Method and apparatus for producing a self-supporting film with a HARM structure

Abstract

We will fabricate a self-supporting film with a high aspect ratio molecular structure (HARM structure). [Solution] The second frame is positioned so that it contacts the film with a HARM structure for stretching the film to the stretched position, through an opening in the first frame, and in the stretched position the second region of the film is supported by the second frame as a self-supporting film. An evaporative wetting agent forms a contact surface between the second frame and the second region of the film. At the moment the evaporative wetting agent evaporates, it holds the film in the stretched position, thereby causing the second region of the film to adhere to the second frame. The second region of the film is separated from the first frame.

Description

Technical Field

[0001] The present invention relates to the preparation of self - supporting films of high aspect ratio molecular structures (HARM structures).

Background Art

[0002] The preparation of self - supporting films of HARM structures is a delicate process, and it is necessary to maintain the quality of the film without damaging it. Continuous attempts have been made to improve the preparation technology.

Summary of the Invention

[0003] An object of the present invention is to provide a method and an apparatus for improving the preparation of self - supporting films of high aspect ratio molecular structures (HARM structures or HARMs).

[0004] In this specification, the expression "HARM structure" or "HARM structure" may refer to a nanostructure, i.e., a structure in which one or more characteristic dimensions are on the nanometer scale, i.e., about 100 nanometers or less. In this specification, "high aspect ratio" may refer to a conductive structure in which the dimensions in two orthogonal directions are of significantly different orders of magnitude. For example, a nanostructure may have a length 50 to 10,000 times longer than its thickness and / or width. In a film of HARM structures, a number of such nanostructures can be interconnected to form a network of interconnected molecules. Considered on a macroscopic scale, the HARM network can form a solid monolithic material in which the individual molecular structures may be disoriented, or non-oriented, i.e., substantially randomly oriented. Various types of HARM structure networks can be produced in the form of thin transparent layers with appropriate resistivity, which can be understood, for example, in terms of the ratio of sheet resistivity to optical transparency. For example, any film disclosed herein may have a sheet resistance of 35 Ω / sq at 90% transmittance, although this may vary depending on the application, for example.

[0005] According to a first embodiment, a method is provided for producing a self-supporting film (thin film) of a HARM structure. The method may include the step of receiving a film of a HARM structure onto a first frame. The film of a HARM structure has a first region that adheres to the first frame and a second region that is supported across the opening of the first frame. The method includes the step of applying (depositing) an evaporative wetting agent onto the interface formed between the second frame for supporting the second region as a self-supporting film and the film of a HARM structure. The method then includes positioning the second frame by relative motion between the first frame and the second frame from the opening of the first frame to a position where the second frame contacts the film of a HARM structure for stretching the film of a HARM structure to a stretched position, in which the second region of the film of a HARM structure is supported by the second frame as a self-supporting film. This makes it possible to apply a temporary stretching force perpendicular to the film or its surface to the HARM structure film. Relative motion means that the first frame and / or the second frame may move, i.e., as long as there is relative motion between the two as described, one or both frames may move. Thus, the second frame can press the HARM structure film and / or the first frame against the first frame while the relative motion pulls the HARM structure film against it. The relative motion may consist of a single linear unidirectional motion, or it may include multiple sequential motions, further including reciprocating motion. The evaporative wetting agent forms a contact surface between the second frame and the second region of the HARM structure film. The method may further include the step of holding the film in a stretched position at the moment the evaporative wetting agent evaporates, thereby adhering the second region of the film to the second frame. Finally, the method may include the step of separating the second region of the HARM structure film from the first frame after the second region of the HARM structure film has been adhered to the second frame.

[0006] This solution makes it possible to move a film or a portion of a HARM structure from one frame to another, i.e., from a first frame to a second frame. In particular, this can be done so that the film sticks to the second frame after it has been stretched onto it. This makes it possible to introduce strain into the film, and in particular a method for introducing strain into the film plane of a self-supporting film.

[0007] Evaporative wetting agents have a dual function: firstly, a lubricating function, and secondly, a bonding function. The evaporative wetting agent lubricates the interface between the second frame and the film, allowing the film to stretch relative to the second frame. Thus, the evaporative wetting agent can reduce sliding friction between the film and the second frame, preventing the film from tearing during stretching. This is also true when the strain on the film increases. Secondly, the evaporative wetting agent can also provide a controlled method for engaging the film with the second frame. As the evaporative wetting agent evaporates, the film can bond to the second frame in its stretched position. Thus, the continuous decrease in the distance between the film and the second frame due to the evaporation of the evaporative wetting agent allows bonding to occur as a continuous process at the interface. This makes it possible to bond the film to the second frame without releasing the strain on the film.

[0008] In one embodiment, the evaporative wetting agent is an organic wetting agent. This allows for improved wetting of the HARM structure and / or the second frame compared to, for example, water, particularly when the second frame may be a hydrophobic frame. This also allows for faster evaporation compared to, for example, water. Both improved wetting and faster evaporation allow for improved bonding. If the HARM structure contains or consists of carbon nanostructures, the use of an organic wetting agent can reduce the chemical modification of the film.

[0009] In one embodiment, the evaporative wetting agent has a surface tension lower than the surface energy of the second frame. This improves the bonding between the film and the second frame.

