WO2018122872A1 - Patterned metallic nanobrushes for capture of atmospheric humidity - Google Patents

Patterned metallic nanobrushes for capture of atmospheric humidity Download PDF

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WO2018122872A1
WO2018122872A1 PCT/IN2017/050621 IN2017050621W WO2018122872A1 WO 2018122872 A1 WO2018122872 A1 WO 2018122872A1 IN 2017050621 W IN2017050621 W IN 2017050621W WO 2018122872 A1 WO2018122872 A1 WO 2018122872A1
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hydrophilic
ag
hydrophobic
surface
nanobrushes
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PCT/IN2017/050621
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French (fr)
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Thalappil Pradeep
Depanjan SARKAR
Anindita Mahapatra
Anirban SOM
Avijit BAIDYA
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INDIAN INSTITUTE OF TECHNOLOGY MADRAS (IIT Madras)
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D5/00Condensation of vapours; Recovering volatile solvents by condensation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00Nanotechnology for materials or surface science, e.g. nanocomposites
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00Manufacture or treatment of nanostructures

Abstract

The present invention relates to hydrophilic-hydrophobic patterned metallic grassland surfaces grown in air for capturing atmospheric humidity. The said surfaces were created from silver nanowires (AgNWs), synthesized under ambient conditions at room temperature using electrospray deposition-based technique. The hydrophilic-hydrophobic patterned Ag nanobrushes comprise of three distinct regions - (i) the Ag-core, (ii) hydrophobic coating with fluorothiol (FT) on the Ag-core and (iii) tiny hydrophilic regions (Ag nanoparticles, Ag NPs) on the hydrophobic background. Ag core gives the strength to the brushes, while the FT coating creates the hydrophobic background. Further, Ag deposition on this resulted in Ag NPs decoration all over the nanobrushes. These Ag NPs, embedded in the FT layer, act as hydrophilic zones, responsible for condensation of atmospheric humidity.

Description

DESCRIPTION

TITLE OF THE INVENTION

PATTERNED METALLIC NANOBRUSHES FOR CAPTURE OF ATMOSPHERIC HUMIDITY

FIELD OF THE INVENTION

The present invention generally relates to a method for capturing atmospheric water and more particularly to the synthesis of hydrophilic-hydrophobic nanostructured surface for efficient atmospheric water capture even at low relative humidity, prepared by ambient droplet sprays.

BACKGROUND OF THE INVENTION

Water scarcity is one of the biggest problems of the modem world. In regions affected by water scarcity, atmospheric water capture is considered as an important method for providing clean water. Significant quantum of research has gone into this area in the past few decades to make an efficient device to capture water at a high rate, in a cost effective way. Advancement in nanotechnology provides an opportunity to the researchers to mimic nature and make nanostructured surfaces for water capture. Stenocara beetles of Namib Desert are one such inspiration from nature due to their unique fog collection capability (Naidu, 2001 ; White et al, 2013). Electron microscopic images of these beetles shows a unique array of hydrophilic regions distributed on a superhydrophobic background (Hou et al, 2014), which facilitates efficient condensation of atmospheric water. Inspired by this, many biomimetic, patterned surfaces were made for fog collection (Edmonds and Vollrath, 1992; Thickett et al, 2011). Some other inspirations from nature are certain cactaceae species which live in arid environments and are extremely drought-tolerant (Ju et al., 2012). These species were shown to have a structure with spines and trichomes which enable them to collect water efficiently from the atmosphere. Grasslands are also examples of natural atmospheric water harvesters. Hence, micro/nano- structuring of the surface plays a critical role in determining the efficiency of water capture.

