Patent Application
20240367354
The present invention relates, in general terms, to methods of fabricating curved 2D membranes and the membranes thereof.
Two-dimensional (2D) material-based thin films such as graphene oxide (GO) paper, zeolite nanosheet membranes, metal oxide nanosheets, and transition metal carbides/carbonitrides (MXenes) offer a wide range of applications for energy storage, stimuli-responsive membranes, acoustic transducing, flexible electronics, and actuators. In most applications, flat films and membranes are used. However, curved shapes such as hyperbolic paraboloid surfaces can be beneficial for new acoustic devices, self-cleaning membranes, and soft robotics due to their exceptional mechanical properties and their capability to switch between two equilibrium states, unturned and inverted shapes. One of the targeted application areas of such membranes can be the design of new acoustic diaphragms. For instance, the simulated acoustic diaphragm of a hyperbolic paraboloid shape provides more uniform directivity and improved power response. Furthermore, metamaterials with structural bistability can be used for the construction of stimuli-responsive elements for soft robotics. Hyperbolic paraboloid shaped elastomeric materials were used to mimic fish motion.
However, at this moment, there is lack of approaches and materials for forming curved 2D metamaterials. Various assembly methods such as vacuum filtration, evaporation, spin coating, and casting have been employed to prepare flat 2D membranes only. Curved 2D shapes can be prepared by pressing the flat film into a desired curved geometry by mechanical force. For example, curved diaphragms are prepared by “crimping” GO-based flat films. However, applying a mechanical force has the drawback of stretching the original flat film, which leads to internal stress accumulation, and affecting the film microstructure. Furthermore, the mechanical deformation of flat films is only suitable for creating simple shapes with low curvatures. Among other materials, elastomers were successfully used for the formation of hyperbolic paraboloid surfaces.
For example, a soft-robotic ray mimic can be fabricated using an elastomer in a saddle shape. However, elastomers have a bulk structure, relatively inert surface, a lack of functionality, and a limited application area. In contrast, the members of the 2D materials' family with their high surface-to-volume ratio, flexibility, tunable or controllable electronic and optical properties, are shown to be multifunctional materials with a broad technological area from membrane technology to flexible electronics and biomedical applications. Thus, curved 2D materials along with or in combination with soft matter can give us new functional materials that can be used to construct footprint devices with switchable electronic and optical properties as well as the capability to self-cleaning and antifouling.
It would be desirable to overcome or ameliorate at least one of the above-described problems.
The present disclosure relates to a fast and easy approach for constructing, among others, 2D saddle-shaped GO membranes with controllable curvature and thickness. The inventors formulated, and experimentally showed the feasibility of the presently disclosed method to prepare hyperbolic paraboloid 2D membranes with controllable thicknesses and curvatures. The invention is based on the development of new porous templates for the self-assembly of 2D nanosheets. The self-assembly provides the formation of a highly oriented lamellar texture. The thickness and curvature can be controlled with nanoscale precision by adjustment of self-assembly conditions. The new material demonstrates a highly ordered nanostructure typical for flat 2D analogous. Its robustness and ability to retain curved shapes are achieved due to the arrangement and stacking of nanosheets of GO. The method is adjustable such that other 2D materials such as metal dichalcogenides, MXenes, and 2D metal oxides can be used.
The present invention provides a method of fabricating a curved 2D membrane, comprising:
In some embodiments, the curved polymer template is characterised by a hyperbolic paraboloid curvature.
In some embodiments, the curved polymer template is characterised by a curvature with a hyperbolic paraboloid surface function:
wherein k is a curvature coefficient.
In some embodiments, k is a value from about 0.1 to about 0.6.
In some embodiments, the curved polymer template is saddle shaped.
In some embodiments, the curved polymer template is formed from a thermoplastic polymer.
In some embodiments, the curved polymer template is formed from polyethersulfone (PES).
In some embodiments, the curved polymer template is fabricated by:
In some embodiments, the polymer solution is characterised by a polymer concentration of about 10 wt % to about 30 wt %.
In some embodiments, the non-solvent is an aqueous medium.
In some embodiments, the immersion step is performed for at least 5 min.
In some embodiments, the immersion step is performed at a temperature of about 0° C. to about 70° C.
In some embodiments, the immersion step is performed at a temperature of about 25° C.
In some embodiments, the method further comprises a step of air drying the coagulated polymer layer before separating it from the corresponding curved template.
