Portable fiber production apparatus

Abstract

Described herein is a handheld, portable apparatus for generating and depositing fibers, such as microfibers and nanofibers, on a surface. The disclosed apparatus provides an efficient, productive, and consistent operation for producing fibers. The apparatus produces nanofibers (and other size fibers) without the need for electrostatic fields and any safety parameters related to high voltage operation. The methods for generating and depositing fibers described herein employ a combination of blow-spinning and force-spinning (e.g., centrifugal spinning) techniques in the apparatus to produce fibers at a high output rate.

Description

Attorney Docket No. 6493-04302PORTABLE FIBER PRODUCTION APPARATUSSTATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0001] This invention was made with government support under grant DMR 2122178 awarded by the National Science Foundation, The government has certain rights in the invention.PRIORITY CLAIM

[0002] This application claims benefit of priority to U. S. Provisional Application Serial No. 63 / 736,990, entitled “Portable Fiber Production Apparatus,” filed December 20, 2024, and to U. S. Provisional Application Serial No. 63 / 742,946, entitled “Portable Fiber Production Apparatus,” filed January’ 8, 2025, both of which are incorporated herein by reference in their entirety.BACKGROUND1. Field of the Invention

[0003] The disclosed embodiments generally relate to the field of fiber production. Specific embodiments relate to the production of fibers of micron, sub-micron and nano size diameters using a handheld / portable device, where the production is based on a combination of blowspinning and centrifugal spinning.2. Description of the Relevant Art

[0004] Fibers having small diameters (e.g., micrometer (“micron”) to nanometer (“nano”)) are useful in a variety of fields from the clothing industry to military applications. For example, in the biomedical field, there is a strong interest in developing structures based on nanofibers (NFs) that provide scaffolding for tissue growth to effectively support living cells and as agents in wound care. In wound care the nanofibers may act as agents for inducing hemostasis, protecting against infection, or accelerating the healing process while their in situ deposition offers conformability (e.g., ability to adapt to 3D intricate sections). In the textile field, there is a strong interest in nanofibers because the nanofibers have a high surface area per unit mass that provides light, but highly wear resistant, garments. Many potential applications for small diameter fibers are being developed as the ability’ to manufacture and control their chemical and physical properties improves.Attorney Docket No. 6493-04302

[0005] Current NF making technologies focus primarily on electrospinning and Forcespinning™. Several attempts have been made to create handheld / portable devices using these technologies. Serious disadvantages, however, are still present, such as: need for high electric fields, low yield, time consuming in electrospinning, and parts rotating at high speeds (Forcespinning™).

[0006] It is known in fiber manufacturing that the electrospinning process can produce micro and nano fibers of various materials. The process of electrospinning uses electrical charge to produce fibers from a liquid. The liquid may be a solution of a material in a suitable solvent, or a melt of the material. Electrospinning requires the use of high voltage to draw out the fibers and is limited to materials that can obtain an electrical charge.

[0007] Centrifugal spinning is a method of producing fibers without the use of an electric field. In centrifugal spinning, material is ejected through one or more orifices of a rapidly spinning (e.g., high RPM) spinneret to produce fibers. The size and / or shape of the orifice from which the materials are ejected controls the size of the fibers produced. Using centrifugal spinning, microfibers and / or nanofibers may be produced.

[0008] Blow-spinning is another method for producing fibers. Blow-spinning relies on blowing air at high speed directly over the orifices where a solution or melt is being expelled. If the right conditions are met (e.g., air speed, pressure, and orientation), droplets forming at the orifices can be pulled by the blown air, elongated, and dried to generate nanofibers. This method produces high yield, though the speed of the air needs to be considerably high to achieve fine fibers: for instance, to produce nanofibers the air may reach speeds up to Mach 3.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Advantages of the present invention will become apparent to those skilled in the art with the benefit of the following detailed description of embodiments and upon reference to the accompanying drawings in which:

[0010] FIG. 1 depicts an exploded view of an apparatus for producing fibers, according to some embodiments;

[0011] FIG. 2A depicts a side view representation of an apparatus for producing fibers, according to some embodiments;

[0012] FIG. 2B depicts a side view representation of an apparatus for producing fibers with an exit duct, according to some embodiments;

[0013] FIG. 3 depicts a cross-sectional side view representation of an apparatus for producing fibers, according to some embodiments;7Attorney Docket No. 6493-04302