Metallic nanostructures are of great interest in recent research due to their unusual electrical and electromagnetic properties (Maier et al, 2003; Moskovits, 2005; Wang et al, 2007) which are totally different from their bulk properties (Roduner, 2006). Enhanced electric field around these structures make them potential substrates for surface-enhanced Raman spectroscopy (SERS) (Moskovits, 2005; Willets and Van Duyne, 2007; Stiles et al., 2008), sensing of various biological and non-biological compounds (Kolmakov and Moskovits, 2004; Anker et al, 2008; Zhang et al, 2008), catalyzing various reactions (Rolison, 2003; Tian et al., 2003; Bavykin et al., 2006; Polshettiwar et al., 2011; Sarkar et al, 2016), data storage (Pham et al, 2004; Liu et al, 2012), etc. Apart from these, metallic nanostructures can be used for their interesting mechanical properties (Pan et al, 2001 ; Wang and Song, 2006), porosity (Hristovski et al, 2008; Wang et al, 2010; Han et al., 2011), alignment (Wang et al., 2004), and many more. Even though such nanostructures have potential applications in different areas still it is very difficult to synthesize these structures in a controlled fashion, especially when it comes to well- defined structures. Several methods have been developed to create such nanostructures which include chemical (Choy, 2003; Khodakov et al, 2007; Hu et al., 2010; Kumar and Ando, 2010) and physical (Kong et al, 2001 ; Helmersson et al., 2006; Hawkeye and Brett, 2007) vapor deposition, spray pyrolysis (Messing et al, 1993; Studenikin et al., 1998; Cesar et al, 2006; Xia et al, 2008), etc. These nanostructures can also be synthesized by top-down approaches such as photolithography (Xia and Whitesides, 1998; Xia et al, 1999; Jager et al, 2000; Whitesides et al, 2001) and electron beam lithography (Maier et al., 2001 ; Maier et al, 2003; Jiao et al, 2009). Template mediation (Stupp et al., 1997; Freund and Suresh, 2003; Barth et al, 2005; Liang et al, 2009; Zhang et al, 2013) and self-assembly are also used for making desired nanostructures. All these methods need special conditions like vacuum, high temperature, templates, etc. Ambient, solution state techniques to create well-defined nanostructures are a very recent area of research. An earlier report from our group shows that very long nanowires of metal can be made under ambient conditions at room temperature (Sarkar et al., 2016).

The present invention discloses hydrophilic-hydrophobic nanostructured grassland-like surfaces for efficient atmospheric water capture.

SUMMARY OF THE INVENTION

The present invention relates to hydrophilic-hydrophobic patterned metallic nanobrushes resembling grassland-like surface for efficient atmospheric water capture composed of nanowires which in turn are made of nanoparticles of less than 20 nm in diameter, together making micrometer long bristles, grown in air by droplet deposition. In one embodiment, the present invention describes the synthesis of one dimensional (ID) silver nanowires (Ag NWs), which can also be named as Ag nanobrushes due to their brush-like morphology, under an ambient condition at room temperature. Ag nanobrushes were made using electrospray deposition of an aqueous solution of silver acetate (AgOAc) on a stainless steel mesh or TEM grid.

In other embodiment, the present invention shows modification of as-synthesized nanobrushes into a patterned surface with specific hydrophilic regions on a hydrophobic background. The solution of a fluorothiol (FT) namely, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- Heptadecafluoro-l-decanethiol is coated over the as-synthesized nanobrushes to make it as superhydrophobic surface. Further hydrophilic zones are created on the superhydrophobic Ag nanobrushes by electrospraying AgOAc solution using nESI on the modified Ag nanobrushes for the purpose of atmospheric water capture.

In another preferred embodiment, the present invention relates to synthesis of hydrophilic-hydrophobic patterned Ag nanobrushes with three distinct regions- (i) the Ag-core, (ii) hydrophobic coating on the Ag-core and (iii) tiny hydrophilic regions (Ag NPs) on the hydrophobic background. Wherein, Ag core gives the strength and nanostructure to the brushes, while the FT coating creates the hydrophobic background. Further, Ag NPs deposited all over the nanobrushes and these Ag nanoparticles, embedded in the FT layer, act as hydrophilic zones, known to be responsible for condensation of atmospheric humidity.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts SEM images of Ag nanobrushes synthesized by electrospray deposition A) Large area SEM image of as-synthesized Ag nanobrush on stainless steel wire mesh and B) higher magnification SEM image of the same.