In some embodiments, the curved polymer template is characterised by a pore size of about 10 nm to about 50 nm.
In some embodiments, the curved polymer template is characterised by a pore size of about 20 nm.
In some embodiments, the curved polymer template is characterised by a thickness of about 50 μm to about 400 μm.
In some embodiments, the support comprises:
In some embodiments, the porous surface is characterised by a pore size of about 0.5 mm to about 2 mm.
In some embodiments, the base further comprises a stand, the porous surface provided on an end of the stand.
In some embodiments, the curved polymer template is positionable on the porous surface of the base.
In some embodiments, the curved polymer template is sandwiched between the base and the cap.
In some embodiments, the support is 3D printed.
In some embodiments, the support is configured to fit into a Buchner funnel.
In some embodiments, the flow step comprises filtering the solution of 2D material through the curved polymer template.
In some embodiments, the filtration is performed under a vacuum.
In some embodiments, the solution of 2D material comprises a 2D material selected from graphene oxide (GO), metal dichalcogenides, MXenes, 2D metal oxides, their combination, derivatives and analogs thereof.
In some embodiments, the solution of 2D material is characterised by a 2D material concentration of about 1 mg/ml to about 10 mg/mL.
In some embodiments, the method further comprises drying the 2D multilayers on the curved polymer template under air, N2 or an inert gas.
In some embodiments, the drying step is performed at a temperature of about 15° C. to about 90° C.
In some embodiments, the separation step comprises peeling the 2D multilayers from the curved polymer template.
In some embodiments, the curved 2D membrane is characterised by a thickness of about 4 μm to about 20 μm.
In some embodiments, when the 2D material is GO, the curved 2D membrane is characterised by an interlayer distance of about 0.85 nm to about 0.95 nm.
In some embodiments, when the 2D material is GO, the curved 2D membrane is characterised by an interlayer distance of about 0.89 nm.
The present invention also provides a curved 2D membrane fabricated by the method as disclosed herein.
The present invention also provides a curved 2D membrane comprising a 2D material selected from graphene oxide (GO), metal dichalcogenides, MXenes, 2D metal oxides, their combination, derivatives and analogs thereof;
Embodiments of the present invention will now be described, by way of non-limiting example, with reference to the drawings in which:
Hyperbolic paraboloid surfaces or saddle-shaped materials can exist in two equilibrium states when the saddle shape reverses on itself and, therefore, can be used as structural elements of new stimuli-responsive and shape-changing materials. Herein, a fast and easy approach to the self-assembly of two-dimensional (2D) nanosheets along or with a polymer to form curved interfaces is described. The method involves computer-aid designing, 3D printing, and casting curved templates for self-assembly of two-dimensional (2D) nanosheets. As an example, the feasibility of this method for self-assembly of graphene oxide flakes, and graphene oxide flakes with polymers is shown, though it can be expanded to include the whole family of 2D materials. The prepared free-standing saddle-shaped 2D membranes showed highly ordered nanostructure, typical for flat 2D multilayered materials. The physical organic preparation conditions was optimised to construct robust two-dimensional membranes with nanostructured architecture and controllable thickness and curvature. Such membranes can be used as bistable structures for the construction of new acoustic devices, flexible electronics, and membranes with self-cleaning and antifouling properties.
The present invention provides a method of fabricating a curved 2D membrane, comprising:
Comparing to other methods of the formation of curved 2D materials the presently disclosed method has the following advantages:
The method of formation of layered active shape changing materials is low-cost, and is an easily up-scalable preparation technique for bistable structures that can be used for the construction of new acoustic devices, flexible electronics, and membranes with self-cleaning and antifouling properties. The technology involves computer-aid design, 3D printing, and casting curved templates for self-assembly of two-dimensional (2D) nanosheets in order to form robust two-dimensional membranes with nanostructured architecture and controllable thickness and curvature. The thickness and curvature of 3D-printed curved porous and non-porous insert for the fabrication of porous polymeric templates with controlled porosity and curvature can be controlled with nanoscale precision by adjustment of self-assembly conditions. The material demonstrates a highly ordered nanostructure typical for flat 2D analogs. The porous saddle-shaped templates for the self-assembly of 2D nanosheets such as hyperbolic paraboloid surfaces can control the self-assembly process. This fast and easy construction of curved 2D membranes can be integrated in devices (acoustic diaphragms, soft robotics, membranes, etc.). Improvements were further made to the filtration method to increase the thickness uniformity of the films such that free-standing films can retain the designed shape.