[0014] FIG. 4 depicts a cross-sectional perspective view representation of an apparatus for producing fibers, according to some embodiments;

[0015] FIG. 5A depicts a front side perspective view representation of an apparatus for producing fibers, according to some embodiments;

[0016] FIG. 5B depicts a front side perspective view representation of an apparatus for producing fibers with an exit duct, according to some embodiments

[0017] FIG. 6 A depicts a perspective view representation of an apparatus for producing fibers, according to some embodiments;

[0018] FIG. 6B depicts a perspective view representation of an apparatus for producing fibers with an exit duct, according to some embodiments;

[0019] FIG. 7 depicts various views of a conduit of an apparatus for producing fibers, according to some embodiments;

[0020] FIG. 8 depicts a perspective view of a spinneret of an apparatus for producing fibers, according to some embodiments;

[0021] FIGS. 9, 10, and 11 depict steps of a lock-and-key mechanism used to couple a support member to a body, according to some embodiments;

[0022] While the invention may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. The drawings may not be to scale. It should be understood, however, that the draw ings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] It is to be understood the present invention is not limited to particular devices or methods, which may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include singular and plural referents unless the content clearly dictates otherwise. Furthermore, the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not in a mandatory sense (i.e., must). Tire term “include,” and derivations thereof, mean “including, but not limited to.” The term “coupled” means directly or indirectly connected.Attorney Docket No. 6493-04302

[0024] The examples set forth herein are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.

[0025] The present disclosure pertains to a portable device that quickly and efficiently creates fine fibers, namely fibers with diameters in the nano, submicron, and / or single-digit micro scale. The disclosed apparatus is capable of safely and efficiently depositing fibers in situ onto a wound or any other target. Fine fibers have been proven effective in a wide variety of applications, such as in the development of high-efficiency filters, batteries, and scaffolds for ■wound healing to mention just a few. In some embodiments, fine fibers are biomimetic (e.g., their structure resembles that of natural tissue, so they are easily used by the body to help repair wounds). The high surface area to volume ratio of the fibers promotes hemostasis and allows for the absorption of harmful contaminants. The in-situ application of fine fibers promotes the ability to conform the scaffold to irregular geometries commonly found in slow-healing wounds.

[0026] Embodiments described herein implement a combination of centrifugal spinning and blow- spinning fabrication methods in the production of fibers (e.g., nanofibers or microfibers). Centrifugal (e.g., force) spinning involves rotating a spinneret at high RPMs (revolutions per minute) to push the fibers outward. High RPMs propel the solution away from the spinneret’s center, out through the orifices, thus generating nanofibers. This method reduces the time necessary for producing fibers compared to other methods such as electrospinning. For instance, electrospinning can take a couple of hours to obtain the yield that can be obtained in minutes using the centrifugal spinning method. Centrifugal spinning may be difficult to implement efficiently on a small scale such as the scale necessary for handheld devices.

[0027] Blow-spinning fabrication methods include using two parallel concentric fluid streams: a polymer melt or solution and a pressurized gas that flows around the polymer solution. Large air compressors, or pressurized gas are used to be able to thin the fibers. Solution and melt blow processes have been proven reliable and cost effective for micron size fibers. For nanofibers (NFs) though, the process consumes a large amount of heated gas in the case of melt blown or atmospheric temperature gas for solution processes. The energy consumptionAttorney Docket No. 6493-04302depends on the polymer characteristics, but it may be large and not feasible to scale up if nanofibers are desired. In the case of micron size fibers, the air consumption is 40-100 times as much air by weight as the polymer flow rate in order to form the fiber at high speeds. For example, for a polypropylene 3 pm size fiber, with a polymer flow rate of 0.2 gr / min / hole, the spinning speed is calculated to be 31,000 m / min (about Mach 1.5) and most of this energy is wasted. Reduction of fiber diameter will considerably increase needed speeds. For instance, studies have shown that Mach 3 is required to make nanofibers, which is basically an airplane turbine for this operation. Handheld systems for microfibers have also been shown where a pressurized container (such as a pressurized canister) is used. In these handheld systems, the polymer solution is pressurized and exits as large diameter fibers through a regular nozzle. This process may also be used with an air brush (like for painting) connected to an air compressor.