Figure 2 depicts TEM images of Ag nanobrushes after 4 h deposition. A) TEM image showing ID Ag nanobrushes in a single square of a TEM grid, and B) higher magnification TEM image of the same, showing the uniformity and one dimensionality of the nanobrushes.

Figure 3 shows schematic representations of A) as-synthesized, B) FT coated, C) hydrophilic- hydrophobic patterned Ag nanobrushes. Inset in B shows the chemical structure of the FT, D) Schematic of atmospheric water condensation on the hydrophilic zones of the patterned Ag nanobrushes, E) Schematic representation of the coalescence of the small water droplets to form a bigger droplet followed by rolling off the hydrophobic surface. Figure 4 depicts SEM images of Ag nanobrush before (A) and after (B) FT coating. Change in the contrast of the image B proves the presence of an organic matrix. C) TEM image of Ag nanobrush after electrospray coating of FT, showing the intact morphology of the brushes after coating. The inset shows EDS spectrum taken from the same, showing presence all the expected elements. D) TEM image of the same at higher magnification, showing the presence of Ag NPs and FT coating.

Figure 5 shows optical images (A-C) of water droplet bouncing off from the FT coated Ag brush substrate while another water droplet is stranded on the bare stainless steel wire mesh proving the slippery nature of the Ag nanobrush coated area. D) Contact angle of a water droplet on a normal stainless steel wire mesh (>125°) and on a FT-coated Ag nanobrush surface (>170°) proving the superhydrophobic nature of the later.

Figure 6 shows A) TEM image of hydrophilic-hydrophobic patterned Ag nanobrushes showing three different regions indicated as Ag core, hydrophobic region, and hydrophilic regions. B) Schematic representation of atmospheric water capture by the metallic grassland with hydrophilic-hydrophobic pattemed surface. C) Schematic representation of the three distinct regions of the patterned surface which corresponds to the TEM image shown in A.

Figure 7 shows optical images showing atmospheric water capture on normal stainless steel wire mesh (A, B) and hydrophilic-hydrophobic patterned Ag nanobrush (C, D) after 60 and 120 seconds, respectively at 40% relative humidity.

Figure 8 A) Optical photograph of the water collection set-up. Inset shows a photograph of the hydrophilic-hydrophobic patterned surface over a 2x2 cm2 area. Each ESD results in a 5 mm dia dark colored disk indicating the growth of NWs. This process was repeated multiple times to cover the 2x2 cm2 area. B) Optical photograph of the surface just after switching on the peltier cooler, C) Zoomed in photograph of the surface showing condensed water droplets on it and dripping of water at the bottom of the surface. D) Optical photograph of the collected water in a 2 mL vial.

Figure 9 Prototype for the atmospheric water capture experiment.

Figure 10 shows A), B) SEM images of the superhydrophobic brushes after the water capture experiment, showing that the morphology is intact, C) and D) contact angle of a water droplet on the same showing that the superhydrophobic nature of the surface is also unchanged during the water capture experiments.

Referring to the drawings, the embodiments of the present invention are further described. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated or simplified for illustrative purposes only. One of ordinary skill in the art may appreciate the many possible applications and variations of the present invention based on the following examples of possible embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various forms. The figures are not necessarily to scale; some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention.