In some embodiments, the curved polymer template is characterised by a hyperbolic paraboloid curvature. In some embodiments, the curved polymer template is characterised by a curvature with a hyperbolic paraboloid surface function:
wherein k is a curvature coefficient. In some embodiments, k is a value from about 0.1 to about 0.6. In other embodiments, k is a value from about 0.1 to about 0.5, about 0.1 to about 0.4, about 0.2 to about 0.4, or about 0.3 to about 0.4.
In some embodiments, the curved polymer template is saddle shaped.
As the curved 2D membrane is formed on the curved polymer template, the curved 2D membrane also adopts a hyperbolic paraboloid curvature.
In some embodiments, the method of fabricating a curved 2D membrane, comprises:
In some embodiments, the curved polymer template is formed from a thermoplastic polymer. In some embodiments, the curved polymer template is formed from polyethersulfone (PES). In other embodiments, the curved polymer template is formed from a nonsolvent induced phase inversion method. Phase inversion or phase separation is a chemical phenomenon performed by removing the solvent from a liquid-polymer solution, leaving a porous, solid membrane. This may give a curved polymer template with a smooth surface.
Phase inversion can be carried out by reducing the temperature of the solution, by immersing the polymer solution into anti-solvent, exposing the polymer solution to a vapor of anti-solvent, and evaporating the solvent in atmospheric air or at high temperature. The rate at which phase inversion occurs and the characteristics of the resulting membrane are dependent on several factors, including solubility of solvent in the anti-solvent, insolubility of the polymer in the anti-solvent, and temperature of the anti-solvent.
In some embodiments, the curved polymer template is fabricated by:
In some embodiments, the polymer solution is characterised by a polymer concentration of about 10 wt % to about 30 wt %. In other embodiments, the concentration is about wt % to about 25 wt %, about 10 wt % to about 20 wt %, or about 10 wt % to about wt %.
In some embodiments, the polymer solution comprises dimethylacetamide as a solvent. Other solvents that may be used include, tetrahydrofuran, 1,4-dioxane, chloroform, dichloromethane, and chlorobenzene.
In some embodiments, the polymer solution is degassed. The degassing can be performed for at least 12 h, at least 16 h, or at least 24 h.
In some embodiments, the non-solvent is an aqueous medium. The aqueous medium may be water. In other embodiments, the non-solvent is an alcohol, such as methanol, ethanol, propanol or butanol.
In some embodiments, the immersion step is performed for at least 5 min.
In some embodiments, the immersion step is performed at a temperature of about 0° C. to about 70° C. In this regard, the non-solvent is provided as a bath within this temperature range. In some embodiments, the immersion step is performed at a temperature of about 10° C. to about 70° C., about 10° C. to about 60° C., about 10° C. to about 50° C., about 10° C. to about 40° C., about 10° C. to about 30° C., or about 10° C. to about 20° C. In some embodiments, the immersion step is performed at a temperature of about 25° C.
In some embodiments, the method further comprises a step of air drying the coagulated polymer layer before separating it from the corresponding curved template.
In some embodiments, the curved polymer template is characterised by a pore size of about 10 nm to about 50 nm. In some embodiments, the curved polymer template is characterised by a pore size of about 20 nm. It was found that at this pore size range, the 2D materials are substantially retained on the curved polymer template in order to form the curved 2D membrane while allowing the solvent to flow through.
In some embodiments, the curved polymer template is characterised by a microporous morphology in its sublayer and by sub-micron pores in its surface layer. In some embodiments, the microporous morphology is an asymmetric structure with finger-like pores. This allows for optimal rate of solvent elimination as well as smooth surface for guided self-assembly of 2D nanosheets in highly-ordered multilayers with nanoscale precision.
In some embodiments, the curved polymer template is characterised by a thickness of about 50 μm to about 400 μm. In some embodiments, the curved polymer template is characterised by a thickness of about 50 μm to about 350 μm, about 50 μm to about 300 μm, about 50 μm to about 250 μm, about 50 μm to about 200 μm, or about 100 μm to about 200 μm.
