Abstract: A microstructured filter having an inlet for unfiltered fluid; an outlet for filtered fluid; a plurality of projections which are arranged in at least two rows in mutually juxtaposed relationship, project out of a base plate and are an integral component of the base plate; a plurality of passages between the projections and a cover plate which is securable to the base plate to cover the projections and the passages. The passages form a plurality of through paths from the inlet to the outlet. The inlet includes an elongate inlet slot for the unfiltered fluid that extends over approximately the entire filter width and is approximately as high as the projection on the outlet side of the filter.

Abstract: A method comprises depositing an organic material on a substrate; depositing additional material different from the organic material after depositing the organic material; and removing the organic material with a compressed fluid. Also disclosed is a method comprising: providing an organic layer on a substrate; after providing the organic layer, providing one or more layers of a material different than the organic material of the organic layer; removing the organic layer with a compressed fluid; and providing an anti-stiction agent with a compressed fluid to material remaining after removal of the organic layer.

Abstract: A method for manufacturing a liquid jet recording head having an element substrate provided with a plurality of discharge energy generating elements for applying discharging energy to a recording liquid in accordance with image data, a liquid chamber for storing the recording liquid, and a top plate having a plurality of nozzles, is provided. The method includes a step of forming, on an anisotropic-etching mask layer provided on a nozzle surface of the top plate, compensation patterns extending to a liquid chamber region in order to form the nozzles and the liquid chamber by anisotropic etching, and a step of performing anisotropic etching of the top plate through the mask layer and forming the liquid chamber to have a substantially rectangular shape at the nozzle surface of the top plate by over-etching portions with the compensation patterns.

Abstract: An ink jet recording head is capable of: preventing any of stagnation in ink flow, formation of vapor bubbles, cavitation, or like problems from occurring in the ink flow; realizing an excellent ink ejection operation, and thereby realizing a high quality gradation expression in recording; and, lessening a degree of a required accuracy both in dimension and in alignment of its components being stacked together. In a method for manufacturing the ink jet recording head provided with a pressure generating chamber, this chamber is constructed of a through-hole of a chamber plate and a pair of plates, between which plates the chamber plate is sandwiched.

Abstract: The present invention discloses a method and apparatus for the directed formation of a re-entrant micro-jet formed upon the collapse of a working cavitation bubble formed proximate to a work surface. A target bubble, formed between the work surface and the working cavitation bubble, is utilized to direct the re-entrant micro-jet to the work surface.

Abstract: The invention relates to a sheet material having metal points (8) and surfaces (2 and 3) located opposite one another, wherein the sheet material (1) has through-holes (4) from one surface (2) to the surface (3) located opposite. Those through-holes (4) are filled with needle-point-shaped conical pins (5) or through-contacts (6) of electrically conducting material, whereas the surrounding sheet material in a preferred embodiment of the invention consists of an insulating plastics material (7). In a further embodiment of the invention, instead of the insulating plastics material (7) there are provided needle-shaped pins that are surrounded by air or some other gaseous medium. The invention further relates to a method for the production of such a sheet material (1) and to forms of use of the sheet material (1).

Abstract: The present invention provides a shadow mask having an improved resistance to an impact such as vibration or dropping so as to keep a constant quality of a color cathode-ray tube.

Abstract: The present invention provides methods for manufacturing microstructured optical fibers having an arbitrary core size and shape. According to one embodiment of the invention, a method of fabricating a photonic band gap fiber includes the steps of forming an assembly of stacked elongate elements, the assembly including a first set of elongate elements, the first set of elongate elements defining and surrounding a core volume, and a second set of elongate elements surrounding the first set of elongate elements, wherein the core volume defined by the first set of elongate elements has a shape that is not essentially an integer multiple of the external shape of the elongate elements of the second set of elongate elements; including the assembly in a photonic band gap fiber preform; and drawing the photonic band gap fiber preform into the photonic band gap fiber.

Abstract: A method for forming a sensor including the steps of providing a base wafer and forming a sensor cavity in the base wafer. The method further includes the step of coupling a diaphragm wafer to the base wafer, the diaphragm wafer including a diaphragm portion and a sacrificial portion. The diaphragm wafer is coupled to the base wafer such the diaphragm portion generally covers the sensor cavity. The method further includes the steps of reducing the thickness of the diaphragm wafer by removing the sacrificial portion, and forming or locating at least one piezo resistive portion on the diaphragm portion.

