Adhesive system for rough surfaces

Abstract

The invention relates to a device having a structured coating for adhesion to rough, in particular biological surfaces, comprising a carrier layer (101), wherein a plurality of elevations are provided on the carrier layer (101), which in each case comprise at least one stem having an end face facing away from the surface, and wherein at least on the end face a further layer (104) is arranged, which has a lower modulus of elasticity and is designed as a film connecting the elevations. The film can also be detachable.

Description

Technical Field

[0001] The present invention relates to devices having structured coatings, particularly for adhesion to rough surfaces, especially biological surfaces, such as skin surfaces, such as tympanic membranes. Background Technology

[0002] Adhesion on rough surfaces often presents problems. This is particularly true in the biological field, where many adhesives exhibit insufficient performance. Furthermore, the adhesives often lack compatibility with biological processes such as wound healing.

[0003] An alternative is a dry adhesive surface, such as a gecko structure, which can exhibit adhesion even on rough surfaces without the aid of adhesives.

[0004] Especially on skin surfaces, adhesion (or bonding) is not simple, as these surfaces are both rough and flexible. These surfaces are also typically not flat, but curved. At the same time, the adhesive system should be removable without residue. Therefore, the adhesive system must be flexible and also possess sufficiently strong adhesion.

[0005] Another application area for adhesive systems is tympanic membrane perforation. Tympanic membrane perforation is a frequent problem that can lead to hearing loss or frequent recurring infections. Common causes of tympanic membrane perforation include middle ear inflammation, trauma, and postoperative complications. Essentially, it can be distinguished that there are acute (smaller) perforations (which in most cases close spontaneously) and larger or chronic perforations. These larger perforations require surgical treatment with tympanoplasty or tympanoplasty, which has a high success rate, but in addition to surgical risks, there is a risk of residual perforation. Furthermore, in the case of tympanoplasty, autologous tissue is transplanted, which must be removed separately. One of the main problems in tympanic membrane regeneration is the lack of a backing layer for epithelial cell migration and the formation of the three membranes. As a “support platform,” transplanted tissue or polymers are often used, whose function can then still be improved by using biomolecules. Polymers that can be used include, in particular, gelatin, silk fibroin, chitosan, alginate, or polyglycerol sebacic acid ester. A current review of the results obtained using these polymers and various growth factors can be found in the review article by Hong et al., Int. J. Pediatr. Otorhinolaryngol. 77, 3-12 (2013). Although many of the polymers used produced excellent results in closing perforations, significant differences in tissue morphology were observed.

[0006] Soft Mater 2012,8,8281 by Hamed Shahsavan et al. "Biologically inspired enhancement of pressure-sensitive adhesives using a thin film-terminated The article “interface” in *Macromolecules* by Hamed Shahsavan et al., 2014, 47, 353-364, and *Integrative and Comparative Biology* by Drottlef et al., 2019, 1-9, describes various systems with membrane-capped microstructures. They used pillars with a high elastic modulus of approximately 2.7 MPa (Sylgard 184) for their structures.

[0007] Technical issues

[0008] The object of the present invention is to specify an apparatus having a structured coating that has adhesiveness, particularly on rough and / or biological surfaces, and avoids the disadvantages of the prior art. Summary of the Invention

[0009] The stated objective is achieved by an invention having the features of the independent claims. Advantageous developments of the invention are characterized in the dependent claims. The text of all claims is incorporated herein by reference and becomes part of this specification. The invention also includes all reasonable, and in particular all referenced combinations of the independent and / or dependent claims.

[0010] The objective is achieved by a device having a structured coating, wherein the device includes a carrier layer on which a plurality of protrusions (posts) are provided, each of the protrusions including at least a rod having an end face facing away from the surface, wherein at least one additional layer configured as a film is provided on the end face, wherein the layer includes at least one layer having an elastic modulus lower than that of the corresponding protrusion as a surface.

[0011] The layers configured as a membrane connect the various protrusions. The membrane itself may comprise different layers, with the outermost layer forming the surface of the membrane on the side opposite to the protrusion having a lower elastic modulus than the protrusion. This layer forms contact with the surface to which the device is applied.

[0012] Therefore, in the vertical direction, the device includes at least two regions with different elastic moduli, starting from the carrier layer at the protrusion location; that is, these regions are at least the protrusion and an additional layer disposed thereon. The additional layer and the end face of the protrusion form an interface between the two regions with different elastic moduli. Depending on the manufacturing process, the interface may also include a thin layer for connecting aids.

[0013] Within a given region, the elastic modulus is preferably constant.

[0014] The protrusion itself may also have other regions with different elastic moduli. In this case, the lower elastic modulus of the additional layers is always associated with the protrusion region having the highest elastic modulus.

[0015] The additional layer has a lower elastic modulus than the protrusions on which this layer is disposed. Due to this construction, the outermost layer of the device is particularly soft. As a result, this layer is more flexible and can also better conform to rough and / or soft surfaces.

[0016] Despite being a very soft device overall, it is also able to conform very well to curved surfaces.

[0017] The device according to the invention exhibits particularly good adhesion to surfaces having a roughness depth Rz of at least 30 μm, preferably at least 40 μm, especially when directly compared to a smooth surface having a roughness depth of 0.1 μm. Therefore, the device exhibits particularly good adhesion to surfaces having a roughness depth Rz of up to 100 μm, more particularly up to 80 μm, and very particularly up to 70 μm.

[0018] In another embodiment of the invention, the interface between the additional layer and the end face is parallel to the surface of the additional layer relative to the corresponding protrusion.

[0019] In one embodiment of the invention, the ratio of the minimum vertical thickness of the additional layer above the protrusion to the height of the protrusion is less than 3, preferably less than 1, more particularly less than 0.5, and even more particularly less than 0.3. As a result, the protrusion below the layer has a particularly strong influence on adhesion. The optimal ratio may also depend on the ratio of elastic modulus and the geometry of the interface.

[0020] The elastic modulus, size ratio, and favorable parameters of the interface geometry can be determined through simulation and measurement.

[0021] In a preferred embodiment of the invention, the protrusions on the carrier layer are designed to be columnar. This means that the protrusions are preferably designed perpendicular to the carrier layer and have rods and end faces, wherein the rods and end faces may have any desired cross-section (e.g., circular, elliptical, rectangular, square, rhomboid, hexagonal, pentagonal, etc.).

[0022] The protrusion is preferably designed such that the end face is on the base surface of the protrusion. The vertical projection onto the surface overlaps with the base surface, wherein the overlapping area and its projection onto the end face span (cover) the entire body within the protrusion. In a preferred embodiment of the invention, the overlapping area comprises at least 50% of the base surface, preferably at least 70% of the base surface, and particularly preferably, the overlapping area comprises the entire base surface. Therefore, the protrusion is preferably not inclined, but it may be inclined.