The corresponding curved template used to form the curved polymer template may be characterised by a hyperbolic paraboloid curvature. For example, the corresponding curved template may be characterised by a curvature with a hyperbolic paraboloid surface function:
wherein k is a curvature coefficient. In some embodiments, the corresponding curved template is saddle shaped. In this regard, the curved profile is thus transferred to the curved polymer template.
In some embodiments, the corresponding curved template comprises a base and a cap. The cap fits over the base. The cap and/or the base comprises the curved profile as disclosed above. The cap is engageable with the base. For example, the cap may be frictionally engageable with the base such that the cap is not displaceable when a solvent is poured over the curved template. In this regard, the cap is sized such that its inner diameter is at least 0.3 mm larger than the outer diameter of the base, or at least 0.5 mm. The cap may comprise a centrally positioned hole. In use, the polymer template is positioned between the cap and the base when the cap is fitted onto the base. As a hole is present, the solution of 2D material can access the polymer template. The cap may further comprise inwardly formed edge. The inwardly formed edge allows for better engagement of the polymer template and/or the base. The inwardly formed edge may have a thickness of at least about 3 mm, or about 5 mm. The cap may comprise a flange at its bottom end. The flange may have a thickness of more than 1 mm, or about 1.5 mm.
The base may comprise a porous surface. The porous surface may comprise a plurality of holes. The porous surface may be located within the curved profile. The plurality of holes may be arrayed. The cap may further comprise a border, the plurality of holes being contained within the border. The border may have a thickness of about 1 mm to about 5 mm, or about 2 mm.
In combination, the polymer template is held between the cap and the base. A solution of 2D material can flow from the hole of the cap to the polymer template and away from the polymer template via the plurality of holes in the base. In some embodiments, the curved polymer template is positionable on the porous surface of the base. In some embodiments, the curved polymer template is sandwiched between the base and the cap.
Accordingly, in some embodiments, the corresponding curved template or support comprises:
The base may be sized such that it is about 0.2 mm to about 1 mm smaller than the cap. This allows a smooth but tight fit between the base and the cap such that the curved polymer template and/or the curved 2D membrane will not be distorted or torn during assembly or removal. In other embodiments, the gap is about 0.2 mm to about 0.8 mm, about 0.4 mm to about 0.8 mm, about 0.4 mm to about 0.6 mm, or about 0.5 mm.
In some embodiments, the porous surface is characterised by a pore size of about 0.5 mm to about 2 mm. In some embodiments, the pore size is about 0.5 mm to about 1.5 mm, or about 0.5 mm to about 1 mm. In some embodiments, the pore size is less than 1 mm, or about 0.7 mm.
In some embodiments, the base further comprises a stand, the porous surface provided on an end of the stand. The stand may be a flange at a bottom end of the base. The flange may have a thickness of more than 3 mm, or about 2 mm.
In some embodiments, the support is 3D printed.
Any commercially available polymeric, metallic and ceramic inks for 3D printing can be used to form the support.
In some embodiments, the support is configured to fit into a Buchner funnel.
In some embodiments, the flow step comprises filtering the solution of 2D material through the curved polymer template. During this process, the 2D material may self assemble to form a film. The 2D material may self assemble into a multi-layered morphology.
In some embodiments, the filtration is performed under a vacuum.
In some embodiments, the solution of 2D material comprises a 2D material selected from graphene oxide (GO), metal dichalcogenides, MXenes, 2D metal oxides, their combination, derivatives and analogs thereof.
The solution of 2D material may further comprise other components such as cellulose derivatives, chitosan, polyethyleneimine, and/or polyacrylonitrile fibers. By mixing these fillers with the 2D materials, a 2D composite membrane may be formed, which provides further additional advantages.
In some embodiments, the solution of 2D material is characterised by a 2D material concentration of about 1 mg/mL to about 10 mg/mL. In other embodiments, the concentration is about 1 mg/mL to about 9 mg/mL, about 1 mg/mL to about 8 mg/mL, about 1 mg/mL to about 7 mg/mL, about 1 mg/mL to about 6 mg/mL, about 1 mg/ml to about 5 mg/mL, about 1 mg/mL to about 4 mg/mL, about 1 mg/ml to about 3 mg/mL, or about 1 mg/mL to about 2 mg/mL.
In some embodiments, the method further comprises drying the 2D multilayers on the curved polymer template under air, N2 or an inert gas.