Abstract: A method for treating a film of material, which can be defined on a substrate, e.g., silicon. The method includes providing a substrate comprising a cleaved surface, which had a porous silicon layer thereon. The substrate may have a distribution of hydrogen bearing particles defined from the cleaved surface to a region underlying said cleaved surface. The method also includes increasing a temperature of the cleaved surface to greater than about 1,000 Degrees Celsius while maintaining the cleaved surface in a etchant bearing environment to reduce a surface roughness value by about fifty percent and greater. Preferably, the value can be reduced by about eighty or ninety percent and greater, depending upon the embodiment.

Abstract: In a method for manufacturing an ink jet recording head provided with a pressure generating chamber, this chamber includes a through-hole of a chamber plate and a pair of plates, between which plates the chamber plate is sandwiched. The processing step for forming this through-hole further includes the sub-steps of forming a first resist film and a second resist film on a first and a second surface of the chamber plate, respectively, wherein the resist films assume substantially a same shape, but are different in length from each other when measured in a direction parallel to a flow direction of ink, and etching away both the first and second surface of the chamber plate using the resist films as its masks so that the through-hole is formed in the chamber plate and serves as the pressure generating chamber.

Abstract: A particle filter for microelectromechanical systems is provided that includes a particle trap formed on a substrate material. The particle trap includes an array of multidimensional geometric structures in an adjacent relationship. The geometric structures further define a plurality of multidimensional voids therebetween for trapping particles therein. The individual multidimensional geometric structures are formed by a plurality of vertically interconnected geometric shapes to define different configurations of voids between the adjacent geometric structures. In one embodiment of the filter system, an electrical bias is applied to the array of multidimensional geometric structures to facilitate attracting and trapping of particles in the filter.

Abstract: The invention provides microfabricated silicon substrates and devices having extremely small apertures (termed “nanoapertures”) and methods for producing such nanoapertures. The devices have a nanoaperture (which may have a diameter ranging from about a few millimeters to as small as a few nm) across a substrate effective to connect two regions separated by the substrate. The devices are suitable for the formation of lipid bilayer membranes across the apertures, and for use in devices such as biosensors. Substrates and devices may include multiple nanoapertures, which may each support a lipid bilayer membrane, allowing fault tolerant devices such as fault-tolerant biosensors, and allowing devices able to sense more than one target molecule.

Abstract: The ceramic member of this invention is formed on the surfaces of crystal grains with a plurality of protrusions having smaller diameter than that of the crystal grain, said crystal grain composing at least the surface or its vicinity of a dense ceramic base material of purity being 95 wt % or higher. Such ceramic members may be produced by performing the surface of a dense ceramic base material with a corrosion treatment in an acid etchant, the dense ceramic base material having purity of 95 wt % or higher and exceeding 90% of a theoretical density, whereby ceramic grains existing on the surface or its vicinity of the base material are formed on the surface thereof with a plurality of protrusions.

Abstract: The invention relates to a method of creating pores in a polymer material in sheet form or a polymer layer such as a thin film with a thickness equal to around 100 nanometers, previously deposited on a metallic base. The invention further relates to a method of creating pores in a polymer material in sheet form, such as polycarbonate or any other equivalent material, the said method making it possible to obtain porous areas with controllable sizes and shapes, these areas being distributed according to densities and locations which can also be controlled.

Abstract: A method for forming a superhard polycrystalline diamond or diamond-like element with greatly improved resistance to thermal degradation without loss of impact strength. Collectively called PCD elements, these elements are formed with a binder-catalyzing material in a high-temperature, high-pressure process. The PCD element has a plurality of partially bonded diamond or diamond-like crystals forming at least one continuous diamond matrix, and the interstices among the diamond crystals forming at least one continuous interstitial matrix containing a catalyzing material. The element has a working surface and a body, where a portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material to a depth from the working surface, the remaining interstitial matrix contains the catalyzing material, causing a 950 degrees C. temperature at the working surface to be less than 750 degrees C. at the depth.