[0023] In a preferred embodiment, the end face is parallel to the base plane and aligned with the surface. If the end face is not parallel to the surface and therefore has a different vertical height, the vertical height of the protrusion is considered to be the average vertical height of the end face.

[0024] In a preferred embodiment of the invention, the protruding rod has a height-to-diameter ratio of 1 to 100, preferably 1 to 10, particularly preferably 1.5 to 5, based on its average diameter.

[0025] In one embodiment, the aspect ratio is greater than 1, preferably at least 1.5, preferably at least 2, preferably 1.5 to 15, and more preferably 2 to 10.

[0026] The average diameter is understood here as the diameter of a circle having the same area as the corresponding cross-section of the bulge, averaged over the entire height of the bulge.

[0027] In another embodiment of the invention, the ratio of the height of the protrusion to the diameter at a specific height is always 1 to 100, preferably 1 to 10, and particularly preferably 1.5 to 5, over the entire height of the protrusion. In one embodiment, the aspect ratio is at least 1, preferably 1 to 3. The diameter is understood herein to refer to the diameter of a circle having the same area as the corresponding cross-section of the protrusion at the specific height.

[0028] The protrusions can have widened end faces, creating a so-called "mushroom" structure. Additional layers can also protrude beyond the end faces, thus forming a "mushroom" structure.

[0029] In a preferred embodiment, the protrusion does not have any widened end face.

[0030] In a preferred embodiment, the vertical height of all the protrusions is in the range of 1 μm to 2 mm, preferably 10 μm to 1 mm, more particularly 10 μm to 500 μm, and preferably in the range of 10 μm to 300 μm.

[0031] In a preferred embodiment, the total vertical thickness of all included layers above the end face, including other layers, is in the range of 1 μm to 1 mm, preferably 1 μm to 500 μm, more particularly 1 μm to 300 μm, preferably in the range of 1 μm to 200 μm, more particularly in the range of 5 μm to 100 μm, and very particularly in the range of 5 μm to 60 μm.

[0032] Based on at least 50% of the projection of the protruding end face onto the surface of the other layer, the other layer preferably has a vertical thickness within one of the above-mentioned or preferred ranges. This thickness is preferably also the average thickness of the entire other layer across the entire device.

[0033] The minimum thickness of the additional layer above the protrusion is preferably always less than the maximum vertical height of the protrusion.

[0034] In a preferred embodiment, the vertical thickness of the carrier layer (backing layer) is in the range of 1 μm to 2 mm, preferably 20 μm to 500 μm, and more particularly 20 μm to 150 μm. In a preferred embodiment, the thickness of the carrier layer is 20 to 60 μm.

[0035] In a preferred embodiment, the base surface corresponds in area to a circle with a diameter of 0.1 μm to 5 mm, preferably 0.1 μm to 2 mm, particularly preferably 1 μm to 500 μm, very preferably 1 μm to 500 μm, and especially preferably 1 μm to 100 μm. In one embodiment, the base surface is a circle with a diameter between 0.3 μm and 2 mm, preferably between 1 μm and 100 μm.

[0036] The average diameter of the rod is preferably between 0.1 μm and 5 mm, more preferably between 0.1 μm and 2 mm, and particularly preferably between 10 μm and 100 μm. The height and average diameter are preferably adjusted according to a preferred aspect ratio.

[0037] In a preferred embodiment, in the case of a widened end face, the surface of the raised end face or the surface of another layer is at least 1.01 times, preferably at least 1.5 times, the area of ​​the raised base face. It can be, for example, 1.01 to 20 times larger.

[0038] In another embodiment, the widened end face is 5% to 100% larger than the base face, particularly preferably 10% and 50% larger than the base face.

[0039] In a preferred embodiment, the distance between the two protrusions is less than 2 mm, more particularly less than 1 mm, and especially less than 500 μm or less than 150 μm. Here, distance is understood to refer to the shortest distance between the two protrusions.

[0040] The protrusions are preferably arranged in a regular, periodic pattern.

[0041] In a preferred embodiment of the invention, the protrusions have a height of 5 to 500 μm, preferably up to 400 μm. The total vertical thickness of the additional layer above the end face is 3 to 100 μm. The average distance between the columnar protrusions is between 5 and 50 μm. The thickness of the carrier layer is between 50 and 200 μm. The diameter is 5 to 100 μm, depending on the distance between the protrusions. The protrusions are preferably arranged in a hexagonal pattern. Very preferably, the density of the protrusions is 10,000 to 1,000,000 protrusions / cm³. 2 .

[0042] The total thickness of the device, including additional layers, protrusions, and carrier layers, is preferably between 50 μm and 500 μm. The thickness of each component is adjusted accordingly.

[0043] In one embodiment of the invention, the total thickness of the device is between 40 and 90 μm. For these thin devices, it is preferred that the protrusions account for at least 30%, and more preferably at least 40%, of the total height of the device.

[0044] The elastic modulus of all regions of the protrusions and other layers is preferably from 40 kPa to 2.5 MPa. The elastic modulus of the softer regions, i.e., especially the elastic modulus of other layers with lower elastic modulus, is preferably from 40 kPa to 800 kPa, more preferably from 50 kPa to 500 kPa, and even more preferably from 50 to 150 kPa. In contrast, regions with high elastic modulus, such as the protrusions and, for example, the carrier layer, preferably have an elastic modulus of 1 MPa to 2.5 MPa, more preferably from 1.2 MPa to 2 MPa. Preferably, for all softer and harder regions, the elastic modulus is within the range specified above (measured using a nanoindenter).

[0045] The ratio of the elastic modulus between the regions of lowest and highest elastic modulus is preferably less than 1:100, more particularly less than 1:80, preferably less than 1:70, independently at least 1:2, and preferably at least 1:3.

[0046] In a preferred embodiment, the elastic modulus of the protrusions and the carrier layer, and, where appropriate, the elastic modulus of the regions of additional layers, is 1 MPa to 2.5 MPa, preferably 1.2 MPa to 2 MPa, while for regions with lower elastic modulus, the elastic modulus is 40 kPa to 800 kPa, preferably 50 kPa to 500 kPa, and particularly preferably 50 to 150 kPa (measured using a nanoindenter).

[0047] Using such a soft material for both the protrusions and the carrier layer allows for the fabrication of relatively thick but relatively flexible devices with adhesive properties similar to those of stiffer structures, yet significantly more flexible. As a result of the membrane bonding, the protrusions are additionally stabilized, preventing the soft protrusions from collapsing. Simultaneously, thicker devices can be fabricated more easily and are easier to manipulate.

[0048] As a result of the stabilization caused by the membrane, the device itself is also stabilized. This is important, for example, when the device must withstand not only adhesive forces but also tensile forces parallel to the contact surfaces. For instance, when applied to a wound to be closed or an eardrum injury. This also allows for a reduction in the elastic modulus of the protrusion and the carrier layer, without in particular sacrificing the stability of the protrusion.