The present invention relates to hydrophilic-hydrophobic patterned grassland-like surface for efficient atmospheric water capture. The surfaces were created from silver nanowires (AgNWs), synthesized under an ambient condition at room temperature. Ag nanobrushes were made using ambient droplet sprays of an aqueous solution of silver acetate (AgOAc). Ambient droplet spray is a process in which charged droplets can be made using electrospray ionization. These charged droplets containing metal and solvated metal ions may be directed towards a grounded surface to make nanomaterials such as, metal NPs. A slight modification of the deposition substrate can have a huge impact in the dimensionality of the product. For example, introduction of a mask in-between the electrospray tip and the substrate can produce ID NWs. A recent report from our group discussed the various aspects of ID NWs by electrospray ionization (Sarkar et al, 2016). For electrospray deposition, a homemade nESI source was made by pulling a borosilicate glass capillary (0.86 mm inner diameter, 1.5 mm outer diameter, and 10 cm length) into two. The pulling was performed in a controlled fashion in order to achieve an inner diameter of approximately 15 μηι at the tip. These tips were used as nanoelectrospray (nESI) source in all our deposition experiment. For the electrospray process, a nESI tip was filled with a 10 mM aqueous solution of AgOAc using a micro injector and a potential in the range of 2-2.5 kV was applied to it through a platinum wire (0.1 mm diameter) electrode. The spray plume coming out of the tip was then collected on a grounded stainless steel wire mesh of 50 μιτι mesh size. For TEM measurements Ag nanobrushes were made on top of an empty TEM grid (without carbon coating). A typical deposition current of 100-110 nA was maintained during the deposition. The spray plume containing Ag and solvated Ag ions got deposited, neutralized and oriented to form ID nanowires (NWs). SEM images show that these NWs were made of Ag nanoparticles (NPs) oriented in a head-on position. Figure 1 and 2 show SEM and TEM images of the as-synthesized Ag brush.

For water capture, the as-synthesized nanobrushes were modified to make a patterned surface with specific hydrophilic regions on a hydrophobic background. Figure 3A shows a schematic representation of the Ag brush on a stainless steel wire mesh. Then a solution of a fluorothiol (FT) namely, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadecafluoro-l-decanethiol in DCM and AcN mixture was electrosprayed on the Ag brushes. In this process, the sulfur group loses the proton and attaches to Ag, the feasibility of this process can be described by the formation of a stronger metal-sulfur bond. Figure 3B shows a schematic of the FT coated Ag nanobrushes in which the black spheres represent Ag and the yellow spheres represent sulfur atoms. The inset shows the chemical formula of the FT used for coating. These nanobrushes became superhydrophobic due to FT coating. From the earlier reports it is known that the hydrophilic-hydrophobic patterning of the surface makes it more efficient in atmospheric water capture (Zheng et al., 2010; Miljkovic et al, 2013). Due to this reason, hydrophilic-hydrophobic patterning of these nanobrushes was achieved by electrospray deposition of Ag on the SH nanobrushes, to achieve better efficiency of water capture. Figure 3C shows the schematic of the nanobrushes with patterned surfaces. These nanobrushes were used for atmospheric water capture. Figure 3D shows the collection process schematically. Water is condensed on the hydrophilic area of the nanobrushes. Then coalescence of the small droplets happens and once a droplet becomes big enough, it rolls off from the surface and a second cycle starts. Figure 3E shows the droplet coalescence schematically, where small droplets 1 and 2 come together to form a bigger droplet (1+2) and it rolls of from the nanobrushes due to the hydrophobic background.

Figure 4A is a SEM image of the as-synthesized Ag nanobrush on a stainless steel wire mesh. It shows thin ID growth of Ag forming a NW structures giving grassland-like morphology. Figure 4B shows SEM image of the same after FT coating. The change in contrast is due to the coating of a non-conducting layer of FT on the metal. The image proves that after electrospray coating, the morphology of the nanobrushes was intact. Figure 4C and D are TEM images of the FT coated brush at different magnifications. Figure 4C also proves brush-like morphology of FT-coated Ag nanobrushes. Inset in Figure 4C shows an EDS spectrum taken from these brushes showing the presence of all the expected elements (Ag, S, and F). Figure 4D shows a high magnification TEM image of the same, showing the presence of Ag NPs in the brush in a FT matrix. The darker dots represent Ag NPs where the lighter part is the organic FT matrix.

During the electrospray deposition of FT on Ag nanobrush, some of the Ag NPs coalesce with each other, making a strong core inside. This metallic core gives strength to the brushes, making them more resistant toward any mechanical strain.