[0010] In one embodiment, the evaporative wetting agent is a low-polarity solvent.

[0011] In one embodiment, the evaporative wetting agent has an oxygen-containing functional group.

[0012] In one embodiment, the evaporative wetting agent contains or consists of isopropyl alcohol.

[0013] In one embodiment, the evaporative wetting agent has a boiling point of 30°C to 150°C. All ambient temperature and / or pressure-dependent values ​​disclosed herein can be considered as being disclosed under NTP (normal temperature and pressure) conditions.

[0014] In one embodiment, the step of separating a second region of the HARM structure film from a first frame is carried out at least partially chemically and / or mechanically.

[0015] In one embodiment, an evaporative wetting agent is applied to the interface via a HARM structure film.

[0016] In one embodiment, the method includes a step of leveling the second frame before the film of the HARM structure is in the stretched position. This allows for sharing of the stretching force across the contact surface when they come into contact. In a further embodiment, the leveling step is performed based on optical detection of two or more edge positions of the second frame.

[0017] In one embodiment, while the HARM structured film is in a stretched position, the strain of the HARM structured film is monitored by one or more strain sensors. In a further embodiment, the one or more strain sensors include chromatic confocal sensors.

[0018] In one embodiment, the HARM structure contains or consists of carbon nanotubes.

[0019] In one embodiment, the step of separating a second region of the HARM structure film from a first frame includes separating the second region of the HARM structure film from the first region of the HARM structure film after the second region of the HARM structure film has adhered to the second frame. In a further embodiment, the second region of the HARM structure film is separated from the first region of the HARM structure film along the boundary of the second frame.

[0020] According to a second aspect, an apparatus for producing a self-supporting film of a HARM structure is disclosed. The apparatus may include clamps for clamping together a first frame for supporting a film of the HARM structure, and a retaining frame for pressing the film of the HARM structure onto the first frame to prevent delamination of the HARM structure under strain. The film of the HARM structure has a first region that is bonded to the first frame and a second region that is supported across an opening in the first frame. The apparatus includes a dispenser for applying an evaporative wetting agent to the interface formed between the film of the HARM structure and a second frame for supporting the second region of the film of the HARM structure. The apparatus may include an actuator for positioning the second frame from the opening in the first frame by relative motion between the first and second frames. The apparatus may include a separator for separating the second region of the film of the HARM structure from the first frame.

[0021] It should be understood that the above aspects and embodiments can be used in any combination. Multiple aspects and embodiments can be combined to form further embodiments of the present invention. [Brief explanation of the drawing]

[0022] Included to provide further understanding, the accompanying drawings, which form a part of this specification, illustrate embodiments and together with the description serve to explain the principles of the disclosure.

[0023] [Figure 1a] FIG. 1a shows the fabrication of a self - standing film according to an embodiment from different perspectives. [Figure 1b] FIG. 1b shows the fabrication of a self - standing film according to an embodiment from different perspectives. [Figure 2] Shows a method according to an embodiment. [Figure 3] Shows an apparatus according to an embodiment.

[0024] In the accompanying drawings, like reference numerals are used to designate like or at least functionally equivalent parts.

MODE FOR CARRYING OUT THE INVENTION

[0025] The detailed description provided below in relation to the accompanying drawings is intended as a description of embodiments and is not intended to represent the only form in which embodiments can be constructed or utilized. However, the same or equivalent functions and structures may be achieved by different embodiments.

[0026] FIGS. 1a and 1b show Example 100 of fabricating a self - standing film 110 of a HARM structure (also referred to herein as a "self - standing film" or "film" and shown as a polygonal pattern). This self - standing film can be provided, for example, as disclosed in International Publication No. WO 2010 / 086504 A1. The self - standing film can be provided such that the central portion of the film, or the network of its HARM structure, is not directly supported from below (i.e., is self - standing). The self - standing film can be supported from two or more sides, for example, by a support boundary surrounding the central portion.

[0027] A self-supporting film may be one that can exist on its own without requiring a substrate. This can be self-supporting, meaning the film has sufficient mechanical integrity and strength to maintain its structure independently. Self-supporting films can typically be formed directly as independent entities, but films grown on a substrate can also be manufactured to be self-supporting after the substrate is removed. The defining characteristic of any self-supporting film may be its ability to maintain its structure without a substrate. Whether or not a self-supporting film is formed on a substrate, it can be considered self-supporting if, after any processing step, it can exist and function independently, particularly as described above. Because a self-supporting film can maintain its structure without direct support, it does not need to be directly supported throughout its entire area. The self-supporting film provides, by itself, essential structural support for maintaining its structure, for example, its shape. This can be observed under gravity when there is no force supporting the self-supporting film. Thus, self-supporting films described herein may also be understood as self-supporting films.

[0028] HARM structures can have lengths tens to thousands of times, or even longer than, their maximum diameter. In this sense, they can be considered substantially one-dimensional structures. HARM structures may include, or consist of, carbon nanostructures, such as carbon nanotubes (CNTs) like single-walled CNTs and / or multi-walled CNTs, carbon nanobuds (molecules having fullerene molecules covalently bonded to the sides of carbon nanotubes), carbon nanoribbons, or any combination thereof. Alternatively or additionally, HARM structures may include other types of HARM structures, such as cellulose fibers, nanorods, or nanowires, such as silver nanowires. HARM structures may include, or consist of, uncoated structures and / or coated structures such as coated CNTs. Films may include, or consist of, substantially planar networks of HARM structures. HARM structures may be oriented substantially randomly within the network. HARM structures may be conductive HARM structures.