[0049] In another implementation, the ratio specified above describes the ratio of the elastic modulus of the additional layer (soft) and the protrusion (hard).

[0050] Furthermore, this layer is easy to keep clean or sterile because there is virtually no dirt to accumulate in the gaps. This creates a barrier against microbial infection, especially when used on the eardrum. In addition, this "seal" also leads to improved hearing performance in the event of an eardrum perforation.

[0051] Therefore, in this embodiment, the surface of the device appears closed and uniform. Consequently, it can be more easily modified to suit various applications. Thus, surface treatment has no impact on the structuring within the coating.

[0052] Accordingly, the surface can be functionalized or processed using known methods.

[0053] The gaps between the protrusions within the device are preferably left unfilled. Alternatively, the gaps may be filled, wherein the material has a different elastic modulus than that of the protrusions and the carrier layer.

[0054] The protrusions can be composed of many different materials, preferably elastomers, and particularly preferably crosslinkable elastomers. Regions with a higher elastic modulus may also include thermosetting materials.

[0055] The protrusions and additional layers may therefore include the following materials:

[0056] Epoxy and / or silicone-based elastomers, polyurethanes, epoxy resins, acrylate systems, methacrylate systems, polyacrylate homopolymers and copolymers, polymethacrylate homopolymers and copolymers (PMMA, AMMA acrylonitrile / methyl methacrylate), polyurethane (meth)acrylates, silicones, silicone resins, rubbers, such as R rubber (NR natural rubber, IR polyisoprene rubber, BR cis-butadiene rubber, SBR styrene-butadiene rubber, CR chloropropylene rubber, NBR nitrile rubber, M rubber (EPM ethylene-propylene rubber, EPDM ethylene-propylene rubber). Unsaturated polyester resins, formaldehyde resins, vinyl ester resins, polyethylene homopolymers or copolymers, and mixtures and copolymers of the above materials are also preferred. More preferably are elastomers approved by the EU (according to EU Regulation No. 10 / 2011 of 14 January 2011, published on 15 January 2011) or the FDA for use in packaging, pharmaceuticals, and food, or silicone-free UV-cured resins derived from PVD and CVD processes. Here, polyurethane (meth)acrylate represents polyurethane methacrylate, polyurethane acrylate, and mixtures and / or copolymers thereof.

[0057] It can also be a hydrogel, for example based on polyurethane, polyvinylpyrrolidone, polyethylene oxide, poly(2-acrylamido-2-methyl-1-propanesulfonic acid), silicone, polyacrylamide, hydroxylated polymethacrylate, or starch.

[0058] Preferred materials include epoxy-based and / or silicone-based elastomers, polyurethane (meth)acrylates, polyurethanes, silicones, silicone resins (e.g., UV-curable PDMS), polyurethane (meth)acrylates, and rubbers (e.g., EPM, EPDM).

[0059] Particularly preferred are crosslinkable silicones, such as vinyl-terminated silicone polymers.

[0060] Especially for the additional layer in contact with the surface, epoxy-based and / or silicone-based elastomers, polyurethane (meth)acrylates, polyurethanes, silicones, silicone resins (e.g., UV-curable PDMS), polyurethane (meth)acrylates, rubbers (e.g., EPM, EPDM), and more specifically crosslinkable silicones such as vinyl-terminated silicone polymers are preferred.

[0061] The above-mentioned hydrogel or pressure-sensitive adhesive can also be used in other layers.

[0062] In a preferred embodiment of the invention, the additional layer comprises at least one layer with a high elastic modulus (hard), preferably with raised elastic modulus, and a layer thereon with a lower elastic modulus. The underlying layer (support layer) stabilizes the layer (adhesive layer) with the lower elastic modulus. This allows for the use of a particularly soft material for this layer, without it sinking between the raised areas.

[0063] In this embodiment, the thickness of the support layer is between 1 and 100 μm, and the thickness of the adhesive layer is between 5 and 100 μm. Preferably, the thickness of the support layer is between 1 and 50 μm, and the thickness of the adhesive layer is between 10 and 50 μm. Very particularly preferably, the thickness of the support layer is between 1 and 20 μm, and the thickness of the adhesive layer is between 1 and 20 μm.

[0064] In another preferred embodiment of the invention, the additional layer has only a lower elastic modulus (adhesive layer). Thus, although the layer has some settling between the protrusions, its high elasticity makes it highly effective in adapting to rough surfaces.

[0065] In this embodiment, the thickness of the additional layer is between 5 and 100 μm, preferably between 10 and 50 μm.

[0066] In another embodiment, the surface of another layer is treated. The surface properties can be affected in this way. This can be done through physical treatments such as plasma treatment, preferably using Ar / O2 plasma.

[0067] Additives can also form covalent or non-covalent bonds on the surface to achieve, for example, some degree of compatibility with cells. Preferred additives are those used to support cell adhesion, such as poly-L-lysine, poly-L-ornithine, collagen, or fibronectin. These additives are known in the field of cell culture.

[0068] In particular, when used in the medical field, it may be advantageous to store substances in at least a portion of the device and then release them slowly. These substances may be, for example, drugs, such as antibiotics, or adjuvants used to support cell adhesion or cell growth.

[0069] In another embodiment, the protrusions and the carrier layer are made of the same material.

[0070] In another embodiment of the invention, an additional layer having a lower elastic modulus is designed to be separable (removable) from the device; preferably, the entire additional layer of the device is separable. Here, separable means, in particular, that there is no covalent connection between the separable layer and the rest of the device, for example, between the protrusion and the additional layer. The connection is based solely on non-covalent connections.

[0071] In a preferred embodiment of the invention, starting from the end face, the additional layers include a layer with a low elastic modulus for connection to the end face, a support layer, and a layer with a low elastic modulus for adhesion to the surface.

[0072] An inner layer with a lower elastic modulus is used to adhere to the protrusions and is connected solely by adhesive force. As a result, the protruding portion of the device can be detached and reused.

[0073] Due to its contact with surfaces, the outermost layer of this device is easily soiled and therefore cannot be reused after separation, for example, in medical applications. If an additional layer, along with the outermost layer, can be easily replaced, the raised portion of the device can be easily reused by simply applying a new, additional layer. The coated support layer is easier to manufacture than the raised portion of the device.

[0074] In a preferred embodiment of the invention, the additional layer is separable and, starting from the protrusion, has the following structure: an inner adhesive layer, a support layer, and an outer adhesive layer. The inner support layer stabilizes the separable additional layer to prevent tearing during separation. This also allows for better manipulation of the layer. The adhesive layer, bonded to the protrusion, ensures adhesion between the additional layer and the protrusion.

[0075] In this embodiment, the additional layer has a total thickness of 50 to 300 μm, preferably 50 to 150 μm.