Figure 5A-C show optical images of a water droplet bouncing off from the FT coated Ag brush substrate while another water droplet is stranded on the bare stainless steel wire mesh. This proves that the FT coating on the Ag brushes made them hydrophobic in nature. The contact angle of a water droplet on the FT-coated Ag brushes was measured. Figure 5D shows contact angle measurement of a water droplet on stainless steel wire mesh before (normal wire mesh) and after modification (Ag brushes with FT coating). Contact angle of the water droplet was measured to be >125° in the case of normal mesh indicating that the normal stainless steel surface is hydrophobic (90°<6c< 150°). Measurement of resting contact angle was not possible for the superhydrophobic surface as it was very slippery for the droplet to sit on it. Hence the contact angle was measured when the water droplet was touching the surface. These measurements proved that the surface became superhydrophobic.

The patterned hydrophilic protrusions on a waxy hydrophobic surface ('wettability patterns'), present on the hardened forewings (elytrons) of Stenocara beetles, enable these insects to capture water from fog and survive in the Namib Desert, one of the most arid areas on this planet Earth. Mimicking such patterned surfaces using sophisticated synthetic procedures have been attempted in recent the past for atmospheric water capture. Here, we show an ambient room temperature technique to create such a patterned surface. Figure 6A shows a TEM image of the hydrophilic-hydrophobic patterned Ag nanobrushes with three distinct regions- (i) the Ag-core, (ii) hydrophobic coating on the Ag-core and (iii) tiny hydrophilic regions (Ag NPs) on the hydrophobic background. Ag core gives the strength to the brushes, while the FT coating creates the hydrophobic background. Further Ag deposition on this resulted in Ag NPs decoration all over the nanobrushes. These Ag NPs, embedded in the FT layer, act as hydrophilic zones, known to be responsible for condensation of atmospheric water. A schematic illustration of atmospheric water capture by these hydrophilic-hydrophobic patterned nanobrushes is shown in Figure 6B. Figure 6C, on the other hand, shows a schematic representation of the material design with three distinct regions mentioned above. A 2 cm x 2 cm surface covered by these patterned nanobrushes was created and used for water capture experiments.

A 2 cm x 2 cm SS wire mesh covered by these patterned NWs was created and used for water capture experiments described in the following sections. Evaluation of humidity condensation was performed using this surface mounted on a Peltier cooler, which was then videographed using a microscope. Two experiments, one control (with normal stainless steel mesh) and another with the prepared surface, were performed to test the efficiency of the nanostructured material for atmospheric water capture. In both the experiments, the surface being examined was carefully mounted on a Peltier cooler, using silver paste as glue, so that it remained in adequate contact with the cooling stage. The entire arrangement was placed atop the viewing stage of an inverted fluorescence microscope (Leica), in a controlled room with 40% relative humidity and 28°C temperature (the dew point at this condition approximately 13°C). The arrangement was made for illumination of the surface being examined, for the purpose of microscopy. Time-lapse optical microscopy of the stainless steel mesh as well as the prepared surface upon exposure to cool humid air was performed to monitor droplet nucleation and condensation. The temperature of the surface under examination was maintained at 12°C, measured with a thermocouple. Figure 7A and B in the patent file show the optical images of a normal stainless steel wire mesh after 60 and 120 seconds of collection, respectively. Condensation of water droplets was seen on the wire mesh. Figure 7C and D show the optical images of condensation of water on the stainless steel wire mesh containing superhydrophobic Ag nanobrush with hydrophilic protrusions. It is seen that the amount of water captured in this case is much larger in comparison to the normal wire mesh. In a time span of 2 minutes, a large volume of water was captured on the brushes, even though the humidity was less and no water vapor was forcefully passed over the surface during the experiment. The video clearly shows nucleation of tiny water droplets on the pattemed NWs followed by fusion of them to bigger droplets. Once the droplet is larger in size, it rolls off the surface because of its superhydrophobic nature.

Transport of the condensed water is a crucial criterion of any atmospheric water capture material. Hence, we calculated the water collection rate of the surface on a 2x2 cm2 area considering all the parameters like, condensation rate, transport of the collected water, etc. Figure 8A shows an optical photograph of the total set up where the hydrophilic-hydrophobic pattemed NWs containing SS wire mesh was firmly mounted (the black square surface) on a peltier cooler, using a carbon tape. Carbon tape was used in this case, instead of silver paste, for better transport of the collected water. Inset of Figure 8 A shows photograph of the surface. A 12 V DC fan was used for cooling the hot side of the peltier cooler. Temperature of the surface was measured and kept constant (7.5°C) during the experiment.