[0029] A film of the HARM structure may be supplied and / or received on a frame, here referred to as a first frame 120. Typically, the film of the HARM structure may be supplied / received on the top surface of the first frame 120, but it should be understood that this process may also be carried out in reverse so that the film of the HARM structure is supplied / received on the bottom surface of the first frame 120. Similarly, this process may also be carried out by positioning the first frame vertically or at any angle to the horizontal plane so that the film of the HARM structure is supplied / received on the surface of the first frame 120, which here is an entire side or a partial side of the first frame 120. Here, this process is generally described for a film of the HARM structure supplied / received on the top surface of the first frame 120, and any changes to this arrangement may be made as appropriate.

[0030] The first frame 120 may be provided on a chuck (not shown), which also allows for alignment of the first frame 120. The first frame 120 has an opening (shown as covered by the film 110), through which the film is supported as a self-supporting film. The opening may be at the center of the first frame 120. The frame may include a boundary 122 surrounding the opening. The opening may be symmetrical with respect to the rest of the first frame 120 and / or the boundary. The first frame 120 allows the film to be provided on the first frame 120 such that the film has a first region 112 that adheres to the first frame 120, for example, the boundary (for clarity, the first region is not shown in Figure 1, but can be considered to extend over the boundary of the first frame 120 as shown). The first region may correspond to the boundary of the film, which may be fully supported over the boundary of the first frame 120, or it may extend partially across the opening. The film may then have a second region 114 supported across the opening of the first frame 120. The second region can be considered a freestanding region supported (initially) by the first region. Thus, the second region is, for example, delimited by the first region. When the film is stationary on the first frame 120, the first and second regions may be equiplanar (i.e., coplanar). The first region may be homogeneous with respect to the second region and transition seamlessly into the second region. The first frame 120 may be a hydrophobic frame.

[0031] A second frame 130 may also be provided. The second frame 130 is sized and molded to fit through an opening in the first frame 120. This allows the second frame 130 to move through the first frame 120 from the opening (142) and into contact with the film. Alternatively or additionally, the first frame 120 may be moved for the same effect. In particular, if the first frame 120 and the second frame 130 are oriented in parallel, the second frame 130 may be positioned to fit through the first frame 120. The second frame 130 may be positioned from the opening to a position where the film of the HARM structure is stretched to a stretched position by an tensile force perpendicular to the film surface of the HARM structure film (144). The second frame 130 may also have an opening 132, through which the film, particularly a portion thereof, may also be supported as a self-supporting film. This opening may be at the center of the second frame 130. The second frame 130 may include a boundary 134 of the second frame 130 that surrounds the opening of the second frame 130. The opening of the second frame 130 may be symmetrical with respect to the rest of the second frame 130 and / or its boundary. The second frame 130 may be a hydrophobic frame.

[0032] Figure 1a shows, from a perspective view, how the second frame 130 may move relative to the film 110 and the first frame 120. In this specification, all references to the movement of the second frame 130 or the movement of the second frame 130 should be understood as meaning that the second frame 130 may move due to the relative motion between the first frame 120 and the second frame 130, i.e., only the first frame 120 may move, only the second frame 130 may move, or both the first frame 120 and the second frame 130 may move.

[0033] Figure 1b shows a side view of how the second frame 130 may be positioned, i.e., how the second frame 130 moves as described above from the opening of the first frame 120 to a position (also referred to herein as the “final position”) where it contacts the film of the HARM structure in order to stretch the film to the stretched position. The second region of the film of the HARM structure is supported by the second frame 130 as a self-supporting film. The initial position of the relative motion may be where the second frame 130 is located within the opening of the first frame 120, i.e., at or below the level of the first frame 120. The relative motion of the second frame 130 from the opening, or the entire path from the initial position to the final position, may be direct, i.e., as a single linear unidirectional motion, or may include multiple sequential motions, the sequential motions of which may include intermittent motion and / or bidirectional motion. Relative motion allows a tensile force to act perpendicularly on the HARM structure film by the second frame 130. The first frame 120 and / or the second frame 130 may be supported on a chuck.

[0034] The HARM structure film on the first frame 120 may already be stretched beforehand (even if the inventors refer to this as an unstretched position or state). In such a case, the stretching force is within the film plane of the HARM structure film. In the stretched position described herein, the stretching force is, in contrast, detached from the film plane of the HARM structure film. This can be understood as a force component perpendicular to the film plane of the HARM structure film. Thus, this may also correspond to a force component perpendicular to the first frame 120.

[0035] The first frame 120 and the second frame 130 may be provided in various shapes and sizes. The first frame 120 and / or the second frame 130 may be rectangular or elliptical frames. The first frame 120 and / or the second frame 130 may be quartz frames. In addition to, or instead of quartz, the first frame 120 and / or the second frame 130 may be PEEK (polyether ether ketone), PMMA (poly(methyl methacrylate)), PVC (polyvinyl chloride), other polymers, aluminum, stainless steel, and silicon, but may also contain or consist of one or more other materials where possible. It has been found that using quartz allows for improved thermal stability, while using polymers allows for improved adhesion between the film and the frame, for example, the second frame 130. The first frame 120 and the second frame 130 may be provided as support frames for supporting a self-supporting film.