[0076] In this case, the thickness of the inner adhesive layer is preferably 5 to 100 μm, more preferably 10 to 50 μm. Independently, the thickness of the support layer is 5 to 100 μm, more preferably 10 to 50 μm. Independently, the thickness of the outer adhesive layer is 10 to 50 μm.

[0077] In a preferred embodiment, the elastic modulus of the support layer is from 1 MPa to 2.5 MPa, preferably from 1.2 MPa to 2 MPa, while the elastic modulus of the adhesive layer is from 40 kPa to 800 kPa, preferably from 50 kPa to 500 kPa, and particularly preferably from 50 to 150 kPa.

[0078] The dimensions of the microstructure correspond to the descriptions of the other embodiments described above.

[0079] For this implementation with additional separable layers, it also allows for the use of microstructures made of relatively rigid materials and similarly achieves improved adhesion.

[0080] In this embodiment, the elastic modulus of the protrusion and the carrier layer is preferably 1 MPa to 4 MPa, more preferably 1 MPa to 3 MPa, particularly preferably 1 MPa to 2.5 MPa, and even more particularly preferably 1.2 MPa to 2 MPa.

[0081] In another embodiment, the device further includes an optional, separable additional layer. Thus, the surface can be protected by a separable foil before use. An additional stabilizing layer may also be disposed on the carrier layer.

[0082] The carrier layer preferably has a thickness lower than the maximum height of the protrusions arranged thereon.

[0083] Since the carrier layer (when it is composed of the same material as the protrusion) includes a material with a high elastic modulus, the thickness of the carrier layer can also affect the elasticity of the entire device.

[0084] The device according to the invention is preferably designed for adhesion on a soft substrate.

[0085] The device according to the invention is specifically designed for adhesion to biological tissue. For this purpose, it may be designed, for example, as a foil. It may also be combined with a device to be fixed (attached). For example, these may be dressing materials, or electrodes or other medical devices, such as implants, more particularly implants that are not permanently anchored to bone, or soft implants. For example, these may be iris implants. Therefore, the invention also relates to implants, for example, those comprising the device according to the invention on at least a portion of the implant's surface.

[0086] The present invention also relates to the use of the above-described device for adhesion to biological tissues. These can be any desired tissue, such as skin or internal tissues, such as organ surfaces, wound surfaces, or tympanic membranes. When applied to the skin, this can be healthy or damaged tissue. The device can be used for fixation of, for example, sensors, dressings, plasters, infusions, etc. However, the device can also be applied to damaged tissues, such as superficial injuries, such as wounds, burns, bruises, chronic wounds, etc. The device allows for the combination of a compatible surface with simultaneous adhesion to biological tissues. Therefore, the device can also be used as a growth substrate for cell culture or for the formation of new tissues. Due to the open internal structure of the device, liquids can also be drained or air can be circulated.

[0087] Treatment of tympanic membrane perforation

[0088] Due to its adhesive properties, the device adheres well to the surface of the tympanic membrane and even allows stress to be applied or exerted. Due to its structure, it also adheres to surrounding tissues, not just the tympanic membrane. Such a device can optionally include different areas with varying adhesive forces. This can be achieved, for example, through the material, the thickness of additional layers, or simply through the distribution of protrusions within the device.

[0089] The device, advantageously designed as a foil, therefore comprises at least a carrier layer with protrusions, and an additional layer is applied to these protrusions. As a result of the foil implementation, the device can be easily trimmed to the desired size. This can even be done by the person performing the treatment (e.g., a doctor).

[0090] Due to its internal structure, the device adheres well to the tissue on which it is applied. This includes not only the tympanic membrane but also surrounding tissue. No liquid components that can flow into the ear are required for application of the device.

[0091] Depending on the materials used, the device can also be transparent, allowing the condition of the tissue beneath it to be studied without disassembly, to determine, for example, the healing process.

[0092] The device can be easily detached again.

[0093] Before use, the device may be subjected to physical or chemical treatment, preferably sterilization. This can be, for example, an autoclaving process, such as sterilization with hot air or steam at 50 to 200°C, more particularly 100 to 150°C, and a pressure of 1 to 5 bar for 5 minutes to 3 hours. During such autoclaving (121°C, 2 bar, 20 minutes), it is impossible to observe any significant change in adhesive stress.

[0094] Other sterilization methods include gamma ray sterilization or ethylene oxide sterilization (ETO).

[0095] In another embodiment, the surface may be treated, for example, with poly-L-lysine, poly-L-ornithine, collagen, fibronectin, gelatin, laminin, keratin, tendinin, or perlecan. Such additives are known in the field of cell culture.

[0096] The present invention also relates to a method for manufacturing an embodiment of the apparatus according to the invention.

[0097] The steps of each method are described in more detail below. These steps need not be performed in the given order, and the method to be outlined may also include additional steps not described.

[0098] Therefore, in the first step, a template is provided for molding multiple protrusions.

[0099] The material for the protrusions is introduced into the template, preferably as a liquid. The material may also optionally have been at least partially cured.

[0100] The material for the carrier layer, i.e., the material for the surfaces on which the protrusions are arranged, is then applied to the template and cured. Particularly preferably, this is the same material used for the rods of the protrusions, so that the carrier layer and the rods are also manufactured in one step, for example, by directly introducing a relatively large amount of material.

[0101] In subsequent steps, the carrier layer and protrusions are separated from the template.

[0102] It may be necessary to inertize the template before filling, for example, by using fluorosilanes.

[0103] In addition, it may be necessary to align the protrusions by mechanical action such as brushing or wiping.

[0104] In addition, materials used for additional layers are distributed on the surface, for example, by spin coating. This layer is then cured. This process can be repeated multiple times using different materials.

[0105] To attach to the protrusions, a curable material is applied and distributed on the top layer, for example, by spin coating. The microstructure with the protrusions is then laid onto the layer such that the end faces contact the layer. The entire device is then cured. As a result, additional layers are firmly attached to the protrusions. The device then detaches from the surface.

[0106] Depending on the materials and structure, plasma treatment may be required between the application of various materials, preferably oxygen plasma or air plasma. This allows for minimizing the influence of different layers during the curing process. Adhesion is also improved.

[0107] Plasma treatment of the end faces of the microstructures may also be necessary before installation. For example, when the contact area of ​​the microstructures is particularly small.

[0108] Problems may occur during the separation process, especially when the first layer applied is very soft.

[0109] In another embodiment, a layer of material having a different solubility than the material of the curing device is applied to the substrate so that it can be selectively dissolved.

[0110] Then—as described above—an additional layer and microstructure are applied to the auxiliary layer. Thereafter, the auxiliary layer is selectively dissolved, thereby separating the resulting device from the substrate. The material of the auxiliary layer is preferably water-soluble, for example, by treatment in ultrasound. A preferred material for the auxiliary layer is a water-soluble polymer, such as polyvinyl acetate.