Abstract: The invention includes processes for combined polymer surface treatment and metal deposition. Processes of the invention include forming an aqueous solution containing a metal activator, such as an oxidized species of silver, cobalt, ruthenium, cerium, iron, manganese, nickel, rhodium, or vanadium. The activator can be suitably oxidized to a higher oxidation state electrochemically. Exposing a part to be plated (such as an organic resin, e.g. a printed circuit board substrate) to the solution enables reactive hydroxyl species (e.g. hydroxyl radicals) to be generated and to texture the polymer surface. Such texturing facilitates good plated metal adhesion. As part of this contacting process sufficient time is allowed for both surface texturing to take place and for the oxidized metal activator to adsorb onto said part. The part is then contacted with a reducing agent capable of reducing the metal activator to a lower ionic form, or a lower oxidation state.

Abstract: One embodiment disclosed relates to a method for sealing an active area of a non-silicon-based device on a wafer. The method includes providing a sacrificial material over at least the active area of the non-silicon-based device, depositing a seal coating over the wafer so that the seal coating covers the sacrificial material, and replacing the sacrificial material with a target atmosphere. Another embodiment disclosed relates to a non-silicon-based device sealed at the wafer level (i.e. prior to separation of the die from the wafer). The device includes an active area to be protected, a contact area, and a lithographically-formed structure sealing at least the active area and leaving at least a portion of the contact area exposed.

Abstract: A microstructured filter for a fluid, the filter having an inlet for unfiltered fluid and an outlet for filtered fluid, the filter comprising: a plurality of projections (7) which are arranged in at least two rows (3) in mutually juxtaposed relationship and which project out of a base plate (1) and which are an integral component of the base plate, a plurality of passages (8) between the projections (7), and a cover plate which is securable to the base plate to cover the projections (7) and the passages (8), wherein the passages form a plurality of through paths from the inlet to the outlet, said inlet comprises an elongate inlet slot (5) for the unfiltered fluid, which extends over approximately the entire filter width and which is approximately as high as the projection (7) projecting out of the base plate, on the outlet side of the filter. The filter according to the invention remains operational, even if a part of the filter area is obstructed.

Abstract: A method is disclosed for the induction of a suitable band gap and electron emissive properties into a substance, in which the substrate is provided with a surface structure corresponding to the interference of electron waves. Lithographic or similar techniques are used, either directly onto a metal mounted on the substrate, or onto a mold which then is used to impress the metal. In a preferred embodiment, a trench or series of nano-sized trenches are formed in the metal.

Abstract: The present invention is directed to nanoporous metal membranes and methods of making nanoporous metal membranes from metal leaf. At least a portion of the metal leaf is freely supported by a de-alloying medium for a time effective to de-alloy the metal leaf. After the porous membrane is formed, the membrane may be re-adhered to a substrate and removed from the de-alloying medium. The de-alloying process may be thermally and electrically influenced.

Abstract: A micromechanical component having a substrate made from a substrate material having a first doping type, a micromechanical functional structure provided in the substrate and a cover layer to at least partially cover the micromechanical functional structure. The micromechanical functional structure has zones made from the substrate material having a second doping type, the zones being at least partially surrounded by a cavity, and the cover layer has a porous layer made from the substrate material.

Abstract: A method for making a forming structure for use in an apparatus for making formed polymeric film. The method comprises a multiple step process of applying a photoresist polymer to a metal base sheet, curing the polymer, acid etching the portions of the metal base sheet not covered by cured polymer to form a protrusion having an upper surface and a side wall (or walls), washing the base sheet with caustic and repeating the process as necessary, each time covering the upper surface and side wall of the protrusion with cured polymer.

Abstract: Griffin, Nigel, et al78.1081-1.3-29 Disclosed is a method for manufacturing a polycrystalline diamond or diamond-like element with greatly improved wear resistance without loss of impact strength. These elements are formed with a binder-catalyzing material in a high-temperature, high-pressure (HTHP) process. The PCD element has a body with a plurality of bonded diamond or diamond-like crystals forming a continuous diamond matrix that has a diamond volume density greater than 85%. Interstices among the diamond crystals form a continuous interstitial matrix containing a catalyzing material. The diamond matrix table is formed and integrally bonded with a metallic substrate containing the catalyzing material during the HTHP process. The diamond matrix body has a working surface, where a portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and the remaining interstitial matrix contains the catalyzing material.