[0028] The present inventors have recognized that a system that is handheld and combines advantages of centrifugal spinning with advantages of blow-spinning may produce an efficient device for producing fibers (e.g., nanofibers or microfibers). Such a system may not require an air compressor, pressurized gas, or CO2 cartridges. In embodiments disclosed herein, the present inventors have designed a system (e.g., apparatus) that includes a combination of a blower, a support device that modifies air flow', and a spinneret (along with other components) to efficiently produce fibers.

[0029] Described herein are an apparatus and methods of creating fibers, such as microfibers and nanofibers. Tire apparatus and methods discussed herein employ blow-spinning and centrifugal spinning techniques to transform material into fibers.

[0030] FIG. 1 depicts an exploded view of an apparatus for producing fibers, according to some embodiments. In the illustrated embodiment, apparatus 100 includes handle 110, body 120, blower 130, support member 140, motor 150, spinneret 160, and exit duct 170. In various embodiments, a base of body 120 is coupled to handle 110. For instance, body 120 may include a protruding interface that mates with notches on handle 110, though other coupling means may also be contemplated. Additional embodiments may also be contemplated where body 120 and handle 110 are a single piece (e.g., a single molded piece). In some embodiments, handle 110 includes cover 112 to enclose a lower portion of the handle.

[0031] In certain embodiments, body 120 includes conduit 122 with inlet 124 at the rear of the body and outlet 126 at the front of the body. Blower 130 may be coupled to inlet 124 of conduit 122. Blower 130 may be capable of generating a flow of air and providing the flow of air into conduit 122 through inlet 124. In certain embodiments, blower 130 has a high rotational speedAttorney Docket No. 6493-04302and creates a high-pressure differential. Airflow at a high pressure is better able to overcome any impedance (resistance to airflow) it encounters (such as motor support 140 or converging nozzle 170). If airflow encountering impedance does not have enough pressure, it will slow down, stop, or even reverse its direction. The high-pressure differential (and corresponding high-pressure output) may be generated based on the internal geometry of blower 130 (e.g., the blow er may have a centrifugal-type internal geometry’ that creates high-pressure differential output). Thus, blower 130 may produce a flow of air at a high-pressure where the air flow' is a turbulent air flow' (e.g., air flow' with turbulence). One example of a maximum high-pressure output from blower 130 is a pressure of up to about 1300 Pascals. Operationally, pressures below the maximum high-pressure output may be implemented. In some embodiments, blower 130 includes backplate 131 (e.g., filter) to prevent undesired objects or particles from entering the blower.

[0032] In certain embodiments, support member 140, motor 150, and spinneret 160 are positioned inside conduit 122 of body 120. Exit duct 170 is then coupled to outlet 126 of conduit 122 to enclose support member 140, motor 150, and spinneret 160 in the body. FIG.2A depicts a side view representation of apparatus 100 when assembled, according to some embodiments. FIG. 2B depicts a side view representation of apparatus 100 w'hen assembled with exit duct 170, according to some embodiments. In the illustrated embodiments, apparatus 100 is shown assembled with body 120 coupled to handle 110 and blower 130 and, optionally, exit duct 170 coupled to the body.

[0033] FIG. 3 depicts a cross-sectional side view representation of apparatus 100 when assembled, according to some embodiments. FIG. 4 depicts a cross-sectional perspective view representation of apparatus 100 when assembled, according to some embodiments. FIG. 5A depicts a front-end view of apparatus 100 when assembled, according to some embodiments, FIG. 5B depicts a front-end view' of apparatus 100 when assembled with exit duct 170, according to some embodiments. FIG. 6A depicts a perspective view representation of apparatus 100 when assembled, according to some embodiments. FIG. 6B depicts a perspective view representation of apparatus 100 when assembled with exit duct 170, according to some embodiments. FIG. 7 depicts various views of body 120 of apparatus showing conduit 122, inlet 124, and outlet 126, according to some embodiments.

[0034] In the illustrated embodiment, handle 110, body 120, blower 130, support member 140, motor 150, spinneret 160, and exit duct 170 are shown assembled together (e.g., coupled together) according to a cross-sectional view along a central axis of apparatus 100. When assembled, blower 130 is coupled to inlet 124 of conduit 122 in body 120 and exit duct 170 isAttorney Docket No. 6493-04302coupled to outlet 126 of the conduit in the body. Support member 140, motor 150, and spinneret 160 are coupled together and positioned in conduit 122. In various embodiments, support member 140 is coupled to body 120 with motor 150 coupled to the support member and spinneret 160 coupled to the motor.