[0036] Figure 2 shows an example of a method 200 that may be used to produce a film. As described above, the film 110 is received on the first frame 120 (210). An evaporative wetting agent (also referred to herein as the “wetting agent”) is applied to the second frame 130 (220) (also referred to herein as the “coating”). The wetting agent is applied to the interface formed between the second frame 130 and the film with the HARM structure, for example, on the boundary of the second frame 130, so that the second frame 130 can come into contact with the film with the HARM structure via the interface in order to support a second region of the film as a self-supporting film using the second frame 130. The wetting agent may be applied to the second frame 130, particularly on the side facing the film with the HARM structure, and / or to the film with the HARM structure, particularly on the side facing the second frame, for example, via the film with the HARM structure. The wetting agent may be applied partially or completely directly onto the second frame 130. Alternatively or additionally, a wetting agent may be applied partially or completely to the interface. For this purpose, the film may be indented manually and / or automatically, for example, if it is too thick or not porous for the wetting agent to pass through naturally. The wetting agent may be applied already through the film of the HARM structure before the film of the HARM structure comes into contact with the second frame. The HARM structure may be porous, allowing the wetting agent to penetrate the film and come into contact with the second frame 130.

[0037] The wetting agent may be applied downward, for example, on the second frame 130 and / or via the film of the HARM structure. Alternatively or additionally, the wetting agent may be applied upward, for example, on the film of the HARM structure. Conversely, if the process is carried out with the first frame 120 and the second frame 130 inverted, i.e., using the film of the HARM structure provided on the lower surface of the first frame, the wetting agent may be applied downward on the film of the HARM structure.

[0038] Regardless of how the wetting agent is applied to the interface, if the second frame 130 moves (230) (also referred to herein as “movement”) from the opening of the first frame 120 to contact the film, particularly to stretch the film to the stretched position, the wetting agent forms a contact surface 150 between the second frame 130 and the second region of the HARM structure film. For this purpose, the wetting agent may be provided so as to surround the opening of the second frame 130. Thus, an interface can be formed on the contact surface. The movement may be carried out alternatively or additionally by moving the first frame 120 from the opening of the first frame 120 to a position where the second frame is in contact with the film. Thus, the movement may be carried out by the relative motion of the first frame 120 and the second frame 130 by the actual movement of the first frame 120 and / or the second frame 130. At the stretched position, the second frame 120 may be sufficient in only a small amount, such as 0.5 to 2 millimeters, but it may, of course, be increased to more than that, for example, 10 millimeters or more. For example, an increase of 1.3 millimeters may result in a total stretch of 0.7% on the HARM structure film. The stretch of the HARM structure film at the stretched position (indicated as the relative increase in the length of the portion of the HARM structure film that stands upright within the first frame 120 before the second frame 130 contacts the HARM structure film when the portion of the HARM structure film is stretched to the stretched position) may be, for example, 0.2 to 2%, but may also be more or less. Contact may be formed initially through the interface via the contact surface, thereby via a wetting agent, and then the wetting agent evaporates, allowing the HARM structure film to directly contact and adhere to the second frame 130. When the second region of the HARM structured film moves from the first frame 120 to the second frame 130 while maintaining tension on the HARM structured film and its second region, the wetting agent allows the contact surface to become wet, thereby making it slippery.

[0039] The wetting agent can first provide bearing for lubrication and then evaporate to promote bonding. This reduces static friction between the film and the second frame 130 at the contact surface, allowing the film to be stretched more easily on the second frame 130. However, as the wetting agent evaporates, it becomes possible to improve adhesion between the film and the second frame 130 while the film is in the stretched position. The wetting agent can be provided as a uniform layer on the second frame 130. The wetting agent can be applied by a single droplet and / or continuous dispensing. The wetting agent may also be provided as a fluid, for example, a liquid, which can be maintained on the second frame 130 by surface tension.

[0040] Any evaporative wetting agent known to those skilled in the art may be used. In particular, the wetting agent may contain, or consist of, any of the following, alone or in any combination: alcohols, ketones, and acetate esters. The wetting agent may be organic or inorganic, or a combination thereof. The wetting agent may contain, or consist of, low-polarity solvents. These may include hydrocarbons, non-polar solvents, or other substances less polar than water. The wetting agent may have oxygen-containing functional groups. In particular, the wetting agent may contain, or consist of, isopropyl alcohol (IPA), which may be provided as a low-polarity solvent. The wetting agent may, but is not limited to, a solvent. The wetting agent may also contain, or consist of, a fluid / liquid polymer.

[0041] In general, wetting agents may contain water. In particular, wetting agents may contain, or consist of, two or more components, such as an evaporative component, such as water, and an adhesive component, such as an adhesive. As an example, a wetting agent may contain, or consist of, a water-activated polyurethane adhesive. Polyurethane adhesives can bond well to both CNT films and metals, and they can harden after the water has been removed, for example, by evaporation. A humidity sensor, such as a hygrometer placed near or around the bonding area, can be used to monitor whether water is still present. One simple method is to periodically measure the weight of the entire system: once the weight stabilizes and no further weight loss is detected, the water can be considered to have completely evaporated.