Abstract: A microneedle array module is disclosed comprising a multiplicity of microneedles affixed to and protruding outwardly from a front surface of a substrate to form the array, each microneedle of the array having a hollow section which extends through its center to an opening in the tip thereof. A method of fabricating the microneedle array module is also disclosed comprising the steps of: providing etch resistant mask layers to one and another opposite surfaces of a substrate to predetermined thicknesses; patterning the etch resistant mask layer of the one surface for outer dimensions of the microneedles of the array; patterning the etch resistant mask layer of the other surface for inner dimensions of the microneedles of the array; etching unmasked portions of the substrate from one and the other surfaces to first and second predetermined depths, respectively; and removing the mask layers from the one and the other surfaces.

Abstract: A thin discontinuous layer of metal such as Au, Pt, or Au/Pd is deposited on a silicon surface. The surface is then etched in a solution including HF and an oxidant for a brief period, as little as a couple seconds to one hour. A preferred oxidant is H2O2. Morphology and light emitting properties of porous silicon can be selectively controlled as a function of the type of metal deposited, Si doping type, silicon doping level, and/or etch time. Electrical assistance is unnecessary during the chemical etching of the invention, which may be conducted in the presence or absence of illumination.

Abstract: An electroplating method includes forming a layer, the forming of the layer includes: a) contacting a substrate with a first article, the first article includes a support and a conformable mask disposed in a pattern on the support; b) electroplating a first metal from a source of metal ions onto the substrate in a first pattern, the first pattern corresponding to the complement of the conformable mask pattern; and c) removing the first article from the substrate. The method may further involve one or more of (1) selectively depositing or non-selectively depositing one or more additional materials to complete formation of the layer, (2) planarizing deposited material after each deposition or after all depositions for a layer, and/or (3) forming layers adjacent previously formed layers to build up a structure from a plurality of adhered layers. Electroplating articles and electroplating apparatus are also disclosed.

Abstract: The invention provides a method of providing a metallic orthopaedic implant with a micron or nanometer-scale surface roughness to facilitate acceptance of tissue and bone growth or apposition after implantation while maintaining the structural integrity of the orthopaedic implant. The invention also provides a metallic orthopaedic implant comprising a metallic body and metallic elements adhered to a portion of the surface of the metallic body to define a three-dimensional porous surface geometry, wherein at least some of the metallic elements have a micron or nanometer-scale surface roughness.

Abstract: An anti-microbial filter (105) for a micro-fluidic system (100) includes a silicon-based filter membrane (213) having holes (218) formed therein. The membrane (213) is formed on a substrate (211). One side of the filter membrane (213) has an anti-microbial coating (216) between the holes (218) on the filter membrane (213) and the other side can include filter supports formed from a silicon substrate. A method for making the anti-microbial filter (105) includes forming a filter membrane (213) on a substrate (211), forming holes (218) in the membrane (213) by providing a filter mask (215) and etching holes (218) through holes (222) in the mask (215). Then portions of the substrate (211) are removed from the filter membrane (213) using a masking and etching process to expose the holes (218). An anti-microbial coating is applied to the membrane (213) adjacent the holes (218).

Abstract: The invention concerns a method for producing a biomimetic membrane, a biomimetic membrane and the applications of said membrane.

Abstract: In one embodiment, a fluid ejection device comprises a substrate having a fluid slot defined from a first surface through to a second opposite surface; an ejection element formed over the first surface and that ejects fluid therefrom; and a filter having feed holes positioned over the fluid slot near the first surface. Fluid moves from the second surface through the feed holes to the ejection element. In a particular embodiment, the filter is formed of a first material that is surrounded by a second material. In another particular embodiment, the filter is formed from the back side and is formed of the same material as the substrate.

Abstract: A thin discontinuous layer of metal such as Au, Pt, or Au/Pd is deposited on a Group III-V material surface. The surface is then etched in a solution including HF and an oxidant for a preferably brief period, as little as a couple seconds to one hour. A preferred oxidant is H2O2. Morphology and light emitting properties of porous Group III-V material can be selectively controlled as a function of the type of metal deposited, doping type, doping level, metal thickness, whether emission is collected on or off the metal coated areas and/or etch time. Electrical assistance is unnecessary during the chemical etching of the invention, which may be conducted in the presence or absence of illumination.

Abstract: Complex features and fine details are created in a carbon containing work piece by photolithography. A mask layer is deposited by evaporation onto the work piece. A desired pattern is created on the mask layer. The pattern is etched into the work piece and the remaining portion of the mask layer is dissolved.

