Patent Grant
9586243
This application is the U.S. national phase of International Application No. PCT/EP2010/055748, filed 28 Apr. 2010, which designated the U.S. and claims priority to EP Application No. 09159332.7, filed 4 May 2009, the entire contents of each of which are hereby incorporated by reference.
The invention relates to a self-cleaning, self-regenerating surface structure, especially a self-cleaning, self-regenerating coating, an object provided or coated therewith, and a method for providing such surface structure or coating.
In the prior art, there are several teachings to provide “easy to clean” or self-cleaning surfaces. It is, for example, known from U.S. Pat. No. 6,660,363, US 2004/0213904 or US 2002/0016433, to provide artificial surface structures to objects which provide a self cleaning effect to the surfaces of the object.
U.S. Pat. No. 7,211,313 B2 discloses surfaces rendered self-cleaning by hydrophobic structures and a process for their production. The hydrophobic effect is achieved by elevations and depressions formed by particles secured to the surface by means of a carrier. It is proposed to use a mixture of particles and binder to form the carrier. Thus, particles are also present in deeper regions or layer of a surface coating. When particles on the surface are ablated by erosion, new particles in the carrier are exposed to regenerate the self-cleaning surface. The particles are made from silicates, doped silicates, minerals, metal oxides, silica, polymers and silica-coated metal powders. Thus, U.S. Pat. No. 7,211,313 B2 discloses self-regenerating self-cleaning surfaces. However, the self-regeneration is limited to special hydrophobic self-cleaning coatings.
The main disadvantage of the known surface structures is that no active degradation of organic material is provided. Furthermore, the adherence of ice is only reduced, however, can not be avoided to a larger extent.
It is an object of the invention to provide an improved self-cleaning self-regenerating surface.
This and further objects are achieved by the subject-matter of the independent claims. Advantageous embodiments form the subject-matter of the dependent claims.
The invention provides a self-regenerating surface structure comprising biocatalytic and/or anti-icing molecules on an exposed surface of said surface structure and biocatalytic and/or anti-icing molecules embedded in said surface structure. Preferably, the surface structure is or has a coating, wherein the coating comprises biocatalytic and/or anti-icing molecules on a surface of said coating and biocatalytic and/or anti-icing molecules embedded in said coating.
The invention especially provides a self-regenerating biocatalytic surface. Biocatalytic molecules especially mean biocatalytic active molecules that are able to be active as biocatalyst. Examples for such biocatalytic active molecules are biocatalytic active proteins such as active enzymes. Comparable molecules, especially proteins, can also be active to prevent or hinder the development of ice on the surface. Further details, advantages and examples of such biocatalytic and/or anti-icing molecules as well as surface structures provided therewith and a method for producing such surface structures are disclosed in the unpublished UK patent application GB 0808350.3 filed on 9 May 2008 by AIRBUS UK LIMITED and incorporated herein by reference.
Functional structures or molecules on a surface generally loose their activity or function when the surface is eroded or when the surface and the underlying layer of material are eroded. The invention and its preferred embodiments present several approaches to ensure the functionality of the surface independently of the erosion process. The material or coating is designed such that the functionality regenerates itself when the surface is eroded.
One advantage of the invention is the conservation of a biocatalytic functionality of an exposed or released surface in spite of a surface erosion process. The invention is especially useful, for example, on aircraft structures, surfaces of wind turbines for power generation, etc.
Preferably, the biocatalytic and/or anti-icing molecules are contained in an inner layer beneath the surface.
In an embodiment of the invention, an outer layer covers at least one inner layer, wherein both the inner and the outer layers contain biocatalytic and/or anti-icing molecules.
In an embodiment of the invention, any of the layers comprise similar further functional means enabling and/or promoting biocatalytic and/or anti-icing functions.
In an embodiment of the invention, several layers of the surface structure or coating comprise reservoirs for a liquid such as water or humidity as functional means.
In an embodiment of the invention, the embedded biocatalytic and/or anti-icing molecules are of the same kind and structure as the biocatalytic and/or anti-icing molecules that are present on the surface.
In an embodiment, the biocatalytic and/or anti-icing molecules that are present on the surface are immobilized on the surface.
In an embodiment, the biocatalytic and/or anti-icing molecules that are present on the surface are covering the surface at least partially.
In an embodiment of the invention, the biocatalytic and/or anti-icing molecules that are present on the surface are immobilized on the surface via a spacer and are coating the surface at least partially.
In an embodiment of the invention, the biocatalytic and/or anti-icing molecules are biocatalytic and/or anti-icing proteins.
In an embodiment of the invention, said biocatalytic proteins are enzymes or ribozymes.