[0035] As shown in FIG. 3, a flow of air (represented by arrow 132) is generated by blower 130 and enters conduit 122 at inlet 124, The airflow generated by blower 130 is a turbulent flow of air, as described above. The flow of air then passes through openings 142 in support member 140, which are positioned circumferentially around the perimeter of motor 150. As described herein, openings 142 in support member 140 modify the turbulent flow of air (arrow 132) into a laminar flow of air (arrow 144) on the other side of the support member. The laminar flow of air (arrow 144) passes through conduit 122 around a perimeter of motor 150 and spinneret 160 inside body 120 and then outside through exit duct 170.

[0036] In certain embodiments, motor 150 and spinneret 160 are designed to have minimal impact on the laminar flow of air. For instance, motor 150 may be placed at or near the center of air flow (e.g., concentric with tire air flow) with its outer exposed surface parallel to the longitudinal axis of openings 142 in support member 140 and the laminar air flow formed by the openings. Spinneret 160 may be cone-shaped. The positions and shapes of motor 150 and spinneret 160 make them more aerodynamic and have less impact on the laminar flow of air inside conduit 122.

[0037] After the flow of air passes spinneret 160, the air is directed out of apparatus 100 through exit duct 170. In certain embodiments, as shown in FIGS. 3, 4, 5B, 6B, exit duct 170 is a converging nozzle that restricts the flow of air to a smaller area than the area inside conduit 122. Alternatively, in some embodiments, exit duct 170 is an expanding cone that expands the flow of air to a larger area than the area of the conduit. The use of either the converging nozzle or the expanding cone for exit duct 170 allows fibers to be deposited on smaller or larger areas, respectively, as is described in further detail below.

[0038] In various embodiments, support member 140 acts as a support for motor 150, an air modifier that converts turbulent air flow to laminar air flow, and a vibration dampener for the motor. Support member 140 may be coupled to body 120 through a lock-and-key mechanism. For instance, as shown in FIGS. 1 and 9-11, support member 140 may have key 146, which is a protrusion or bump on its outer perimeter that fits into lock 128 on body 120, which is a notch or other indentation in the body. In some embodiments, support member 140 may be rotated with key 146 fit into lock 128 to secure the support member to body 120.

[0039] FIGS. 9, 10, and 11 depict steps of a lock-and-key mechanism used to couple supportAttorney Docket No. 6493-04302140 member to body 120, according to some embodiments. FIG. 9 depicts a first step of the lock-and-key mechanism. In the illustrated embodiment, support member 140 includes two keys 146 (e.g., protrusions) and body 120 includes two walls forming a slot. The wall closest to the exit of body 120 features locks 128 (e.g., notches) that allow keys 146 to be inserted in the locks. The slot includes a stop that prevents keys 146 from turning further.

[0040] FIG, 10 depicts a second step of the lock-and-key mechanism. In the second step, support member 140 is inserted into body 120 in the orientation specified by keys 146 fitting into locks 128 (as shown in illustrated embodiment). FIG. 11 depicts a third step of the lock-and-key mechanism. In the third step, support member 140 is rotated 90 degrees clockwise and the two keys 146 (e.g., protrusions) turn into the slot formed by the walls of body 120. Keys 146 stop when they hit the stop in the slot. This third step secures support member 140 in place within body 120.

[0041] In certain embodiments, support member 140 includes opening 148 with base plate 149 in the opening. Motor 150 may be positioned in opening 148 and secured in place by attaching (e.g., fastening) the motor to base plate 149. For instance, base plate 149 may include holes and a combination of nuts and bolts may be used to secure motor 150 to the base plate through the holes in the base plate. Accordingly, motor 150 is positioned and supported at a center of support member 140 with openings 142 positioned around the perimeter of the motor. This positioning places motor 150 at or near a center of conduit 122, which helps improve the aerodynamics of air flow around the motor,