[0111] Therefore, in this method, an auxiliary layer is first applied to the substrate and optionally cured. Then, the topmost material (adhesive layer) for the device is applied to this layer and cured. Afterward, depending on the nature of the device being manufactured, additional layers are applied. These can be additional soft layers or support layers. These layers can be cured in their respective cases. Microstructures are then applied. As mentioned above, it may be necessary to pre-apply an uncured layer that only cures after the microstructures are applied. The auxiliary layer is then selectively dissolved and the device is separated. Surface cleaning may also be required to remove any residue from the auxiliary layer.

[0112] In one embodiment of the invention, instead of an auxiliary layer, a material that is particularly easy to separate is used as the base of the first layer. In this case, a material having a coating made of fluorinated silicone or fluorinated silane is preferred, such as a release liner. It can be, for example, a foil with a corresponding coating.

[0113] The release liner should have the smoothest possible surface, as any unevenness will be molded onto the top layer.

[0114] Further details and features are derived from the following description of preferred exemplary embodiments in conjunction with the dependent claims. Here, each feature may be implemented individually or as a combination of multiple features. The possibilities for achieving the objective are not limited to the exemplary embodiments. For example, the range description always includes all—unmentioned—intermediate values ​​and all possible sub-ranges.

[0115] Exemplary embodiments are schematically illustrated in the accompanying drawings. The same reference numerals in the various figures denote the same or functionally identical elements or elements that correspond to each other in function. Specifically:

[0116] Figure 1 An overview of the manufacturing method of the adhesion structure of the film end cap;

[0117] Figure 2 Displays (A) a top view overview of sample A at low magnification, with bottom arrows indicating upright columns and orange arrows indicating several collapsed columns; (B) a top view overview of sample A at higher magnification, showing collapsed columns up close (top arrows); (C) a cross-sectional overview of sample A at high magnification, showing the resolved layers of the substrate used only for fixation (adhesive layer and glass substrate); and (D) a schematic diagram of sample A, where MDX-4 is marked in gray with magnitude indication, and all length data are in μm. For A, the scale is 500 μm, and for B and C, the scale is 100 μm.

[0118] Figure 3Display: (A) Top view overview of sample B at low magnification, with arrows pointing to the voids caused by the collapsed column; (B) Top view overview of sample B at higher magnification, with arrows pointing to surface irregularities and dirt; (C) Cross-sectional overview of sample B at high magnification; (D) Schematic diagram of sample B, where MDX-4 is marked in gray with magnitude indication, and all length data are in μm. For A, the scale is 500 μm, and for B and C, the scale is 100 μm.

[0119] Figure 4 SEM micrographs of the samples: A) Sample A: Image only of the microstructured portion (A). B) Sample B, where an end membrane composed of the same material as the microstructured portion has been used as a support layer (B). * Points to the end layer. C) Sample C after the application of a soft skin adhesive layer (C). * Points to the boundary layer between the two layers. D) Allows viewing of the underside of the end layer (D);

[0120] Figure 5 Showing the cross-section of sample C;

[0121] Figure 6 Cross-sections of different B samples are shown: the thickness of the termination layer can be adjusted in a defined manner via spin coating. A spin coating speed of 800 rpm (A) results in a layer thickness of 60.5 μm, 2000 rpm (B) = 31.3 μm, and 9000 rpm (C) = 12.2 μm. The layer thickness can be further reduced by adding solvent to the polymer;

[0122] Figure 7 Showing various microstructured samples and flat reference samples with considerable thickness and structure; A) a sample with a backing layer and microstructure, or A reference sample; B) a sample with a backing layer, microstructure and support layer, or B reference sample with a substrate and support layer; C) a sample with a backing layer, microstructure, support layer and “adhesive layer”, or C reference sample with a substrate, support layer and “adhesive layer”, from bottom to top in their respective cases.

[0123] Figure 8 Showing from Figure 7 The stress and separation energy (work) of the samples in Table 1 (holding time 1 second);

[0124] Figure 9 Displaying rheological measurements of different samples;

[0125] Figure 10 This demonstrates the fabrication of a membrane end cap post without a support layer;

[0126] Figure 11 A schematic diagram showing an adhesion system using a separable membrane;

[0127] Figure 12 An exemplary embodiment of an adhesion system having a separable membrane is shown;

[0128] Figure 13 A schematic diagram showing the peel measurement is displayed;

[0129] Figure 14 This illustrates an implementation of a method for manufacturing an adhesive system.

[0130] Figure 15 This shows a schematic diagram of the measuring device used to determine the adhesion force value.

[0131] Figure 16 Exemplary illustrations showing stress-time curves (left) and stress-stroke curves;

[0132] Figure 17 Photographs showing the microstructure after removal from the mold (A) and after mechanical processing (B).

[0133] Figure 18 An optical micrograph showing one embodiment of the present invention;

[0134] Figure 19 Displays peeling measurements at different removal speeds;

[0135] Figure 20 This shows the measurement of the vibration characteristics of the mouse tympanic membrane.

[0136] Figure 1 An overview of the fabrication method for the adhesive structure of the membrane end cap is shown. The completed adhesive system consists of a microstructured component (101) made from Silastic MDX4-4210 and an end membrane, which is composed of a combination of MDX4-4210 layers (102, 103, step III.ai) and an end layer made of MG7-1010 (104, VI.ai) subsequently applied for skin adhesion. The end layer can also be fabricated without the MDX4 support layer, as shown in III bi. The individual steps are described below. The material and thickness of the corresponding layers or structures can be varied by changing the materials or application conditions.

[0137] I. Wafer Molding

[0138] The wafer (silicon wafer) was placed in a petri dish and filled with a material for the microstructure mold (PDMS, Elastosil 4601, Wacker, Riemerling, Deutschland, 100). After degassing, a glass plate (111) was placed on top and cured at 75°C for at least 3 hours. The cured mold (100) was then removed. The wafer now possesses the subsequent microstructure.

[0139] The mold was silanized under reduced pressure (20 mbar) using fluorosilane (tridecylfluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane, 50 μL solution.

[0140] II. Fabrication of the microstructured components of the adhesion system

[0141] For the microstructure material, the two components (Silastic MDX4-4210) are weighed and mixed in a ratio of A:B (10:1). This material is used for all structures and layers made of Silastic MDX4-4210.

[0142] The mold (100) is placed on a glass plate (111) and filled with a material for microstructures. Spin coating is performed (3000 rpm, 120 seconds) to smooth the surface. This yields a filled mold with a small overlay. Degassing may be necessary before spin coating.