Abstract: Disclosed herewithin is an apparatus for fabricating a stent which involves processing a tubular member whereby no connection points to join the edges of a flat pattern are necessary. The process includes the steps of: a) preparing the surface of a tubular member, b) coating the outside surface of the tubular member with a photo-sensitive resist material, c) placing the tubular member in an apparatus designed to simultaneously rotate the tubular member while passing a specially configured photographic frame negative between a light source and the tubular member, d) exposing the tubular member to a photoresist developer, e) rinsing the excess developer and uncured resist from the exposed tubular member, f) sealing the inner lumen of the tubular member, and g) treating the tubular member with a chemical or electro-chemical process to remove uncovered metal. By modifying the photographic negative, this process can be employed to fabricate a virtually unlimited number of stent designs and configurations.

Abstract: A multi-layered structure, and method for producing same, which may include at least one glass layer anodically bonded to an intermediate layer. The intermediate layer may function as an anodic bonding layer, an etch stop layer, and/or a hard mask layer. A template may be formed of the multi-layered structure by forming a desired pattern of openings therein by way of, for example, etching. Such a template may, for example, be used in the alignment and adherence of spacer structures to an electrode plate during the fabrication of flat panel displays. When used in this context, the construction of such a template results in more precise control of the patterning and sizing of the holes formed therein which thereby allows for more precise placement of spacer structures as well as the use of spacer structures exhibiting relatively higher aspect ratios during the fabrication of flat panel displays.

Abstract: A method of fabricating nanosized holes with controlled geometries employs tools and methods developed in the microelectronics industry. The method exploits the fact that epitaxially grown film thicknesses can be controlled within a few atomic monolayers and that by using etching techniques, trenches and channels can be created that are only a few nanometers wide. The method involves bonding two shallow channels at an angle such that a nanopore is defined by the intersection. Thus, a nanopore-defining device includes a nanopore with dimensions that are determined by the dimensions and orientations of the intersecting channels, with the dimensions being accurately controlled within a few monolayers.

Abstract: An adjustable nanopore is fabricated by placing the surfaces of two planar substrates in contact, wherein each substrate contains a hole having sharp corners and edges. A corner is brought into proximity with an edge to define a triangular aperture of variable area. Ionic current in a liquid solution and through the aperture is monitored as the area of the aperture is adjusted by moving one planar substrate with respect to the other along two directional axes and a rotational axis. Piezoelectric positioners can provide subnanometer repeatability in the adjustment process. The invention is useful for characterizing, cleaving, and capturing molecules, molecular complexes, and supramolecular complexes which pass through the nanopore, and provides an improvement over previous devices in which the hole size of nanopores fabricated by etching and/or redeposition is fixed after fabrication.

Abstract: A gradational etching method for high density wafer production. The gradational etching method acts on a substrate having a first passivation layer and a second passivation layer on a top surface and a bottom surface, respectively, of the substrate. A first etching process is performed to simultaneously etch the substrate and the first passivation layer to remove the first passivation layer. Finally, a second etching process is performed to etch the substrate to a designated depth that is used to control the thickness of the wafer after the second etching process.

Abstract: The present invention provides a matrix comprising an array of nanostructures that exhibit a variation (gradient) in physical properties (such as size or pitch) in at least one direction of the plane containing said array. A method for forming an array having a gradient property is also provided. In addition, a separation method is provided comprising the steps of: providing a matrix comprising an array of nanostructures arranged so that the array has the property of a gradient; and conducting at least one biomolecule separation process to separate biomolecules in a composition containing a plurality of biomolecules using the matrix.

Abstract: Devices for performing liquid extraction of one or more constituents from one fluid to another fluid are provided. In operation, the fluids are separated by channel structures that stabilize the interfacial boundary between the fluids allowing, for example, countercurrent flow and exchange or other flow conditions incompatible with unassisted maintenance of laminar flow. Also provided are channel structures which aid in mixing the fluids. Thin membranes may be formed using liquid extraction devices according to the invention. A process for manufacturing such devices using DRIE is described.

Abstract: Small particles of polymeric material are produced by expansion of a mixture of monomers and a propellant. The size and shape of the particles can be precisely tailored by materials selection and expansion conditions. Particles of 10 nanometers to 100 microns can be produced. If monomers exhibiting solid state reactivity are utilized, the particles thus formed can be polymerized at any time after formation. The particles produced by this method can be molecularly imprinted by incorporating a template into the particle prior to fully curing the particle, in a manner which allows selective extraction of the template from the cured particle after formation without deformation of the imprint site. A two step polymerization process allows the particles to be deposited on and adhered to a wide variety of substrates without additional agents.