[0042] As shown in FIGS. 1 and 3, support member 140 includes openings 142 around the perimeter of the central opening 148. In certain embodiments, openings 142 are hexagonshaped openings that give support member 140 a honeycomb-like structure. As shown in FIG.3, openings 142 are positioned (e.g., oriented) in parallel to the air flow through conduit 122, The orientation of openings 142 relative to the air flow through conduit 122 and the size / shape of the openings allows the openings to modify the air flow. For instance, the turbulent air flow from blower 130 encountered by support member 140 is modified to laminar air flow downstream of the support member due to the size, shape, and orientation of openings 142. The reason is that airflow tends to behave more predictably in smaller areas / cross-sections, such as openings 142. Instead of being allowed to swirl around chaotically (turbulent airflow), small openings force air to move in a single, straightforward direction (laminar airflow). As described herein, the laminar air flow then allows for more consistent production of nanofibers from apparatus 100.

[0043] In certain embodiments, support member 140 is made of a flexible or elastic material.Attorney Docket No. 6493-04302For instance, support member 140 may be made of TPU (thermoplastic polyurethane). Using a flexible material for support member 140 enables the support member to provide vibration dampening for motor 150. The vibration dampening reduces noise and also increases reliability of apparatus 100.

[0044] In various embodiments, motor 150 is a brushless motor. For instance, motor 150 may be an electromagnetic motor that rotates at high RPMs by having temporary electromagnets attracted to stationary permanent magnets. The temporary magnets are turned on / off at specified frequencies to regulate the rotational speed of the motor. The specified frequencies that the temporary magnets are turned on / off at may be controlled by an ESC (electronic speed controller). In some embodiments, a microcontroller (such as an Arduino Nano controller) is used to implement code for digitally controlling the speeds of blower 130 and motor 150. For instance, a button positioned in tire opening of handle 110 may be used to control blower 130 and motor 150 may be controlled through a tri-state switch.

[0045] In certain embodiments, motor 150 spins at rotational speeds of at least 10,000 RPM.In some embodiments, motor 150 may spin at lower rotational speeds - e.g., speeds at least 8,000 RPM or at least 9,000 RPM. lire rotational speed of motor 150 may be variable over a period of time during operation. In certain contemplated embodiments, motor 150 spins at a rotational speed of 11,500 RPM. As shown in FIGS. 3 and 4, spinneret 160 is coupled (e.g., attached) to motor 150. Accordingly, spinneret 160 rotates at the rotational speed of motor 150. FIG. 8 depicts a perspective view of spinneret 160, according to some embodiments. In the illustrated embodiment, spinneret 160 includes orifices 162 across the surface of the spinneret. Note that orifices 162 may be unclear in the drawing due to the small size of the orifices and tire resolution of the drawing. For instance, orifices 162 are openings with sizes on the micro- and nanoscale for producing fibers at the micro- and nanoscale.

[0046] In various embodiments, spinneret 160 is a small, hollow and enclosed circular dome with hole 164 for a shaft of motor 150 at its center. Precursor solution (e.g., polymeric solution or fiber-producing solution) is deposited into the interior of spinneret 160 either by manually injecting the solution into the spinneret or by an external pod that pushes the solution into the spinneret via a pump. When spinneret 160 is loaded with the precursor solution, rotation of the spinneret at the high rotational speed of motor 150 causes force -spinning (e.g., centrifugal spinning) production of fibers out through orifices 162, as described herein.Operation of Apparatus

[0047] Turning back now to FIGS. 1-6B showing apparatus 100 with special focus on FIGS.Attorney Docket No. 6493-043023 and 4 showing the internal relation of components in the apparatus, operation of the apparatus for producing fibers is now described. During operation, both blower 130 and motor 150 are operated simultaneously. Blower 130 produces a high-pressure flow of air that contributes to blow-spinning production of fibers while motor 150 rotates spinneret 160 at a high rotational speed to contribute force-spinning (e.g., centrifugal) spinning production of fibers in apparatus 100. Accordingly, apparatus 100 operates to produce fibers through the combination of blowspinning and force-spinning fiber production methods to produce fibers more efficiently and at much higher outputs than available by either method alone. For example, apparatus 100 may produce fibers at outputs of at least lOx higher than either blow-spinning or force-spinning alone.|0048] As described above, spinneret 160 is loaded with a precursor solution for producing fibers. The precursor solution may be referred to, herein, as a nanofiber solution, a polymer solution, or a fiber-producing solution. During operation, spinneret 160 is rotated by motor 150 at the high rotational speed (e.g., 8,000 RPM or more) and the spinneret propels solution away from the center of the spinneret and out through orifices 162. Thus, operation of spinneret 160 in apparatus 100 provides a simple and effective technique for producing force-spun fibers from the solution in the spinneret.