[0042] The wetting agent may have a surface tension lower than the surface tension of water and / or the surface energy of the second frame 130. The wetting agent may have a boiling point of at least 30°C and / or up to 150°C (NTP), but may also be lower or higher. Surface energy can be measured by contact angle measurement. This method involves measuring the contact angle formed by a droplet of liquid on the surface of the material. The contact angle may be influenced by the balance between adhesive and cohesive forces at the solid-liquid interface. The procedure involves placing a droplet of a known liquid on the surface of the material and measuring the contact angle using an optical instrument. The shape of the droplet provides information about the surface energy. Alternatively, surface energy and / or surface tension can be measured by a dyne test and expressed in dynes per centimeter (dyn / cm). This involves applying a liquid with a known surface tension to the surface of the material and observing the behavior of a droplet of liquid. This test is based on the principle that the contact angle formed by a droplet on the surface of the material provides information about the surface energy.

[0043] The first frame 120 and the second frame 130 can be clamped together, for example, before coating, such that the second frame 130 is inside the first frame 120, particularly inside its opening. Thus, the first frame 120 and the second frame 130 can be aligned with respect to each other. Alternatively or additionally, the first frame 120 can be clamped together with the holding frame 160 to press the film of the HARM structure onto the first frame 120 to prevent delamination of the HARM structure during strain (also referred to herein as “clamp”). In all of the above cases, clamps such as vacuum clamps can be used for clamping. Vacuum clamps allow the corresponding frames 120, 130, and 160 to be held together without damaging or damaging the surfaces of the frames 120, 130, and 160. Vacuum clamps can also evenly distribute pressure across the surface of the clamped frame(s) 120, 130, and 160. Vacuum clamps also allow for full surface accessibility, making machining and / or assembly easier. Vacuum clamps enable faster setup times by eliminating the need to manually adjust and / or tighten multiple clamps. Using vacuum clamps eliminates the need for physical contact with the corresponding frame(s) 120, 130, 160, reducing the risk of contamination from oil, adhesive, or other residues that may be present on the surface of conventional clamps. Vacuum clamps allow for a uniform pressure distribution across the entire surface of the clamped frame(s) 120, 130, 160, for example, ensuring uniformity of clamping force and minimizing the risk of distortion or warping. Vacuum clamps can be easily integrated with automated systems, enabling seamless integration into CNC (computer numerical control) machining and / or robotic assembly.

[0044] The HARM structure film may be in a stretched position (240) while the evaporative wetting agent evaporates and adheres a second region of the film to the second frame 130 (also referred to herein as “adhesion”). In particular, this includes holding the HARM structure film in a stretched position at the moment the wetting agent evaporates, thereby causing the second region of the HARM structure film to adhere to the second frame 130. Since the stretched position is a specific position where adhesion occurs, the HARM structure film may be held in this specific position for a short time or it may remain there for a long time. For example, the second frame may move directly from the opening of the first frame to the final position where the HARM structure film is in the stretched position, thereby allowing the wetting agent to evaporate completely in the stretched position, or the second frame may move to the final position for a short time as the wetting agent finally evaporates, thereby causing the second region of the HARM structure film to adhere to the second frame. The film can be moved directly from the opening to the stretched position and then maintained in the stretched position until a second region of the film adheres to the second frame 130. However, it should be understood that simply maintaining the film in the stretched position is sufficient for the second region of the film to adhere to the second frame 130. Before and / or after adhesion, the second frame 130 can be moved further (relatively) to the first frame 120, and this movement may include movement to one or more additional stretched positions, for example, larger or smaller, where the stretching of the film may differ from the stretching of the film at the stretched position where the second region of the film adheres to the second frame 130. The film can be maintained in the stretched position for a threshold time for adhesion. The threshold time may be, for example, less than 30 seconds, 30 to 60 seconds, or longer than 60 seconds, depending on the circumstances.

[0045] The second frame 130 may be leveled (also referred to herein as “leveling”) before the film is in the stretched position in order to distribute the tensile force across the contact surface. This may be done before the second region adheres to the second frame 130. For leveling, the second frame 130 may be tilted until the contact surface is horizontal, i.e., until both directions (x and y directions) defining the contact surface are horizontal. Leveling may be performed based on optical sensing using one or more optical sensors. For example, for this purpose, two or more edge positions of the second frame 130 can be identified by optical sensing. In general, the strain of the film can be monitored, in particular in the stretched position. Monitoring may be performed by a non-contact method to measure the strain in situ, in particular within the boundary of the region of the second frame 130, for example, within the second region of the film. Monitoring may be performed using one or more strain sensors, in particular chromatic confocal sensors. Strain sensors(s) may be configured for xy mapping of the film or its surface. A sag model can be used to estimate the strain level. Additional in-plane strain can also be generated, for example, by creating a pressure gradient on the film and / or by applying a current bias to the film.

