal environmental impact; and (iv) is inexpensive. More uniform coverage was achieved with one-third the spray time. The ability of this approach to reduce pesticide waste was quantified by normalizing the spray time by the percentage of the leaf area covered by droplets. As shown in FIG. 7, oil shielding was found to result in a 5.25-fold reduction in pesticide waste, indicating that this simple, inexpensive, and environmentally sustainable approach is very promising.

[0090] To fully understand the potential of this technique to improve droplet retention, it is systematically investigated using two types of nanoengineered superhydrophobic surfaces. Droplet impact dynamics are tested at various agriculturally relevant spray rates and Weber numbers, and the effect of occlusion by different oils of various surface tensions and viscosities is systematically investigated. The effect of oil fraction is explored, and a simple energy state framework is presented to explain the recoil suppression observed for oil-occluded droplets. A practical embodiment of the system is tested, and a significant improvement in spray retention on nanoengineered superhydrophobic surfaces and vegetable crop leaves is demonstrated.

[0091] Single water droplets of different diameters were formed by forcing the liquids through needles of different gauges. A secondary needle was used to apply oil shielding, as shown in Figure 8B. The flow rates of all fluids were controlled using a syringe pump. For oil fractions below 1 vol.%, the stainless steel needle was hydrophobized to prevent any wicking losses. The impact velocity was varied by controlling the release height of the dispensed droplets. A silicon nanograss surface was used as a superhydrophobic surface model. The surface had an average texture size and spacing of about 200 nm and was functionalized with different hydrophobicity modifiers. The advancing and receding contact angles of DI water on this base were 163.9° and 159.3°, respectively, on the octadecyltrichlorosilane (OTS)-coated surface and 166.6° and 164.8°, respectively, on the trichloro(1h,1h,2h,2h-perfluorooctyl)silane (FS)-coated surface. The impact experiment was observed using a Photron Fastcam SA1.1 high-speed camera.

[0092] Figure 8A shows time-lapse images of a water droplet (diameter approx. 3 mm and impact velocity approx. 1.25 m / s) impacting on an OTS-nanograss surface, viewed from the side (top) and from above (bottom). The droplet behaved as expected, undergoing a symmetric shrinkage phase before completely recoiling from the surface. Figure 8B shows the impact under identical conditions (velocity and diameter) with a droplet occluded with 1% by volume soybean oil. The expansion phase was nearly identical in terms of maximum diameter and expansion time, whereas the shrinkage phase in the occluded case was significantly different. During shrinkage, the contact line of the droplet was pinned to the surface by the oil. This significantly reduced the shrinkage rate and caused the droplet to adhere to the surface. This configuration resulted in a maximum height of the droplet's center of gravity (h cm ) to provide a quantitative measurement for tracking recoil suppression. cm is labeled in Figure 8B. To confirm that the diffusion phase of the collision is not perturbed, and to more thoroughly explore the dynamics of recoil suppression, droplet collision experiments were performed with nine different oils of various viscosities and surface tensions.

[0093] FIG. 9A shows the time evolution of droplet contact diameter (D(t)) normalized by the droplet's initial diameter D0 for six representative oil occlusion conditions. All of these experiments were performed on OTS-coated nanoglass surfaces with 1 vol.% oil fraction and impact velocity of about 1.25 m / s. Only the control DI water droplet lost contact with the surface after recoil under these conditions, while all oil occlusions were successful in suppressing recoil. The expansion phase for all droplets was roughly identical in terms of maximum droplet diameter and expansion time, further supporting the observations in FIG. 8A-8B. During the contraction phase, the contact line of the occluded droplet began to pin to the surface. FIG. 9B shows the normalized maximum diameter for impact experiments with different oil occlusions, droplet sizes, and impact velocities. Across agriculturally relevant conditions, the droplet Weber number varied from 45 to 639, and the Reynolds number varied from 1972 to 7875. In this regime, the normalized maximum diameter at the full expansion scale is given by Eq.