In an embodiment of the invention, said enzymes are selected from the group consisting of amylases, proteases, lipases, cellulases, nucleases, chitinases, and mixtures thereof, of natural and/or artificial origin, preferably specifically engineered proteins.
In an embodiment of the invention, the anti-icing proteins are selected from anti-freeze proteins (AFP's) of artificial or natural origin, preferably AFP's derived from fishes, insects or plants.
In an embodiment of the invention, the biocatalytic and/or anti-icing molecules are adhered to and/or contained in a carrier material.
In an embodiment of the invention, the carrier material is selected from the group consisting of:
In an embodiment of the invention, the carrier material with adhered and/or embedded biocatalytic and/or anti-icing molecules is present in form of particles embedded in a coating matrix material.
In an embodiment of the invention, the carrier material with adhered and/or embedded biocatalytic and/or anti-icing molecules is forming the surface structure material or the coating material itself for forming or coating a surface.
In an embodiment of the invention, the surface structure or coating has inner channels and/or cavities containing the biocatalytic and/or anti-icing molecules. Especially, the biocatalytic and/or anti-icing molecules are present in a liquid contained in the inner channels and/or cavities.
In an embodiment of the invention, the coating includes a plurality of layers comprising the biocatalytic and/or anti-icing molecules. Preferably, the plurality of layers is achieved by layer-by-layer deposition
In an embodiment of the invention, the coating includes tree-like or self-similar structures of the biocatalytic and/or anti-icing molecules immobilized in a certain depth of the coating.
In an embodiment of the invention, the coating includes μ-channels and/or μ-pores for a transport and/or storage of non-linked biocatalytic and/or anti-icing molecules.
In an embodiment of the invention, the coating includes fusion proteins forming the biocatalytic and or anti-icing molecules.
According to an aspect of the invention there is provided an object having a surface coated with a coating according to the invention or according to any of the aforementioned embodiments or according a combination of several embodiments.
The object can be an aircraft, such as an aeroplane or a rotorcraft.
The object can be a vehicle, such as a land, air or water vehicle. Especially, the object can be a car, a trucks or a rail car.
The object can be a rotor, such as a wind rotor, for example of a wind power generator.
The object can be a building or a construction.
The object can be a household device or housekeeping device.
The object can be furniture.
The object can be an industrial product or industrial machine.
Further, the object can be any part of one of the aforementioned items, especially a wing, a body part or a rotor blade of an aircraft.
In an embodiment, the object has an aero- or hydro-dynamically active surface at least partially coated by the coating according to the invention or any or a plurality of its embodiments or at least partly provided with a surface structure according to any of the claims 1 to 6.
According to a further aspect, the invention is directed to a method for providing a surface structure or surface coating comprising biocatalytic and/or anti-icing molecules on an exposed surface of said surface structure or said coating and biocatalytic and/or anti-icing molecules embedded or contained in said surface structure/coating.
Preferably the method is conducted according to at least one of several variants I) to IV), defined by at least one of the following steps:
In an embodiment, step I) comprises the step a) having the following order of steps:
In an embodiment, step I) comprises the step b):
In an embodiment of the method, at least one of the steps I) and II) comprises step:
In an embodiment of the method, at least one of the steps I) and II) comprises step:
In an embodiment, the carrier material is selected from materials of the group consisting of:
In an embodiment of the method according to the invention, step II) comprises the step:
In an embodiment of the method according to the invention, step II) comprises the step:
In an embodiment of the method according to the invention, step II) comprises the step:
In an embodiment of the method according to the invention, step II) comprises the step:
In an embodiment of the method according to the invention, step III) comprises the step:
In an embodiment of the method according to the invention, step III) comprises the step:
In an embodiment, the transport of the liquid is conducted by capillary action or via micro a pump.
In an embodiment, the step IV) comprises the step:
In an embodiment, the step IV) comprises the step:
Of course, any combinations of all aforementioned embodiments of the invention are possible. Further embodiments of the invention are achieved by a combination of features of the aforementioned embodiments with any of the features as disclosed or claimed in the unpublished UK patent application GB 0808350.3 filed on 9 May 2008 by AIRBUS UK LIMITED, corresponding PCT/GB2009/050425 filed Apr. 28, 2009 and published on Nov. 12, 2009 as WO2009/136186 and corresponding U.S. National Phase application serial number 12/736,486 filed Oct. 13, 2010 and published as U.S. Publication 2011/0039066 on Feb. 17, 2011 and all of which are incorporated herein by reference.
In the following, embodiments of the invention are explained with reference to the accompanying drawings.