In some embodiments, the drying step is performed at a temperature of about 15° C. to about 90° C. In other embodiments, the temperature is about 20° C. to about 90° C., about 30° C. to about 90° C., about 40° C. to about 90° C., about 50° C. to about 90° C., about 60° C. to about 90° C., or about 70° C. to about 90° C.
In some embodiments, the separation step comprises peeling the 2D multilayers from the curved polymer template.
In some embodiments, the curved 2D membrane is characterised by a thickness of about 4 μm to about 100 μm. It was found that the curved 2D membrane having this thickness range is at least able to maintain its curved morphology. In other embodiments, the thickness is about 4 μm to about 20 μm, about 6 μm to about 20 μm, about 8 μm to about 20 μm, about 10 μm to about 20 μm, about 12 μm to about 20 μm, about 14 μm to about 20 μm, or about 14 μm to about 18 μm. In some embodiments, the curved 2D membrane is characterised by a thickness of about 14 μm to about 100 μm, about 14 μm to about 90 μm, about 14 μm to about 80 μm, about 14 μm to about 70 μm, about 14 μm to about 60 μm, about 14 μm to about 50 μm, about 14 μm to about 40 μm, about 14 μm to about 30 μm, or about 14 μm to about 20 μm. In some embodiments, the curved 2D membrane is characterised by a thickness of more than 14 μm.
In some embodiments, the curved 2D membrane is characterised by a multi-layered lamellar morphology. The multilayered lamellar structure comprises layers of 2D materials stacked adjacent to each other. The interlayer distance between each layer may be about 0.6 nm to about 1 nm, or about 0.7 nm to about 0.9 nm, or about 0.89 nm. The interlayer distance between the layers was found to be consistent throughout the curvature of the curved membrane.
In some embodiments, when the 2D material is GO, the curved 2D membrane is characterised by an interlayer distance of about 0.85 nm to about 0.95 nm. In some embodiments, when the 2D material is GO, the curved 2D membrane is characterised by an interlayer distance of about 0.89 nm.
The present invention also provides a curved 2D membrane fabricated by the method as disclosed herein.
The present invention also provides a curved 2D membrane comprising a 2D material selected from graphene oxide (GO), metal dichalcogenides, MXenes, 2D metal oxides, their combination, derivatives and analogs thereof;
In some embodiments, the 2D material is GO. In other embodiments, the 2D material is GO nanosheets. The GO nanosheets may be about 7 μm to about 10 μm.
In some embodiments, the curved 2D membrane is characterised by the 2D material being self assembled. Self assembly involves molecules or entities coming together spontaneously on a surface and without guidance from an external source to be organized into large ordered domains. The self assembled layer may in some cases not interact strongly with the substrate.
Accordingly, in some embodiments, the curved 2D membrane is characterised by the 2D material being organised in large order domains. The domains may be about 10 μm to about 5000 μm, or about 100 μm to about 3000 μm. In other embodiments, the domains are larger than 5000 μm.
The presently disclosed membranes can have applications in acoustic devices, architecture constructs, lightweight materials for architecture and smart housing, soft robotics, smart sensors, smart membranes.
The technological steps for the preparation of saddle-shaped 2D membranes are illustrated in
In order to self-assemble the curved nanostructured membranes, we modified a traditionally used filtration setup for vacuum-assisted assembly of 2D multilayers. We designed curved inserts that can be added to the Buchner funnel on the top of frittered support (
To 3D design an insert, we applied the hyperbolic paraboloid surface function z=k×(x2−y2) using Autodesk AutoCAD software to draw curved models. In order to estimate the optimal geometrical parameters for the insert, we varied the curvature coefficients k between 0.2 and 0.4.
Curved porous polymeric templates for self-assembly of 2D nanosheets were prepared by nonsolvent induced phase inversion method on the top of 3D-printed nonporous template from the solution of PES. PES is a cheap and robust polymeric material traditionally used as a component of polymeric, composite, and asymmetric membranes. PES is chemically resistive, has excellent mechanical properties and processibility. Nonsolvent induced phase inversion method leads to the formation of smooth polymeric surfaces essential for the further assembly of 2D layers.