number

[0094] To focus on the contraction stage and rebound behavior of the shielded droplet, the maximum height of the droplet's center of gravity (h cm ) was reconsidered. Using high-speed video of droplet collisions, cmwas measured and normalized by the initial droplet diameter D0. Figure 9C plots the normalized recoil height for various impact velocities, oil occlusion conditions, and surfaces. In these experiments, the oil fraction of the occluded droplet was kept constant at 1 vol%. The plot demonstrates the robustness of this approach in promoting droplet retention. Regardless of the oil type, oil viscosity, or oil surface tension, occlusion resulted in droplet attachment on the superhydrophobic surface for velocities between 0.8 and 2.3 m / s, which correspond to agriculturally relevant We numbers of 81 to 646. The oil viscosity was varied between 1.3 cst and 68 cst. The oil surface tension was varied between 16 mN / m and 32 mN / m.

[0095] The higher the surface tension and viscosity, the greater the h cm A general trend towards lower impact velocity was observed in these experiments. At the upper limit of impact velocity, splashing of both DI water and oil-shielded droplets was observed. Interestingly, the satellite droplets in the control case scattered from the surface, whereas the satellite droplets in the oil-shielded case almost entirely adhered to the surface. Typically, smaller droplet sizes that are more prone to drift are chosen to enhance coverage on plant surfaces, but these results indicate that this methodology may enable the use of larger droplets that are resistant to drifting while still benefiting from the enhanced coverage provided by satellite droplets.

[0096] Figure 9D demonstrates the effect of oil fractions of two representative oils, low and high viscosity. Both oils were effective in preventing retention at 0.1% by volume, promoting the practical robustness of this approach. This volume of oil is comparable to the total amount of adjuvant used in traditional agricultural sprays, including those where oil-in-water emulsions are employed.

[0097] Figure 10 shows some of the complications that arise at lower oil fractions. When the volume fraction reaches 0.1%, the oil rim pinning the droplet is found to be discontinuous. This rim subsequently disappears as the oil fraction decreases below 0.1%. At these volume fractions, the average contact angle during the shrinkage phase also changed dramatically, from about 30° to about 140°. At a volume fraction of 0.01%, the shrinkage phase was comparable to that of a DI water droplet, indicating that a minimal amount of oil is required for this approach to be effective. Figure 11 shows some examples of maximum normalized recoil heights for different impact conditions, highlighting the distinction between the bounce, adhesion, and splash-off regimes.

[0098] Oil shielding was demonstrated to provide a simple yet robust approach to enhance droplet retention on superhydrophobic surfaces over a range of agriculturally relevant impact conditions for a wide range of oils, oil viscosities, and oil volume fractions. However, it is also clear from these impacts that the mechanisms governing the shrinkage dynamics are extremely complex. There are several macroscopic and microscopic pinning events that result in energy losses during shrinkage. High-speed video showed that the formation of an oil rim plays a role in pinning the droplet to the surface. However, it is also clear that the rim thickness, continuity, and symmetry are highly variable. Additional complexities arise when the oil volume fraction drops below 0.1%. In this case, oil scarcity at the interface needs to be considered in any model that seeks to accurately capture the dynamics of these compound droplet impacts. Although further examination of the ongoing fluid and interface interactions is required to explain the explicit dynamics of this system, a simple analysis of the energy state can be used to explain droplet retention.

[0099] An impacting droplet can be considered in two states: (i) at its maximum diameter during impact and (ii) after the droplet has rebounded. Focusing first on the latter state, when a water droplet rebounds from a superhydrophobic surface, its kinetic energy can be expressed as the product of its incident kinetic energy and the coefficient of restitution (e0), as shown in FIG. 12A. For a water droplet, the coefficient of restitution on a superhydrophobic surface is a function of the Weber number. Using this trend, for any water droplet of a given size and incident velocity, one skilled in the art can estimate the rebound kinetic energy that the droplet will possess. Any technique to suppress this rebound requires that this energy be removed from the droplet. Returning to the other state of interest, when the droplet reaches its maximum diameter, two types of energy dissipation mechanisms can be considered, one due to surface tension and the other due to viscosity.