The above experiment was performed inside an air-conditioned room where the relative humidity was 48% and the ambient temperature was 26°C. There was no forced airflow. Figure 8B shows the formation of water droplets on the hydrophilic-hydrophobic patterned nanobrushes, just after switching on the peltier cooler. Figure 8C shows a zoomed-in view of the surface showing condensed water droplets on it. In the above experiment, 3.75 mL of water was collected in 13 h. If we convert the water collection to litre/day/m2 area, it comes to 7.9 L. Figure 8D shows an optical photograph of the collected water in a 2 mL vial.

For the next set of experiments, we designed a prototype to evaluate the water capture efficiency of the surface in presence of air flow. Figure 9 shows a schematic of the prototype. In these experiments, a 12V DC (air flow speed of 2.55 m/s) fan was used to blow atmospheric air towards the cold hydrophilic-hydrophobic pattemed surface. Two sets of experiments were performed with this prototype; i) inside an air-conditioned room (at lower humidity), ii) outside the lab, under ambient conditions. Conditions and data collected from these experiments are described here. In the first set of experiments, surface temperature and average relative humidity were 8°C and 58%, respectively. The water collection efficiency was calculated as 26.8 liter/day/m2. In the second set of experiments, the temperature of the surface was kept the same and average relative humidity was- 87%. In this case the water collection efficiency was calculated as 56.5 liter/day/m2. This is the highest water collection reported till date by any surface.

For long-term use of this substrate, stability of the brushes is an important factor. Reusability and the morphology of the surface were checked after the water capture experiment. Figure 10A and B show SEM images of the hydrophilic-hydrophobic patterned Ag nanobrushes after 5 cycles of water capture. The images show that the morphology of the brushes is intact after water capture. Contact angle of water on the surface, before and after water capture was also measured to ensure the retention of surface properties. Figure IOC and D show contact angle measurements of a water droplet on the superhydrophobic Ag brush substrate before and after the water capture experiment, respectively. Contact angle was found to be the same in both the cases, proving that the nature of the surface is the same after dew collection. These data prove that a large amount of water can be collected on the superhydrophobic metallic grassland, without any damage to the surface and its properties.

Thus the superhydrophobic structures were characterized using electron microscopy. Super hydrophobicity of the structures was confirmed by contact angle measurements. Hydrophilic zones were created on the superhydrophobic Ag nanobrushes, for the purpose of atmospheric water capture. This was achieved by spraying AgOAc solution by nESI on the modified Ag nanobrushes. These surfaces were tested for atmospheric water capture by cooling them below the dew point at a particular relative humidity and the phenomenon of water condensation was observed under an optical microscope. It was seen that water droplets were condensed on it at a much faster rate than on a normal stainless steel wire mesh. Initial calculation based on microscopic image analysis during water capture suggests capacities as high as 30 L h_1m"2, enabling efficiently capture atmospheric water even at low relative humidity.