[0143] Simultaneously, a material (Silastic MDX4-4210) for the backing layer is applied to a plasma-activated glass plate. A layer of defined thickness is then produced by spin coating (9000 rpm, 120 seconds). This plasma-activated glass plate is then applied to the filled microstructure. The structure is rotated 180° and placed on the plasma-activated glass plate (112, oxygen-argon plasma, 2 minutes) and cured (95°C, 1 hour). This attaches the microstructure to the backing layer. The oxygen-argon plasma effectively bonds the structure to the glass plate, allowing for efficient separation of the cured microstructure from the mold.

[0144] The structure is applied to a new glass plate (111). Mechanical action, such as brushing or combing, may be needed to align the columns of the microstructure. Figure 17 Sample A was obtained, i.e., the microstructure without the end capping membrane. Its thickness and material can be easily adjusted by separately fabricating the backing layer.

[0145] Figure 2 Micrographs (A, B, C) and schematic diagrams of sample A are shown. The microstructures were also used in other experiments.

[0146] As a reference sample, a film made of the same material and with a similar thickness was produced by a doctor blade.

[0147] III. Fabrication of the AI ​​Support Layer

[0148] The outer layer material (Silastic MDX4-4210, 103) was applied to a glass plate (111) and distributed by spin coating (9000 rpm, 180 seconds). The coating was cured at 95°C for 1 hour. Subsequently, the support layer material (Silastic MDX4-4210, 102) was applied and distributed by spin coating (9000 rpm, 180 seconds). Then, the fabricated microstructure (101) with pillars was placed on the uncured applied layer, ensuring the pillars were in contact with at least the last applied layer. The entire structure was then cured at 95°C for 1 hour. The resulting structure (sample B) was rotated 180° and a backing layer was applied to the glass plate.

[0149] Figure 3 This shows a photomicrograph of sample B.

[0150] For the reference sample, for example, the material (Silastic MDX4-4210) of the reference structure is applied to a glass plate using a doctor blade. The thickness is similar to that of the microstructure. A base layer of material (Silastic MDX4-4210) is applied onto this layer and distributed by spin coating (9000 rpm, 180 seconds), and the entire layer is cured at 95°C for 1 hour. A second layer of material (Silastic MDX4-4210) is then applied onto this layer, distributed by spin coating (9000 rpm, 180 seconds), and cured at 95°C for 1 hour.

[0151] III. Manufacturing of the unsupported end membrane

[0152] The manufacturing process is schematically shown in Figure 10The auxiliary layer material (120, 20% PVA polyvinyl acetate in H2O) was applied to a glass plate (111) and distributed by spin coating (3000 rpm, 60 s), then cured at 95°C for 10 minutes. The adhesive layer material (106, Dow Corning MG7-1010) was then applied on top, distributed by spin coating (4000 rpm, 120 s, 100 rpm / s), and cured at 95°C for 1 hour. Subsequently, the material for another adhesive layer (105, Dow Corning MG7-1010) was applied and distributed by spin coating (9000 rpm, 180 s). The fabricated microstructure (101), along with the pillar, was then placed on the uncured applied layer (105), ensuring the pillar was at least in contact with the layer. The entire structure was then cured at 95°C for 1 hour. The sample was then cut to size if necessary. Subsequently, the auxiliary layer (120) was selectively dissolved in water (ultrasonic bath for 10-20 minutes). The separated composite structure, along with the backing layer, was applied to a glass plate and dried. B-OS samples were obtained. The average thickness of the adhesive layer was 27 μm. B-OS samples with a thickness of 70 μm were also fabricated.

[0153] For the reference sample, for example, the material of the reference structure (Silastic MDX4-4210) was applied to a glass plate using a doctor blade. The thickness was similar to that of the microstructure. The base layer material (Dow Corning MG7-1010) was then applied onto this layer and distributed by spin coating (1000 rpm, 120 seconds), and the entire layer was cured at 95°C for 1 hour. The material for the second layer (Dow Corning MG7-1010) was then applied onto this layer and distributed by spin coating (9000 rpm, 180 seconds), and cured at 95°C for 1 hour.

[0154] If the microstructure is capped with a membrane, the method of using an auxiliary layer can also be used to fabricate C samples.

[0155] IV ai final adhesive layer manufacturing

[0156] For the viscoelastic layer, a mixture of viscoelastic material MG7-1010 (Dow Corning, Midland, USA) was prepared. The two-component system was weighed and mixed in a 1:1 ratio.

[0157] The material for the adhesive layer (104, Dow Corning MG7-1010) was applied to the structure from III.ai by spin coating (4000 rpm, 120 seconds) and cured at 95°C for 1 hour. Sample C was obtained.

[0158] Figure 4 , 5Figures 6 and 7 show photographs of different samples. Measurements were performed using sample C with the following values: backing layer: 71.99 + / - 25.16 μm, microstructure height: 208.44 + / - 18.87 μm, support layer thickness (102, 103): 19.7 + / - 4.94 μm, adhesive layer: 21.25 + / - 12.05 μm.

[0159] Table 1 and Figure 8 The results of adhesion tests on a substrate simulating skin roughness are shown for each sample. Figure 7 Adhesion stress and work: The adhesion stress and separation work of samples with different microstructures were measured compared with unstructured samples with similar layered structures. Clearly, the microstructured samples not only exhibited higher adhesion stress but also higher work on rough substrates.

[0160] Table 4 shows that the measured sample pairs have different roughness (R). z The adhesive stress (holding time 1 second) of the substrate (value) is expressed in kPa. Table 3 shows the same data, where the values ​​for smooth substrates are all set to 100% in their respective cases. Clearly, the samples with adhesive layers (C, BoS) lose significantly less adhesion in the case of rough substrates. The samples were manufactured with auxiliary layers or release liner, and therefore have better adhesion values ​​than the samples in Table 1 because the adhesive layer surface has better flatness in these cases.

[0161] Figure 11 This illustrates an adhesion system with separable end membranes. The system consists of two components, an end membrane (I) and a microstructured portion (II, 101), which are manufactured separately and joined together by pressing in step 1. The layer structure of the three-layer end membrane is as follows: an adhesive layer (131, Dow Corning MG7-1010), an elastic support layer (132, SilasticMDX4-4210), and an adhesive layer (132, Dow Corning MG7-1010). In the second step, the adhesion system can be used and applied to a rough surface (134, e.g., skin). During application, the bottom layer 132 becomes soiled. Because the connection between the microstructure 101 and the inner adhesive layer 131 is reversible, the microstructure and the membrane can be separated. In this case, the end membrane is discarded, and the microstructured component can be reintroduced into the product lifecycle. The end membrane can also be applied to a microstructure on which a support layer has already been applied. In this method, costly and complexly manufactured microstructures can be reused.