[0100] The work of adhesion (E s ) is the surface tension of the fluid in contact with the surface (σ outer ), the receding contact angle of the droplet (θ r ), and the maximum radius of the droplet on the surface (R max ) can be described.

number

[0101] In the shielded case, it was assumed that the entire contact area with the surface is covered by oil during the impact event. This is a reasonable assumption considering that oil preferentially wets surfaces compared to water. The second dissipation mechanism is only present in the oil shielded case and is due to the viscosity of the oil shield itself. Viscous dissipation E μ is the dissipation of the oil cap (E μI ), dissipation in the oil film below the droplet (E μII ) and dissipation at the oil protuberance (E μIII )

number

[0102] Comparing the relative magnitudes of these terms, viscous dissipation in the oil protrusion at the contact line of the receding drop appeared to be the dominant term. It is noted that dissipation in the water drop does not need to be considered in this energy balance since it is already accounted for in the restitution coefficient. Using this framework, if the sum of the work of adhesion and viscous dissipation balances the recoil kinetic energy, the drop will adhere, and if the recoil kinetic energy is much greater than the sum of these terms, the drop should bounce off.

[0103] Figure 12C plots the recoil kinetic energy normalized by the sum of the work of adhesion and viscous dissipation for each of the experimental conditions for which the model is applicable. For each droplet, the recoil kinetic energy possessed by a water droplet of similar size and incident velocity was estimated using the restitution coefficient. The work of adhesion and viscous dissipation were estimated using the maximum contact diameter observed during each droplet impact. The contact angle used in this case is the quasi-static receding angle of the compound droplet on the superhydrophobic surface, as reported in Figures 13A-13B. Taking these explanations into account, the sum of the work of adhesion and viscous dissipation seemed to balance well against the recoil kinetic energy for all oil-occluded droplets, indicating why they could stick. In contrast, pure water droplets (which were the only experiments in which droplets recoiled) have a kinetic energy about three times larger than the sum of the dissipation terms.

[0104] Considering that the energy dissipation model can accurately capture the recoil behavior of the droplet, the effect of higher viscosity and occlusion time scales is worth mentioning. The impact of a droplet occluded in 500 cSt silicone oil with 1% oil volume fraction was observed by high-speed video. This high viscosity oil resulted in a slight shrinkage phase compared to the pure water case, but this was much less effective in suppressing recoil than in the other occluded droplets with oil viscosities below 70 cSt. Thus, this experiment with high viscosity oil provided some insight into the occlusion time scale and its importance in suppressing recoil. Indeed, the simple energy state model presented above would have predicted that the droplet would adhere if all other assumptions were maintained. However, the occlusion time scales of oils of different viscosities relative to the water droplet suggest that the assumption that the oil covers the entire interfacial area does not hold in this case of occluding with highly viscous oil. Specifically, all of the other oils used in the study have viscosities below 70 cSt, suggesting that they should be able to occlude the water droplet as well as the interface between the droplet and the superhydrophobic surface (SHS) due to their low viscosity in about 0.5 ms. In contrast, a high viscosity oil would take about 50 ms to coat the entire droplet and on the order of tens of milliseconds to occlude the interfacial area between the droplet and the SHS. Considering that the entire contraction phase occurs in about 10-20 ms, this may not be enough time for a highly viscous oil to suppress recoil.

[0105] A wide range of fluid and interface parameters at single droplet impact were explored, and a practical device that could be used to demonstrate practical improvements in spray retention was implemented. A prototype was developed that included two nozzles, one for water and one for oil.

[0106] To test the ability of the sprayer device to improve retention in the most extreme cases, both water droplets and soybean oil-shielded water droplets were sprayed onto a large OTS nanograss surface. The retained mass of the droplets was weighed in both cases to measure the retention performance in terms of mass. Figure 14A shows a photograph of the results of spraying water droplets onto the surface for 3 seconds. As expected, almost all water droplets sprayed onto the superhydrophobic surface bounce off. Figure 14B shows a photograph of the results of spraying water droplets shielded with about 1 wt% soybean oil for 3 seconds. Almost immediately after the start of spraying, the water droplets start to adhere to the surface, and by the end of the 3 seconds, a 96-fold improvement in retained mass was measured for the soybean oil case (Figure 14C). Figure 14C also shows retention data for experiments in which oil-shielded droplets were sprayed for only 1 second and 2 seconds. This trend was found to be consistent for other vegetable oils commonly used in agriculture, such as canola oil or cottonseed oil, demonstrating the robustness of this approach. These experiments demonstrate the potential of this technology to significantly reduce the amount of pesticide sprayed; even with one-third the spray time, the technology allows for a 7.3- to 14-fold improvement in mass retention, depending on the oil used. Very importantly, these improvements are achieved with oils that are inexpensive, widely used, and safe for the environment, farm workers, and crops. These oils are also widely compatible with pesticidal chemicals and are known to retard evaporation of pesticide spray droplets and enhance foliar absorption of pesticides.