Abstract: The invention relates to a hollow membrane (11) comprising two support layers arranged one above the other forming a space between them and a plurality of capillary tubes arranged between the support layers forming capillary channels for the flow of a first fluid, the space between the capillary tubes forming an internal cavity for the circulation of a second fluid around the capillary tubes, and the whole assembly being made of an organic polymer. These membranes (11) can be assembled into modules for the treatment of a fluid with intermediate porous panels (13).

Abstract: A method of forming a manifold through a substrate of a printhead substructure is disclosed. The substrate has an ink reservoir-facing side and an opposing transducer-supporting side. The transducer-supporting side of the substrate is introduced to an etchant. A laser beam is used to irradiate the etchant contacting side of the substrate. The irradiated areas of the substrate are thereby etched to define a first portion of the manifold therein. A second portion of the manifold is formed, preferably by sand blasting, to connect to the first portion. A printhead substructure that includes a substrate having a manifold formed according to the method is also disclosed.

Abstract: An etchant and a method for roughening a copper surface each capable of permitting copper with roughened surface which exhibits acid resistance and permits a copper conductive pattern and an outer layer material to be firmly bonded to each other therethrough in manufacturing of a printed wiring board to simplify the manufacturing. The etchant may contain an oxo acid such as sulfuric acid, peroxide such as hydrogen peroxide and an auxiliary component such as an azole and chlorine. The azole may comprise benzotriazole (BTA). The chlorine may be in the form of sodium chloride (NaCl). The etchant permits a copper surface to be roughened in an acicular manner.

Abstract: A method is provided for plasma ashing to remove photoresist remnants and etch residues that are formed during preceding plasma etching of dielectric layers. The ashing method uses a two-step plasma process involving an oxygen-containing gas, where low or zero bias is applied to the substrate in the first cleaning step to remove significant amount of photoresist remnants and etch residues from the substrate, in addition to etching and removing detrimental fluorocarbon residues from the chamber surfaces. An increased bias is applied to the substrate in the second cleaning step to remove the remains of the photoresist and etch residues from the substrate. The two-step process reduces the memory effect commonly observed in conventional one-step ashing processes. A method of endpoint detection can be used to monitor the ashing process.

Abstract: A micromachined membrane particle filter is formed by making holes in a silicon derivative overlayer and coating over the holes with Parylene.

Abstract: Method for making a mesh-and-plate surgical implant includes the steps of applying maskant to first and second faces of a metal sheet, selectively ablating the maskant on both faces, affixing a first tape to the first face to cover same and maskant thereon, but leaving an exposed portion for a screw hole, affixing a second tape to the second face to cover same and maskant thereon, etching the first face screw hole portion to form a crater, removing the first tape, etching the crater and other exposed portions of the first face, removing the second tape, etching opposite the crater and other exposed portions of the second face to provide openings in communication with the crater, and other second face openings extending to the first face, and removing remaining maskant to provide the implant configured to include a pliable mesh portion and a rigid plate portion, and having a screw hole therein.

Abstract: The invention is a method of introducing porous membranes into MEMS elements by supporting the membranes by frames to form an heterostructure. This is achieved by attaching to a structured or porous substrate one or more monolithically fabricated frames and membranes. Having membranes disposed on frames enables them to be batch processed and facilitates separation, handling and mounting within MEMS or nanofluidic systems. Applications include, but are not limited to, filters for gases or liquids, electron transmissive windows and scanning electron microscopy (SEM) accessible arrays of nanotest tubes containing liquid phases and other sample states. The invention includes the apparatus made by the method.

Abstract: The invention relates to a method of producing nanostructures in membranes, in which method a membrane consisting of a polymer material is irradiated with charged particles, especially ions, to produce particle tracks. The particle tracks in the membrane are etched using an etching liquid and the etching operation is stopped using a stop liquid, in such a manner that asymmetrical structures are formed. Polyimide is used as the membrane material.

Abstract: A frit for use in multi-layer microfluidic separation devices is provided. The frit comprises a polymeric membrane that may be securely bonded within the device and minimizes lateral wicking. A secure bond is ensured by treating the polymer to match its surface energy to that of the materials to which it is bound. Treatments include plasma treatment, irradiation and the application of acids.