Claims

We Claim:
1. A nanostructured surface, composed of individually patterned hydrophilic-hydrophobic regions on micrometer long brushes, with each bristle composed of nanoparticles, grown in air using ambient electrospray deposition, for capturing atmospheric humidity, comprising a. a core portion of metallic nanobrush
b. a coating layer portion covering the metallic nanobrush, making it superhydrophobic and
c. metallic nanoparticles deposited over the coated metallic nanobrushes function as hydrophilic protrusions on a hydrophobic background.
2. The hydrophilic-hydrophobic nanostructured surface of claim 1, wherein the surface is grown on metal wire meshes including but not limited to stainless steel, copper, brass and also on silicon.
3. The hydrophilic-hydrophobic nanostructured surface of claim 1, wherein the metallic nanobrush is made from any metallic NPs selected from Ag, Au, Pd, Pt, Ni, Fe and their alloys grown from droplets of their salt solutions.
4. The hydrophilic-hydrophobic nanostructured surface of claim 1, wherein the metallic nanobrush is chemically functionalized with 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluoro-l -decanethiol or similar molecules producing low surface energy surfaces.
5. The hydrophilic-hydrophobic nanostructured surface of claim 1, wherein the hydrophilic metallic NPs deposited over superhydrophobic regions are selected from Ag, Au, Pd, Pt, Ni, Fe and their alloys grown from droplets of their salt solutions.
6. A method for preparing hydrophilic-hydrophobic patterned silver nanobrushes grown in air using electrospray deposition for capturing atmospheric humidity, comprise the following steps
a. electrospray deposition of an aqueous solution of silver acetate on a stainless steel wire mesh forming silver nanobrush under ambient conditions at room temperature. b. chemically functionalize with 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-l- decanethiol which coats the silver nanobrush, turning it into a superhydrophobic surface.
c. silver NPs deposition over the resulted superhydrophobic silver nanobrush, to act as hydrophilic zones, responsible for condensation of atmospheric water.
7. The hydrophilic-hydrophobic nanostructured surface of claim 1 and 6, wherein the surface has a capturing efficiency of 30 L h_1m"2 or more at a relative humidity of 40%.
8. The hydrophilic-hydrophobic nanostructured surface of claim 1 and 6, wherein larger area pattern on m2 dimension of atmospheric water capturing surface is made with multiple spray tips.
9. The hydrophilic-hydrophobic nanostructured surface of claim 1 and 6, wherein the nanostructured device along with a cooling device is suitable for capturing atmospheric humidity.
10. The hydrophilic-hydrophobic nanostructured surface of claim 1 and 6, wherein the nanostructured surface grown over large area resembles grassland-like morphology.
11. A surface as claimed in claims 1-6, which can capture solvent vapors by functionalizing the nanobrushes.
12. Method of growing such brushes with hydrophobicity brought about by molecules similar to 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-l-decanethiol.
13. Method of growing such brushes on differently processed surfaces such as electrospun membranes made of polymers, plastics, oxides, graphene, etc.
14. A method of growing brushes for capturing atmospheric humidity as claimed in claims 1 and 6, where the growth of the hydrophilic layer of nanoparticles is by methods other than electrospray deposition, such as dip coating, solution phase deposition, thermal evaporation, etc.
15. A method of growing brushes as claimed in claims 1 and 6, by a combination of methods, one step being electrospray deposition.
PCT/IN2017/050621 2016-12-29 2017-12-28 Patterned metallic nanobrushes for capture of atmospheric humidity WO2018122872A1 (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100143741A1 (en) * 2006-09-20 2010-06-10 The Queen's University Of Belfast Method of coating a metallic article with a surface of tailored wettability

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100143741A1 (en) * 2006-09-20 2010-06-10 The Queen's University Of Belfast Method of coating a metallic article with a surface of tailored wettability

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DEPANJAN SARKAR ET AL.: "Metallic Nanobrushes Made using Ambient Droplet Sprays", ADV. MATER., vol. 28, no. 11, 20 January 2016 (2016-01-20), pages 2223 - 2228, XP055512818, Retrieved from the Internet <URL:https://doi.org/10.1002/adma.201505127> *
MELODY CHEUNG ET AL.: "Raman Analysis of Dilute Aqueous Samples by Localized Evaporation of Submicroliter Droplets on the Tips of Superhydrophobic Copper Wires", ANAL. CHEM., vol. 88, no. 8, 19 April 2016 (2016-04-19), pages 4541 - 4547, XP055512850, Retrieved from the Internet <URL:doi: 10.1021/acs.analchem.6b00563> [retrieved on 20160331] *
XIN HENG ET AL.: "Branched ZnO Wire Structures for Water Collection Inspired by Cacti", APPL. MATER. INTERFACES, vol. 6, no. 11, 11 June 2014 (2014-06-11), pages 8032 - 8041, XP055512851, Retrieved from the Internet <URL:DOI: 10.1021/am4053267> [retrieved on 20140205] *

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