[0046] After the second region of the HARM structure film is adhered to the second frame 130, the second region of the HARM structure film is separated from the first frame 120 (250) (also referred to herein as “separation”). As a result, the second region of the film is provided on the second frame 130 as a self-supporting film. Separation may include, or may consist of, separating the second region of the HARM structure film from the first frame 120 by separating the first region of the HARM structure film from the first frame 120 and / or separating the second region of the HARM structure film from the first region of the HARM structure film. This may be done partially or completely by chemical, mechanical, optical or other non-mechanical means. For example, in the latter case, the HARM structure film may be chemically, mechanically or optically cut between the first region and the second region. Mechanical separation may include, for example, mechanical cutting by scissors, a laser blade (razor blade), a scalpel, die cutting, or a microtome. Mechanical separation may include solvents or other chemical treatments. Optical separation may include, for example, optical cutting by laser cutting. Other non-mechanical means may include ultrasonic cutting, electrochemical cutting, plasma cutting, focused ion beam (FIB), or water jet cutting. Separation may be carried out along boundaries such as the inner boundary of the first frame 120 and / or along boundaries such as the outer boundary of the second frame 130. Separation may also be carried out in any area of ​​the HARM structure film between the first frame 120 and the second frame 130, away from the boundaries of the first frame 120 and the boundaries of the second frame 130.

[0047] Here, the strain in the second region, particularly the in-plane strain of the second region, may be greater than the strain of the film, particularly the in-plane strain of the film, when the film is supported by the first frame 120 (e.g., in an unstretched position or state). The focal length of the laser performing the separation can be adjusted during cutting, for example, by automatic adjustment. A chromatic confocal sensor can be used to adjust the focal length and to provide a mapping of the film or its surface. As described above, the same chromatic confocal sensor can be used both for monitoring and automating the laser cutting process, as well as as a strain sensor.

[0048] Figure 3 shows, for example, an example of an apparatus for producing a self-supporting film with a HARM structure as described above. The apparatus may include any or all of the elements described below.

[0049] The apparatus may be equipped with one or more clamps 310 for clamping the first frame 120 and the retaining frame 160 together, and / or for clamping the first frame 120 and the second frame 130 together, in particular so that the second frame 130 can be clamped in the first frame 120 or within its opening. The apparatus may be configured to use clamps(s) to perform any or all of the above clamping functions. The first frame 120 and / or the second frame 130 may be placed on a chuck 312, which may also be part of the apparatus. The apparatus may be configured to automatically and / or manually clamp the corresponding frames, e.g., the first frame 120 and the second frame 130 and / or the first frame 120 and the retaining frame 160, in response to user input. This makes it possible to align the frames 120, 130, and 160, and the apparatus may also be configured to follow, for example, a set of alignment parameters. The clamp(s) may be configured to allow controlled movement of frames 120, 130, and 160 that are clamped to each other in only one direction, for example, in the direction through the opening of the first frame 120 (z-direction), which may also be considered perpendicular to the film if the film is supported on the first frame 120. The clamp(s) may comprise one or more vacuum clamps. The first frame 120 and / or the second frame 130 may be part of the apparatus or provided separately. This also applies to the retaining frame 160. The retaining frame is configured to press the film of the HARM structure onto the first frame 120 to prevent delamination of the HARM structure under strain. The retaining frame may have the same shape as the first frame 120, for example, rectangular or elliptical.

[0050] The apparatus may comprise one or more dispensers 320 for applying an evaporative wetting agent to the interface formed between the HARM structure film and the second frame 130, for example, on the second frame 130 and / or onto the HARM structure film. The apparatus may be configured to use dispensers to perform any or all of the functions related to the application described above. The apparatus may be configured to apply the evaporative wetting agent automatically and / or manually in response to user input. The dispensers may be configured to apply the wetting agent as a single droplet and / or by continuous dispensing. The dispensers may be configured to move automatically and / or manually around the film to apply the wetting agent.

[0051] The apparatus may include one or more actuators 330 for positioning the second frame 130 through an opening in the first frame 120. The one or more actuators may include, or consist of, linear actuators and / or nonlinear actuators. As described above, this can be accomplished by relative motion between the first frame 120 and the second frame 130, so the one or more actuators may be configured to move the first frame 120 and / or the second frame 130. The one or more actuators may include one or more first actuators for moving the first frame 120 and / or one or more second actuators 130 for moving the second frame. For example, the one or more actuators may include a first linear actuator for moving the second frame 130 through an opening in the first frame and / or a second linear actuator for moving the first frame 120 so that the second frame follows through the opening in the first frame 120. The apparatus may be configured to use actuators to perform any or all of the functions related to the above arrangement. The apparatus may be configured to perform relative motion automatically and / or manually in response to user input. The actuators may be configured to move linearly in a direction perpendicular to the film (z-direction) when the film is supported on the first frame 120. The actuators may comprise one or more pneumatic lifts. The apparatus may be configured to use actuators to perform any or all of the functions related to level adjustment described above. Alternatively or additionally, the apparatus may comprise one or more level adjustment actuators separate from the actuators described above for this purpose.

[0052] The apparatus may comprise one or more separators 340, such as cutters, for separating a second region of the HARM structure film from a first frame 120 and / or separating a second region of the HARM structure film from a first region of the HARM structure film. The apparatus may be configured to use separators to perform any or all of the functions related to the above separation. The apparatus may be configured to separate the second region from the first region automatically and / or manually in response to user input. Separators may be configured to move automatically and / or manually around the film to apply a wetting agent. Separators may be configured for mechanical cutting, optical cutting, chemical cutting, other non-mechanical cutting, or any combination thereof. This includes all means for the above separation. For example, separators may comprise or consist of one or more mechanical cutters, such as scissors, laser blades, scalpels, die cutters, or microtomes. The separator(s) may also comprise or consist of one or more chemical dispensers and / or laser cutters, or any means for the separator(s) described above.