[0162] Figure 12An exemplary embodiment of an adhesion system with a separable membrane is shown. The membrane is manufactured by spin-coating various materials three times. The end membrane (A) consists of adhesive layers (131, 132) and a support layer (130). (B) An optical micrograph of a cross-section of the membrane is shown. The two adhesive layers (MG7-1010) appear darker, while the middle support layer (MDX4-4210) appears lighter. Its thickness is 32.32 μm. The membrane itself is applied to glass. The membrane is applied to different structures (C, microstructures made of Sylgard 184, Tesafilm, Sylgard 184 membrane with microstructure thickness) and used for peel measurements (D, see...). Figure 13 (180°, 1 mm / step, the maximum force measured is divided by the width of the sample). Clearly, this system achieves the advantages of the system according to the invention, while the membrane remains separable.

[0163] Figure 18 An optical micrograph showing a separable membrane (top) on a microstructure.

[0164] Figure 19 The maximum forces measured for different support systems applied to the membrane are shown. The pillars are microstructures made of Sylgard 184 (protrusion height: 187±1.5 μm, support layer 62±4 μm), the tape is Tesafilm (thickness 59±1.3 μm); the Sylgard 184 is a membrane made of Sylgard 184 (thickness 295±8.4 μm).

[0165] In measurements at a removal rate of 0.5 mm / step (top), measurements were performed using a membrane with the following structure: MG7-1010: 30 ± 4.5 μm / MDX4-4210: 25 ± 5 μm / MG7-1010: 33 ± 7 μm. Measurements were performed three times.

[0166] In measurements at a removal rate of 1 mm / step (below), measurements were performed using a membrane with the following structure: MG7-1010: 28 ± 3.5 μm / MDX4-4210: 22 ± 4.5 μm / MG7-1010: 27 ± 4 μm. Measurements were performed three times.

[0167] Figure 13A schematic diagram of the peel measurement is shown. A carrier 143 is applied to a hexapod 144. A substrate 142 is applied to a vertical region. A substrate with elasticity similar to skin is used. Furthermore, a model of artificial skin (ex vivo skin) was created to obtain a replica of human skin. The substrate to be tested is mounted on a strip 141 connected to a load sensor 140, which can be pulled parallel to the surface while measuring the force. The following measurement parameters were used: holding time: 60 seconds; removal direction 180°; removal speed 1 mm / step; preload: 1.1 kPa (area 0.75 × 0.75 cm). Different substrates were measured. The measurements shown in the figure were performed using an ex vivo skin (Vitroskin) impression (Turboflex). a =4.43μm, R z =25.3μm). The strip width is 6.5-7mm. The measurement length depends on the substrate and should not exceed 7mm.

[0168] Figure 14 Another embodiment of the method for manufacturing the adhesive system is shown. Here, the adhesive layer 132, which will later become the outermost layer, is applied to the release liner (fluorinated, 135, step I, 3M Scotchpak 9709 release liner, a fluorosiloxane-coated polyester film). Based on this, additional layers, such as adhesive layers, support layers, can then be applied according to the desired embodiment until the microstructure is applied to these layers. These layers can be manufactured by spin coating and curing as described previously. For the application of the microstructure 101, the last applied layer with the applied microstructure is cured, or the last applied layer is an adhesive layer. Figure 14 The application of support layer 130 as step II is shown. Adhesive layer 131 is applied to this layer (step III). Microstructure 101 is applied to adhesive layer 131 (step IV). Alternatively, in Ia, microstructure 101 is applied directly or after the application of additional adhesive layers (105, 106). For different materials, it may be necessary to treat the surface with air plasma before applying the next material. This prevents particularly soft layers from altering their properties due to successive curing steps.

[0169] Thanks to the peeling liner 135, the adhesive system can be easily and without damage separated. Furthermore, manufacturing time and system quality are reduced.

[0170] If placing microstructures with end caps, sample B can also be fabricated using a method that utilizes a peel-off liner. Alternatively, one or more MDX4-4210 layers are applied as a final layer and then attached to the microstructure as described above. For better adhesion of the MDX4-4210 layers, a plasma treatment (air plasma) may be necessary prior to application to improve adhesion.

[0171] By using a release liner, a more uniform sample surface is achieved, resulting in further improvements in adhesion. With a holding time of one second, the BoS sample (with the same microstructure and an adhesive layer thickness of 30 μm) delivered 641 ± 79 mJ / m². 2 The separation work and stress were 14.84 ± 1.18 kPa, while the reference model only showed 79.03 ± 39.91 mJ / m. 2 The separation work was 7.25 ± 3.04 kPa. With increased holding time, the separation work of the BOS sample more than doubled, specifically by 56%. Adhesion stress showed an increase of 35%. For the BoS-reference sample, a 61% increase in separation work and a 33% increase in adhesion stress were measured.

[0172] Rheological data were measured using a rheometer (MCR 300, previously Physica, Graz, Austria, Anton Paar). The rheometer has a conical-plate geometry. Small quantities of polymer mixtures were prepared in their respective conditions before measurements could be performed. Mixtures of MG7-1010, MDX4-4210, and Sylgard 184 at a ratio of 10:1 and Sylgard 184 at a ratio of 100:1.6 were tested. The latter two mixtures were used as control mixtures in the literature for microstructure analysis. Each sample was measured three times, and each measurement was freshly prepared.

[0173] Figure 9 The graphical evaluation of the rheological measurements is shown (A: storage modulus (G'), B: complex modulus (G*), C: loss modulus (G”), D: damping factor (tan δ = G” / G')).

[0174] The elastic modulus of each material can be estimated using the storage modulus. These values ​​differ from those measured using a nanoindenter, but they do provide relative proportions.

[0175] Under the assumption of E ~ 3*G', the values ​​reported in Table 2 are obtained for 1 Hz. These values ​​also indicate that Sylgard 184 10:1 is significantly harder than MDX4-4210. This corresponds to values ​​of 2.7 MPa and 1.9 MPa, respectively, measured using a nanoindenter (for a steel hemisphere, sample thickness > 1 mm, and indentation depth of 5000 nm in the sample).

[0176] Figure 15This diagram shows a schematic structure of a measuring apparatus used to determine adhesion values. In the figure, 's' describes the position of the platform in the z-direction. The platform moves along the positive z-direction to bring the sample into contact with the substrate. Once a specified compressive prestress is reached, this position is maintained for a specified holding time. Measurement variables, such as induced force, are detected by a weighing sensor and can be read from the screen. The sample is secured to an adhesive substrate on a glass slide, which is fixed to the platform by a screw mechanism of a sample holder. To change the sample position, the platform, along with the sample, can also be moved in the x and y directions. The position and contact of the sample can be observed and adjusted using optical elements such as prisms and cameras 1 and 2.