[0107] In Figures 6A-7, the ability of the prototype device sprayer to reduce spray waste in terms of leaf surface coverage was demonstrated. To demonstrate the ability of the sprayer device to improve retained mass, three additional crop leaves (kale, spinach and lettuce) were sprayed and the results of a 1 second spray on all leaves are shown in Figure 14D. The total retained mass of droplets was normalized by leaf area and spray time for both water droplets and soybean oil-shielded droplets and is shown in Figure 14E. A greater than three-fold improvement in normalized retained mass across the leaf was observed, demonstrating the broad practical applicability of this approach in improving droplet retention.

[0108] In conclusion, a simple, environmentally sustainable, inexpensive, and effective approach to improve spray retention on hydrophobic and superhydrophobic surfaces was demonstrated. By shielding droplets with trace amounts of oil (less than 1% by volume), robust recoil suppression was demonstrated on two superhydrophobic surfaces with nine different oils spanning a wide range of viscosities and surface tensions, across agriculturally relevant impact conditions. Recoil suppression with as little as 0.1% by volume of oil per droplet was also demonstrated. A physical understanding of recoil suppression was provided by modeling the viscous and surface energy-based dissipation during the impact of these shielded droplets. Finally, these findings were translated into a prototype sprayer device, which was able to demonstrate up to 102-fold improvement in retention on superhydrophobic surfaces and up to 5.25-fold reduction in wastage when sprayed on crop leaves. These improvements were achieved using food and environmentally safe vegetable oils, demonstrating that the presented methodology holds great promise in reducing the human health and ecological impacts of pesticides.

[0109] Estimation of impact velocity, centre of gravity and coefficient of restitution: Impact velocity and centre of gravity (COM) data were extracted from the high-speed video by image analysis of each frame. Care was taken when illuminating the background and surface so that the edge of the droplet was the darkest feature in the video. This allowed the use of a simple thresholding method to form a mask of the droplet outline. For each row of pixels in the droplet mask, the width of the mask was taken to be the local diameter of the droplet, assuming that the droplet maintained axial symmetry at all times. The partial mass of each row was calculated as the mass of a one-pixel thick disk. The mass average of these partial masses, weighed at each of its vertical positions, gave the COM. The impact velocity was calculated by differentiating the vertical COM for each frame with respect to time and taking into account the velocity just before impact. As the droplet recoil velocity is highly variable throughout the recoil process, an alternative definition of the coefficient of restitution was established,

number

[0110] Construction of a working embodiment: To test the coverage of leaf surfaces with agriculturally relevant sprays, a container of deionized water was pressurized at 2 atmospheres (30 psi) and flowed through a TG-1 TeeJet Full Cone Spray Tip (Spray Smarter), and the resulting spray was directed at the leaves. A distance of approximately 75 cm was maintained between the sprayer and the leaves. An AA250AUH Automatic Spray Nozzle (Spraying Systems) was installed just upstream of the spray tip and spray time was controlled by switching it on and off. The water droplets from the primary nozzle were occluded with oil using a secondary airbrush sprayer. Care was taken to ensure that the overlap angle of the two nozzles ensured that the oil from the secondary sprayer did not directly contaminate the surface. The flow rates of both fluids were controlled to ensure 1% occlusion by weight.

[0111] Hydrophobization of Needles: Stainless steel needles were hydrophobized by immersing them in a solution of 5 mM solvated fluoroalkyl (C10) phosphonic acid (SP-06-003, obtained from Specific Polymers) in methanol for 24 hours. A flat stainless steel control surface subjected to the same conditions had a water-air contact angle of greater than 90°, confirming successful hydrophobization.