In the following, several embodiments of a surface structure with a coating for providing biocatalytic and/or anti-icing surfaces are presented. Details of the structure and the function of the biocatalytic surfaces have been described in the previous unpublished UK patent application GB 0808350.3 filed on 9 May 2008 by AIRBUS UK LIMITED and incorporated herein by reference. A copy of the original filed documents are enclosed to this application and form part of the description and part of the disclosure of this application. The coatings, surfaces and objects described in the following are improvements of the coatings, surfaces and objects as disclosed in this previous application.
In this previous application, several surfaces at least partly covered by biocatalytic and/or anti-icing molecules are described and shown.
Biocatalytic surfaces loose their activity when the active molecules immobilized on the surfaces are removed by erosion. According to one embodiment, a surface coating is proposed wherein biocatalytic active molecules are not only immobilized on the outermost surface but also applied in a certain depth below the surface. Thus, biocatalytic active and/or anti-icing active molecules are present within a covering layer of a certain thickness. Thus, if the outermost region of the surface with the attached active molecules is eroded, the molecules present within a deeper region are exposed and ensure the biocatalytic and/or anti-icing function. Hence, the corresponding surface remains biocatalytically active in spite of the erosion.
According to one embodiment, the functional coating is designed with a self-similar structure in deeper portions of the coating. Thus, while the outermost layer of the coating is subject to inevitable erosion, the structure and functional characteristics of the new surface remains the same as before.
These characteristics can relate to the activity of enclosed enzymes. However, the functional characteristics can also include further properties promoting or enabling the functionality of the layer such as a distributed supply of water (humidity) by several means.
In the following, different ideas to achieve self-regenerating biocatalytic and/or active anti-icing surface structures, especially, but not exclusively surface structures with coatings are described. The surface structure and/or coating can be achieved by different variants:
For simplicity, the following description refers to biocatalytic active proteins only as “enzymes”. However, the same techniques also apply to any other substance suitable for the decomposition of organic or inorganic materials, especially to other biocatalytic active molecules and anti-icing molecules, more especially to biocatalytic and/or anti-icing proteins. For example, the molecules could also be ribozymes.
I) Introduction of Enzymes into Deeper Layers of the Surface Coatings:
A method for producing such coating 10 includes the step of providing biocatalytic active molecules 12, 12′ not only on the outermost surface 14 but also within a certain depth below the surface 14, e.g. within a covering layer 24 having a certain thickness so that the corresponding surface 14 remains biocatalytic active even when the outermost layer 16 is eroded. This may include at least one of the following steps:
In the following, several variants to achieve the aforementioned coating 10 are described in more detail with reference to
In
The coatings 10 as shown in
I.a) Immobilizing Proteins in Structures Made of Mesoporous Silicates:
According to one embodiment of the coating 10, the carrier material 27 is mesoporous silicate. In a concrete example, the proteins—e.g. the enzyme molecules 12, 12′—are introduced in structures made of mesoporous silicates and the structures are introduced into the coating material 26 that may be a lacquer 30, for example. The structure may be present as nanoparticle as represented by the particles 28 of
Examples for such mesoporous silicates include for example MCM-41, SBA-15, FDU-5, SBA-16, and FDU-12. The materials may have pore sizes of 2 to 5 nm, 5 to 10 nm, 5 to 8 nm, 1 to 6 nm, or 4 to 9 nm.
For further details of such materials, reference is made to the following literature, incorporated herein by reference:
According to a further embodiment, the carrier material 27 is zeolithe. The proteins—e.g. enzyme molecules 12, 12′—are immobilized on the zeolithe. According to one example, the particles 28 as shown in
For further details of the immobilization to zeolithe, reference is made to the following literature, incorporated herein by reference:
According to another embodiment, the carrier material 27 is porous carbon. Hence, the coating material 26 of
I.d) Immobilizing of Enzymes on Porous Glass:
According to another embodiment, the carrier material 27 is porous glass. Hence, the coating material 26 of
I.e) Coupling of the Enzymes to a Lacquer Matrix:
According to another embodiment, the carrier material 27 used as the coating material 26 of
The enzyme molecules 12, 12′ are coupled directly to the polyurethane matrix of the lacquer. This can be done by simply mixing the lacquer 30 with an enzyme liquid containing the enzyme molecules 12, 12′ before the lacquer 30 is applied to the object surface 20.
I.f) Coupling the Enzymes to Gold Nanoparticles:
According to a further embodiment, the carrier material 27 of the particles 28 as represented in
I.g) Embedding of the Enzymes into Micro Capsules:
Hence, according to this embodiment, the enzymes are embedded in micro capsules 32. The capsules 32 can be made of membranes 34. The micro capsules 32 can be introduced as particles 28 into the coating material 26.