[0177] The platform moves toward the substrate at a speed of 30 μm / s along the positive z-direction until a compressive prestress of 70 ± 20 mN (or 10 ± 4 kPa) is established. After a specified holding time of one or thirty seconds in contact with the substrate, the sample is separated from the substrate. For this purpose, the platform moves along the negative z-direction at a removal speed of 10 μm / s. The measuring device includes a load cell (maximum 3 N, Tedea-Huntleigh 1004, Vishay Precision Group, Basingstoke, GB) designed to record low separation forces. The system records data relative to time t and platform position s. z The induced normal force F in the z-direction. A prism is integrated into the sample holder for optical detection of the sample position, enabling observation of the contact between the sample and the substrate. The use of two cameras (Camera 1 and 2) (DMK23UX236, The Imaging Source, Germany) allows for tracking and recording measurements on a computer screen. A goniometer is used to adjust the contact area between the sample and the test substrate.

[0178] Figure 16 Exemplary diagrams showing stress-time and stress-stroke curves are displayed. The corresponding maximum values ​​of the curves represent the selected compressive prestress, i.e., the stress at which the sample is pressed against the test substrate. In their respective cases, the minimum values ​​of the curves correspond to the adhesive stress (σ). s The region encompassed by the curve and zero line in the stress-stroke diagram corresponds to the separation work (W) that must be applied to separate the sample from the substrate. deb The area of ​​each test substrate was determined using an optical microscope. At time t0 (when the separation operation begins, but the sample and substrate are still in complete contact, and the compressive prestress has crossed zero), the position s of the platform was determined. z Called s0 ( Figure 16 Time point t end Defined as the end of the detach operation (s) end At the point in time ( ), the adhesion stress is equal to 0.

[0179] The test substrate used was as follows: a smooth glass (polished glass) model in epoxy resin (EGS area 6.2 mm²). 2 R a =0.01μm, R z =0.10μm), a rough glass (etched matte glass) model in epoxy resin (EGR, area 6.95mm²) 2 R a =0.22μm, R z =1.97μm) and an in vitro skin model made of epoxy resin (area 7.26mm). 2 R a =9.48μm, R z =49.66 μm). A mouse tympanic membrane model was also used. For these models, R can be determined. z =2.2μm (Pars Tensa) and R z = 13 μm (Pars Flaccida) roughness depth. All R a and R z All values ​​were measured using a profilometer (SURFCOM 1500SD3, Carl Zeiss, Oberkochen, Germany). a and R z Determined according to DIN EN ISO standard 4287:2010-07.

[0180] The curvature of the Pars Tensa tympanic membrane is 35.33 ± 3.5° (measured by optical microscopy). However, in applications on the tympanic membrane, excessive adhesion during separation can also have adverse effects due to the membrane's high sensitivity. In the case of the device according to the invention, adhesion can be easily adjusted by changing parameters.

[0181] Figure 20 Vibrational characteristics of mouse tympanic membranes (intact, perforated, perforated with a simple membrane, perforated with a microstructure).

[0182] Distorted otoacoustic emissions (DPOAEs) were measured in anesthetized female mice aged 6–8 weeks. The race was CBA / J. The frequency range studied was 8 kHz to 17.9 kHz. A flat membrane with a diameter of approximately 1 mm and a microstructured system were used. The diameter of the perforations was between 0.5 and 0.9 mm.

[0183] The microstructure used has a 20 μm adhesive layer without a support layer, 40 μm diameter protrusions with a height of 20 μm, and a 20-50 μm backing layer. The minimum distance between the pillars is 20 μm. They are arranged regularly in a hexagonal pattern.

[0184] The results show that the membrane according to the invention has no negative effects. For the same weight, the volume of the microstructure according to the invention is slightly larger than that of the unstructured membrane. The microstructure is inherently significantly more stable and can be applied more precisely.

[0185] Table 1

[0186]

[0187] Table 2

[0188] Energy storage modulus G' [Pa] E~3*G'[MPa] G'Sylgard 184 10:1 41 4000 1.24 G'MDX4-4210 360 666 1.08 G'MG7-1010 27 600 0.0828 G'Sylgard 100:1.6 7673 0.023

[0189] Table 3

[0190] <![CDATA[R z [μm]]]> 0.10 1.97 49.66 A 100 80.7 2.50 A-Reference 100.00 56.2 0.00 B 100 66.5 5.23 B-Reference 100.00 62.9 0.00 C 100 79.9 32.70 C-Reference 100.00 67.4 4.80 B-OS (30μm) 100 85.9 51.20 B-OS reference (30μm) 100.00 65.3 7.70 B-OS (70μm) 100 83.77 51.30 B-OS reference (70μm) 100.00 67.2 12.20

[0191] Table 4

[0192]

[0193]

[0194] Figure Labels

[0195] 100 Microstructure Mold (Elastosil 4601)

[0196] 101 Microstructure (Silastic MDX4-4210)

[0197] 102 Support Layer (Silastic MDX4-4210)

[0198] 103 layers (Silastic MDX4-4210)

[0199] 104 Adhesive Layer (Dow Corning MG7-1010)

[0200] 105 Adhesive Layer (Dow Corning MG7-1010)

[0201] 106 Adhesive Layer (Dow Corning MG7-1010)

[0202] 110 chips

[0203] 111 Glass Plate

[0204] 112 Plasma-activated glass plate

[0205] 120 auxiliary layer r

[0206] 130 Support Layer

[0207] 131 Adhesive layer

[0208] 132 Adhesive layer

[0209] 133 Pollution

[0210] 134. Rough surface (skin)

[0211] 135 Peeling gasket

[0212] 140 Load Cell (Kraftmessdose)

[0213] 141 strips

[0214] 142 base

[0215] 143. Carrier (glass)

[0216] 144 Hexapod

Claims

1. Device with a structured coating for adhering to a rough surface, wherein the device comprises a carrier layer, wherein a plurality of protrusions is arranged on the carrier layer, which protrusions comprise in each case at least one stem with an end face facing away from the surface, characterized in that On the end face at least one further layer designed as a film is arranged, wherein the further layer comprises at least one layer with a lower modulus of elasticity than the layer of the respective protrusion, i.e. at least one layer with a low modulus of elasticity, and, starting from the end face, the further layer comprises a layer with a low modulus of elasticity for the connection to the end face, a support layer and a layer with a low modulus of elasticity for the adhesion to the rough surface, wherein the modulus of elasticity of the layer with a low modulus of elasticity is between 40 kPa and 800 kPa.

2. The apparatus of claim 1, wherein, The protrusions have an aspect ratio of more than 1.

3. The apparatus of claim 1, wherein, The protrusions have an aspect ratio of at least 1.

5.

4. The apparatus of claim 1, wherein, The modulus of elasticity of the protrusions and of the carrier layer is between 1 MPa and 2.5 MPa.

5. The apparatus of claim 1, wherein, The further layer with a low modulus of elasticity is detachable from the device.

6. The apparatus of claim 1, wherein, The device is designed for adhesion on soft substrates.

7. The apparatus of claim 1, wherein, The device is designed for adhesion on biological tissue.

8. The device according to claim 7 for use in the treatment of a tympanic membrane perforation.

9. Implant comprising a device according to one of claims 1 to 8.

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