[0053] The apparatus may include one or more monitoring devices 350 for monitoring the film and / or any elements, e.g., a first frame 120 and / or a second frame 130. The monitoring device(s) may include one or more optical sensing devices and / or strain sensors. The optical sensing device(s) may be configured to optically detect the level of the film, for example, by laser distance measurement. The strain sensor(s) may be configured to measure the strain of the film in two or more directions, e.g., two directions (x and y directions) of the film plane. The strain sensor(s) may include a chromatic confocal sensor that can be configured for use for the purposes described above.

[0054] An example of a process flow for producing a self-supporting film with a HARM structure is as follows: The second frame 130 is placed on the chuck without clamping. A continuous film of a wetting agent, such as IPA, is applied to the surface of the second frame 130 by dispensing multiple droplets, each with a volume of 10 microliters, at intervals of, for example, 1 cm along the entire length of the second frame 130. For example, 48 droplets can be used on the second frame 130. The droplets can be diffused and air bubbles can be removed manually, for example, with the tip of a pipette. The continuous film of wetting agent can be formed in, for example, less than 30 seconds.

[0055] As described above, applying a wetting agent serves the purpose of reducing static friction between the film and the surface of the second frame 130, thereby allowing the film to be stretched onto the second frame 130. The film can be fixed to the surface of the first frame 120 by adhesion alone. The wetting agent, in this case IPA, has the function of a lubricant or bearing.

[0056] A chuck equipped with a second frame 130 containing a wetting agent can be lowered by an actuator such as a pneumatic lift, and the first frame 120 can be positioned on the outer chuck. The wetting agent, applied as a layer, can be left for a time such as 10-20 seconds to thin out by evaporation. After this, the actuator is moved to position the second frame 130 in contact with the HARM structure film via a contact interface through relative motion, thereby placing the HARM structure film in a stretched position. In the stretched position, the second frame 130 may be separated from the first frame 120 by a distance such as 1 millimeter. All measurements given herein with respect to the second frame 130 and the first frame 120 can be considered to have been taken on the upper surface of the corresponding frame or the surface facing the HARM structure film, which could be the lower surface of the corresponding frame, for example, if the process is carried out in reverse as described above.

[0057] The strain induced in the film within the boundary of the second frame 130 can be approximated as a uniform two-dimensional elastic strain, provided that sliding friction is sufficiently small (due to lubrication by the wetting agent). The shape of the second frame 130 can minimize stress concentration points, for example, at the corners.

[0058] After the wetting agent evaporates from between the second frame 130 and the HARM structured film, the second region can be cut away from the first frame 120, thereby leaving the second region attached to the second frame 130. For this purpose, cutting can be initiated by dispensing droplets of a chemical agent, such as IPA, onto the film, for example, onto the first region, using a cutter such as a micropipette tip. The cutter can be moved along the entire length of the second frame 130, for example, in an intermittent linear motion. The chemical agent can be dispensed continuously or intermittently while moving the cutter. As the wetting agent evaporates from between the HARM structured film and the second frame 130, the impact on strain within the second region can be minimized even when the film is cut away.

[0059] Another example of a process flow for producing a self-supporting film with a HARM structure is as follows. This example can also be considered as a general description of the apparatus's function. The apparatus performs a transfer operation that includes the following: - Clamping the first frame 120 and the second frame 130 with a clamp such as a vacuum clamp, - Apply a wetting agent such as IPA to the second frame 130. - Moving the second frame 130 through the first frame 120 so that the applied wetting agent faces the first region of the frame that holds the self-supporting film of the HARM structure such as CNT, and - Cut the film while the second frame 130 is still covered with the self-supporting film (the second region of the film).

[0060] Examples of technical specifications for each step are as follows: - With respect to clamping, the clamping force on the first frame 120 and the second frame 130 can exceed the threshold force, so that none of the frames undergo any visible displacement during any step of the entire process. - With regard to dispensing, the apparatus can dispense individual single droplets of a wetting agent such as IPA in individual volumes of, for example, 5 to 50 microliters in separate steps, and / or can perform continuous dispensing of, for example, at least 1 microliter per second while moving the dispenser along the second surface. In either operating mode, a bubble-free wetting agent layer, such as an IPA layer, can be formed on the surface of the second frame 130. The preparation method can be parameterized, for example, by selecting or using the amount of wetting agent, so that the wetting agent is not locally depleted by evaporation for at least 30 seconds. - With respect to movement, the end distance (in the extended position) from the surface of the second frame 130 to the surface of the first frame 120 may be adjustable with an accuracy of at least 0.1 mm. This may be adjustable, for example, within a range of -2 mm to +10 mm. The plane of the second frame 130 may be aligned with the plane of the first frame 120, for example, such that its relative rotation is a maximum of 0.1 degrees in any direction. - With regard to application, the dispenser may be positioned to allow the wetting agent to penetrate the film, for example, by a combination of dispensing the wetting agent and performing one or more presses onto the film. The dispenser can also be positioned to dispense from beneath the HARM structure film.