[0112] Contact angle measurements: Contact angles were measured using a Rame-Hart contact angle goniometer.

[0113] Confirmation of low volume fraction of oil: All volume fractions of oil were confirmed by measuring the weight of the dispensed liquid over time.

[0114] Although several embodiments of the invention have been described and illustrated herein, various other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein will be readily envisioned by those skilled in the art, and each such variation and / or modification is deemed to be within the scope of the invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and that the actual parameters, dimensions, materials, and / or configurations will depend on the particular application(s) for which the teachings of the invention are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Thus, it is to be understood that the above embodiments are presented by way of example only, and that within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described and claimed. The invention relates to each individual feature, system, article, material, kit, and / or method described herein. Furthermore, any combination of two or more such features, systems, articles, materials, kits, and / or methods is included within the scope of the present invention, unless such features, systems, articles, materials, kits, and / or methods are mutually inconsistent.

[0115] All definitions and those used herein should be understood to take precedence over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms. As used herein, the indefinite articles "a" and "an" should be understood to mean "at least one," unless the contrary is expressly stated in the specification and claims.

[0116] As used herein, the phrase "and / or" should be understood in the present specification and claims to mean "either or both" of the elements so conjoined, i.e., elements that are present conjunctively in some cases and disjunctively in other cases. Multiple elements listed with "and / or" should be interpreted in the same manner, i.e., "one or more" of the elements so conjoined. Other elements other than the elements specifically identified by the "and / or" clause may optionally be present, whether related or unrelated to the specifically identified elements. Thus, as a non-limiting example, a reference to "A and / or B," when used in conjunction with open-ended language such as "comprising," may refer in one embodiment to only A (optionally including elements other than B), in another embodiment to only B (optionally including elements other than A), and in yet another embodiment to both A and B (optionally including other elements), etc.

[0117] As used herein, in the specification and claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" shall be interpreted as being inclusive, i.e., including at least one of a number or recited elements, but also including more than one, and including additional unrecited items as necessary. Only terms expressly stated to the contrary, such as "only one of" or "exactly one of," or, when used in the claims, "consisting of," shall refer to the inclusion of exactly one of a number or recited elements. In general, the term "or," when used herein, shall only be interpreted as indicating exclusive alternatives (i.e., "one or the other, but not both") when preceded by terms of exclusivity, such as "either," "one of," "only one of," or "exactly one of." "Consisting essentially of," when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0118] As used herein, in the specification and claims, the phrase "at least one" in connection with one or more listed elements should be understood to mean at least one element selected from any one or more of the elements in the list, but not necessarily including at least one of each and every element specifically listed within the list of elements, nor excluding any combination of elements among the list of elements. This definition also allows that elements other than the elements specifically identified within the list of elements to which the phrase "at least one" refers may optionally be present, whether related or unrelated to the specifically identified elements. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently, "at least one of A and / or B") can refer, in one embodiment, to at least one (optionally including more than one) A (and optionally including elements other than B) in the absence of B; in another embodiment, to at least one (optionally including more than one) B (and optionally including elements other than A) in the absence of A; in yet another embodiment, to at least one (optionally including more than one) A and at least one (optionally including more than one) B (and optionally including other elements), etc.

[0119] Also, unless expressly stated to the contrary, it should be understood that in any method claimed herein that includes more than one step or act, the order of the method steps or acts is not necessarily limited to the order in which the method steps or acts are recited.

[0120] In the claims and the above specification, all transitional phrases such as "comprising," "including," "holding," "having," "containing," "involving," "possessing," "consisting of," and the like, are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed or semi-closed transitional phrases, respectively, as defined in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

1. a carrier fluid; a shielding fluid; one or more seeds for delivery to the surface of the base; wherein the shielding fluid is configured to at least partially surround the carrier fluid while the composition is applied to the surface of the base.

2. a carrier fluid; a shielding fluid surrounding the carrier fluid; one or more seeds for delivery to the surface of the base; wherein the composition has a spreading factor greater than or equal to 0, and the spreading factor is S = s 水＋種、空気 -(s 水＋種、遮蔽流体 +s 遮蔽流体、空気 ) where σ is the interfacial tension.