We dissolved PES granules in DMAc solvent to obtain 10-30 wt % (or 15 wt %) PES solution. Other solvents such as tetrahydrofuran, 1,4-dioxane, chloroform, dichloromethane, and chlorobenzene can also be used. To eliminate bubbles from the PES solution, we left it for 24 h to degas. 1 mL of 15 wt % PES solution was spread evenly on a dry, clean, and smooth curved surface of the modified Buechner funnel (
To form homogeneous and structured 2D layers, it is essential to form the polymeric template with optimal porosity. The porosity regulates the rate of solvent elimination from the suspensions of GO and, therefore, guides the self-assembly of 2D nanosheets.
The optimal pore size and distribution were achieved in the templates prepared at 23° C. (
It is important to demonstrate that the nanostructure of the saddle-shaped membrane is analogous to those for the flat membrane. The XRD patterns obtained for flat and curved GO membranes revealed the presence (001)-peak location at around 10° (
Finally, we revealed an optimal thickness of the GO membrane capable of keeping saddle shape. Obviously, the thickness of the curved GO membrane directly affects the ability of the free-standing membrane to keep the desired shape.
A fast and easy method of self-assembly of hyperbolic paraboloid 2D membranes is disclosed herein. A 3D-printed insert for the fabrication of porous polymeric templates with controlled porosity and curvature was developed. The polymeric template was used to guide the self-assembly deposition of highly ordered layers of graphene oxide nanosheets. The versatility of our technology offers almost unlimited design freedom for shape and structure geometry. In particular, it is shown herein that creating suitable hyperbolic paraboloid surfaces can control the self-assembly process. It is shown herein that the structure and the curvature of 2D multilayered membranes could be accurately regulated by the porosity of the polymeric template and the thickness of multilayers. The microstructure of the hyperbolic paraboloid membranes is equal to those of flat 2D membranes. The thickness of the curved membranes seems to be the critical parameter affecting the ability of the free-standing films to retain the designed shape. Improvements to the filtration method are essential to increase the thickness uniformity of the films. Further studies on the effect of curvature, thickness, and process conditions on shape retention are needed. In general, a hyperbolic-paraboloid surface was used to demonstrate the feasibility of the method to construct shaped 2D membranes. The results suggest that the proposed technology is promising for fabricating curved 2D materials for various applications.
Polyethersulfone (PES, granules, 58,000 Mw) and N, N-Dimethylacetamide (DMAc, ≥99%) were obtained from Merck. Graphene Oxide water dispersion (0.4 wt %) was received from Graphenea (USA). Inc. UV sensitive Resin (UV wavelength 405 nm) for 3D printing was purchased from ANYCUBIC. Iso-Propyl alcohol (IPA, ≥99.8%) was obtained from Fisher Scientific.
We used computer-aid-design software (Autodesk AutoCAD) and 3D printing to prepare curved inserts for the vacuum filtration setup. The designed template was exported to the stereolithography format file (STL) and sliced in Photon Workshop software). The following slicing parameters were used: layer thickness—0.05 mm; normal exposure time—2 s; off time—1 s; bottom exposure time—40 s; number of bottom layers—6. 3D printer (ANYCUBIC Photon Mono X), and Wash & Cure machine (ANYCUBIC) were used for 3D printing. After printing, the inserts were removed from the printing platform and washed with IPA for 10 mins. After air drying, the inserts were cured additionally for 5 mins.
The microscopic structure and the thickness of the PES templates and GO memebranes were observed by scanning electron microscope (SEM, Zeiss Sigma 300). Before observation, the membranes were fractured in liquid nitrogen (for cross-section) and coated with gold (˜10 nm). The average skin layer pore size of the PES templates was calculated by Image J. The curvature of the GO films was analyzed by Image J Kappa. The thin-film X-Ray Diffraction (XRD) patterns of GO film were collected by thin-film X-ray diffractometer (TF-XRD, Bruker D8 Advance) with Cu Kα radiation (λ=1.5418 Å), 0.02° increment and 1 s per step.
It will be appreciated that many further modifications and permutations of various aspects of the described embodiments are possible. Accordingly, the described aspects are intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.
Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
Throughout this specification and the claims which follow, unless the context requires otherwise, the phrase “consisting essentially of”, and variations such as “consists essentially of” will be understood to indicate that the recited element(s) is/are essential i.e. necessary elements of the invention. The phrase allows for the presence of other non-recited elements which do not materially affect the characteristics of the invention but excludes additional unspecified elements which would affect the basic and novel characteristics of the method defined.
The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10202110288S | Sep 2021 | SG | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/SG2022/050667 | 9/16/2022 | WO |