[0061] The various functions described herein may be performed in different orders and / or simultaneously with each other.

[0062] Any range or device value given herein may be extended or modified without loss of intended effect unless otherwise specified. Any example may be combined with another example unless expressly prohibited.

[0063] While the subject matter is described in a language specific to its structural features and / or functions, it should be understood that the subject matter defined in the attached claims is not necessarily limited to the specific features or functions described above. Rather, the specific features and functions described above are disclosed as examples of implementing the claims, and other equivalent features and functions are included within the claims.

[0064] It will be understood that the above advantages and benefits may relate to one embodiment or to multiple embodiments. Embodiments are not limited to those that solve any or all of the described problems or that have any or all of the described advantages and benefits. Furthermore, it will be understood that references to "an" items may refer to one or more of those items.

[0065] In this specification, the term “comprising” is used to mean including the specified methods, blocks, or elements, but such blocks or elements do not constitute an exclusive list, and the methods or apparatus may include additional blocks or elements.

[0066] Numerical designations such as "first," "second," etc., are used in this text simply as a means of distinguishing parts that have similar names in the absence of such designations. Numerical designations should not be interpreted as indicating any specific order, such as priority, manufacturing order, or occurrence order in any particular structure.

[0067] While the present invention is described in conjunction with certain types of apparatus and / or methods, it should be understood that the present invention is not limited to any particular type of apparatus and / or method. While the present invention is described in conjunction with several examples, embodiments, and configurations, the present invention is not limited to these, but rather encompasses a variety of modifications and equivalent configurations that fall within the scope of the claims. Although various examples have been described above, either somewhat specifically or with reference to one or more individual embodiments, those skilled in the art can make many modifications to the disclosed examples without departing from the scope of this specification.

Claims

1. A method for producing a self-supporting film with a high aspect ratio molecular structure (HARM structure), wherein the method is: - A step of receiving a HARM structured film onto a first frame, wherein the HARM structured film has a first region that adheres to the first frame and a second region that is supported across an opening in the first frame, - A step of applying an evaporative wetting agent to the interface formed between the second frame for supporting the second region as a self-supporting film and the HARM structure film, - The relative motion between the first frame and the second frame positions the second frame from the opening of the first frame to a position where the second frame contacts the HARM structured film for stretching the HARM structured film to the stretched position, where the second region of the HARM structured film is supported by the second frame as the self-supporting film, and the evaporative wetting agent forms a contact surface between the second frame and the second region of the HARM structured film, - The step of holding the HARM structured film in the stretched position at the moment the evaporative wetting agent evaporates, thereby causing the second region of the HARM structured film to adhere to the second frame, - After the second region of the HARM structured film is adhered to the second frame, the second region of the HARM structured film is separated from the first frame. Methods that include...

2. The method according to claim 1, wherein the evaporative wetting agent is an organic wetting agent.

3. The method according to claim 1 or 2, wherein the evaporative wetting agent has a surface tension lower than the surface energy of the second frame.

4. The method according to claim 1 or 2, wherein the evaporative wetting agent is a low-polarity solvent.

5. The method according to claim 1 or 2, wherein the evaporative wetting agent has an oxygen-containing functional group.

6. The method according to claim 1 or 2, wherein the evaporative wetting agent comprises or consists of isopropyl alcohol.

7. The method according to claim 1 or 2, wherein the evaporative wetting agent has a boiling point of 30°C to 150°C (NTP).

8. The method according to claim 1 or 2, wherein the evaporative wetting agent is applied to the interface via the HARM structured film.

9. The method according to claim 1 or 2, further comprising the step of leveling the second frame before the HARM structured film is in the stretched position.

10. The method according to claim 9, wherein the level adjustment step is performed based on optical detection of two or more edge positions of the second frame.

11. The method according to claim 1 or 2, wherein while the HARM structured film is in the stretched position, the strain of the HARM structured film is monitored by one or more strain sensors.

12. The method according to claim 11, wherein the one or more strain sensors include a chromatic confocal sensor.

13. The method according to claim 1 or 2, wherein the HARM structure includes or consists of carbon nanotubes.

14. The method according to claim 1 or 2, wherein the step of separating the second region of the HARM structured film from the first frame includes separating the second region of the HARM structured film from the first region of the HARM structured film after the second region of the HARM structured film has adhered to the second frame.

15. The method according to claim 14, wherein the second region of the HARM structured film is separated from the first region of the HARM structured film along the boundary of the second frame.

16. The method according to claim 1 or 2, wherein the step of separating the second region of the HARM structured film from the first frame is carried out at least partially chemically and / or mechanically.

17. An apparatus for producing a self-supporting film with a HARM structure, wherein the apparatus is - A clamp for clamping together a first frame for supporting a HARM structure film, wherein the HARM structure film has a first region that is bonded to the first frame and a second region that is supported across an opening in the first frame; and a retaining frame for pressing the HARM structure film onto the first frame to prevent the HARM structure from peeling off under strain. - A dispenser for applying an evaporative wetting agent to the interface formed between the HARM structure film and a second frame for supporting the second region of the HARM structure film, - An actuator for positioning the second frame through the opening of the first frame by relative motion between the first frame and the second frame, - A separator for separating the second region of the HARM structure film from the first frame and A device equipped with the following features.

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