A special variant of this micro capsules 32 is the use of polyvinyl beads or dextran beads. According to this variant, the enzymes are embedded in polyvinyl beads or dextran beads. These beads form the particles 28 that are introduced into the coating material 26.
I.h) Embedding the Enzymes in Fibre Materials:
The fibre materials containing the enzyme molecules can be introduced into other structures.
For example, the fibre materials can be used as fibres in composite materials such as carbon fibres reinforced materials. In a concrete example, fibres to be used for reinforcing a material of the object are soaked in enzyme liquid and then embedded in a plastic matrix.
II) Increasing the Density and/or Activity of the Enzymes:
In the following further embodiments of a method for producing self-regenerating biocatalytic active surfaces and/or coatings are described wherein a step of increasing the density or the activity of the enzymes is employed.
This may be done employing any of to the following steps II.a) to II.c)
II.a) Multi Layer Assembly
All the layers 40, 42, 44 have a similar structure. Thus, self-similar structures are present at the outer surface 14 and are repeated in deeper regions of the coating 10.
According to this embodiment, a multilayer assembly 38 is provided by means of layer by layer deposition. Especially, polyelectrolyte multilayers are provided. For further details, reference is made to the following literature, incorporated herein by reference:
Examples of suitable tree-like structures 48 include the so called dendrimer structures.
For further details, reference is made to the following literature, incorporated herein by reference:
One further possible procedure to increase the density of the biocatalytic active molecules includes immobilizing the enzymes in or on porous aluminium membranes. Such aluminium membranes can be used as carrier material 27 in one of the embodiments as shown in
For further details, reference is made to the following literature, incorporated herein by reference:
A hydrogel (also called Aquagel) is a network of polymer chains that are water-insoluble, sometimes found as a colloidal gel in which water is the dispersion medium. Hydrogels are super absorbent (they can contain over 99% water) natural or synthetic polymers. Hydrogels also possess a degree of flexibility very similar to natural tissue, due to their significant water content.
Hydrogels are, for examples, used in contact lenses (silicone hydrogels, poly-acrylamides).
Common ingredients are e.g. polyvinyl alcohol, sodium polyacrylate, acrylate polymers and copolymers with an abundance of hydrophilic groups.
III) Applying a Liquid Enzyme Cocktail Via Micro Channels or Micro Pores:
The enzymes are not immobilized but are present in a liquid form. When the enzymes are removed from the outer surface 14, for example by erosion, further enzymes are supplied from below. The transport of the enzyme liquid 64 may be conducted similar to a liquid transport in plants. The viscosity and further parameters (for example size of the μ-channels 62) are set in such way that there are no essential losses of molecules due to evaporation.
IV) Producing of Fusion Proteins:
Further embodiments (not shown) include the production of fusion proteins. Especially, the following variants are possible:
The object 22 can be of different kinds. Especially, the object 22 may be an aircraft, for example and aeroplane or a rotorcraft, or a part thereof, for example a wing part.
Further, the self-cleaning and self-regenerating surface structure and/or the coating 10 as presented herein can be used in a rotor 74 of a wind turbine 76, as indicated in
Further, the environment conditions in the vicinity of wind rotors 74 are much easier to handle as, for examples, the environmental conditions in which an aircraft is moved.
The surface structures as presented herein can also be used in all further technical fields where surfaces are to be cleaned and are subject to rough environmental conditions as well as erosion. For example, the object 22 can be a vehicle, a building, a construction, an object to be used in households, for example a furniture, or an industrial product.
| Number | Date | Country | Kind |
|---|---|---|---|
| 09159332 | May 2009 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2010/055748 | 4/28/2010 | WO | 00 | 11/3/2011 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2010/127981 | 11/11/2010 | WO | A |
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| 20060154069 | Lin et al. | Jul 2006 | A1 |
| 20070026193 | Luzinov et al. | Feb 2007 | A1 |
| 20100210745 | McDaniel et al. | Aug 2010 | A1 |
| Number | Date | Country |
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| 10 2006 005614 | Aug 2007 | DE |
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| Stevens, K et al., Nanofibers and nanotechnology in textiles, Woodhead Publishing Limited, 2007, pp. 435-436. |
| International Search Report for PCT/EP2010/055748, mailed Oct. 21, 2010. |
| Written Opinion of the International Searching Authority for PCT/EP2010/055748, mailed Oct. 21, 2010. |
| Partial EP Search Report for EP Application No. 09159332, dated Oct. 23, 2009. |
| Number | Date | Country | |
|---|---|---|---|
| 20120052251 A1 | Mar 2012 | US |