3. a carrier fluid; a shielding fluid at least partially surrounding the carrier fluid; one or more seeds for delivery to the surface of the base; 1. A composition comprising:

4. a base including a surface; and droplets deposited on the surface, the droplets comprising a carrier fluid, a shielding fluid at least partially surrounding the carrier fluid, and one or more species for delivery to the surface of the base.

5. 1. A method of depositing droplets onto a surface of a base, the method comprising: exposing the carrier fluid to a shielding fluid; at least partially surrounding the carrier fluid with the shielding fluid, thereby forming the droplet, the droplet comprising the shielding fluid in an amount equal to or less than 5% by volume relative to a total volume of the droplet, the droplet comprising one or more species for delivery to the surface of the base; depositing the droplet on the surface of the base; A method comprising:

6. a first compartment containing a carrier fluid; a second compartment containing a shielding fluid; one or more seeds for delivery to the surface of the base; 1. A device comprising: a carrier fluid; and a shielding fluid comprising: a carrier fluid; a shielding fluid at least partially surrounding the carrier fluid; the carrier fluid being configured to expose the carrier fluid to the shielding fluid, thereby providing the composition comprising an amount of the shielding fluid equal to or less than 5% by volume relative to the total volume of the composition.

7. The composition, article, method, or device of any of claims 1 to 6, wherein the carrier fluid comprises water, an aqueous solution, an oil, and / or a non-Newtonian fluid.

8. The composition, article, method, or device of any of claims 1 to 6, wherein the shielding fluid comprises an oil, a surfactant, an aqueous solution, and / or a non-Newtonian fluid.

9. 9. The composition, article, method or device of claim 8, wherein the oil is a vegetable-based oil and / or a petroleum-based oil.

10. 9. The composition, article, method, or device of claim 8, wherein the oil is soybean oil, canola oil, silicone oil, mineral oil, linseed oil, cottonseed oil, anise oil, bergamot oil, castor oil, cedarwood oil, citronella oil, eucalyptus oil, jojoba oil, lavandin oil, lemongrass oil, methyl salicylate oil, mint oil, mustard oil, and / or orange oil.

11. 7. The composition, article, method, or device of any of claims 1 to 6, wherein the one or more species are at least partially dissolved and / or suspended in the carrier fluid.

12. The composition, article, method, or device of any of claims 1 to 6, wherein the one or more species are at least partially dissolved and / or suspended in the shielding fluid.

13. The composition, article, method, or device of any of claims 1 to 6, wherein the base is an agricultural base.

14. 14. The composition, article, method or device of claim 13, wherein the agricultural substrate is a plant or part of a plant.

15. The composition, article, method, or device of any of claims 1 to 6, wherein the surface is at least partially hydrophobic.

16. The device of claim 6 , wherein the device includes at least one nozzle.

17. 17. The device of claim 16, wherein the at least one nozzle is configured to spray the composition.

18. The device of claim 16 , wherein the at least one nozzle is configured to expose the carrier fluid to the shielding fluid.

19. The composition has a spreading factor greater than or equal to 0, the spreading factor being: S = s 水＋種、空気 -(s 水＋種、遮蔽流体 +s 遮蔽流体、空気 ) 4. The composition of claim 1, wherein σ is the interfacial tension.

20. 3. The composition of claim 1, wherein the composition comprises the shielding fluid in an amount less than or equal to 5% by volume relative to the total volume of the composition.

21. 4. The composition of claim 1, wherein the composition comprises the shielding fluid in an amount equal to or less than 1% by volume relative to the total volume of the composition.

22. a carrier fluid; a plurality of shielding fluids at least partially surrounding the carrier fluid; one or more seeds for delivery to the surface of the base; wherein the composition comprises the plurality of shielding fluids in an amount less than or equal to 5 volume percent relative to the total volume of the composition.

23. The composition of claim 22 , wherein the plurality of shielding fluids comprises a first shielding fluid and a second shielding fluid.

24. 24. The composition of claim 23, wherein the first shielding fluid at least partially surrounds the carrier fluid and the second shielding fluid at least partially surrounds the first shielding fluid.

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