[0049] As the solution exits spinneret 160, the solution encounters the flow of air generated by blower 130. As the solution exits spinneret 160 downstream of support member 140, it encounters a laminar air flow. If the airflow is below the critical airspeed necessary, the air flow from blower 130 acts to assist in the elongation and drying process of force-spun fibers in the solution exiting spinneret 160 in order for the fibers to reach their final size and shape. Indeed, unlike in traditional force-spinning, the laminar airflow from blower 130 assists in elongation by forcing fibers to follow its flow, pulling and drawing them out of body 120 in a consistent and predictable manner through a process called entrainment. If the airspeed is below the critical value, the fibers’ inertia will overcome the pulling and drawing forces of entrainment, preventing significant elongation. Note that when the elongation time is too short, the fibers may not be thin enough to be nano-sized fibers while if the elongation time is too long, the fibers may snap and form globules of solution instead of fibers. Entrainment also helps improve the precision with w-hich fibers can be deposited onto a wound after they leave the apparatus. Since the fibers are pulled and drawn into a laminar airflow, their flow will also be laminar, consistent, and predictable, allowing the user to achieve more precise, targeted fiber deposition. As before, if the airspeed is below' the critical value, the fibers’ inertia will eject them out of the current of laminar airflow, preventing them from moving in a singular, uniformAttorney Docket No. 6493-04302direction. Moreover, airflow from blower 130 assists in drying by continuously bringing in fresh, dry air to replace saturated, humid air that can no longer support evaporation, enabling continuous, almost-instant drying even in humid atmospheric conditions. If the airspeed is below the critical value, airflow from blower 130 will not be able to replace saturated, humid air fast enough, preventing significant drying. Note that if the drying time is too short, the fibers will not dry and will remain liquid while if the drying time is too long, the fibers will become brittle and crack.

[0050] Accordingly, in various embodiments, the speed of air flow from blower 130 may be adjusted as one parameter to ensure proper elongation and drying time for the force-spun fibers in the solution exiting spinneret 160. For instance, once reaching the critical air speed necessary for production of fibers, a higher speed flow of air dries the solution faster while a lower speed flow of air dries the solution slower. Thus, the air speed from blower 130 may be adjusted to assist in controlling the drying time. It should be noted that additional control of the flow of air may be provided by the size, shape, and / or orientation of openings 142 in support member 140. The size, shape, and / or orientation of openings 142 may be factors, for example, in determining the speed of air flow past spinneret 160 as well as the direction of air flow past the spinneret.

[0051] As described above, apparatus 100 adds the concept of blow-spinning fibers using blower 130 to the concept of producing fibers through force -spinning from spinneret 160. Accordingly, while force-spinning alone would rely on temperamental conditions of a quiescent surrounding environment (specifically, temperature and humidity) for elongation and drying (which thus may be unreliable depending on the conditions), the addition of blowspinning using air flow from blower 130 adds the strength of blow-spinning to the strengths of simplicity and efficiency provided by force-spinning. For instance, the concept of blowspinning using air flow from blower 130 provides a controllable flow of air (in speed, temperature, and humidity) across spinneret 160 and the solution exiting the spinneret. As mentioned above, the combination produces fibers at a much higher output (e.g., a factor of 10 ormore). For example, one experiment indicated that just centrifugal spinning produced a total of 3 mg of nanofibers while using the combination of centrifugal (force-) spinning and blowspinning produced a total of around 30 mg of nanofibers from the same precursor solution.

[0052] Further, as described herein, support member 140modifies (e.g., converts) the turbulent flow of air from blower 130 into a laminar flow of air across motor 150 and spinneret 160. Modifying laminar flow of air after support member 140 is a more predictable flow of air and is more controllable to provide consistency in the production of nanofibers from apparatus 100.Attorney Docket No. 6493-04302For instance, after the air is modified to the laminar flow of air, the air meets spinneret 160, which is designed to be aerodynamic and unintrusive to the airflow (e.g., have minimal impact / disturbance to the laminar flow of air in order to avoid creating any swirls or turbulence in the air flow).

[0053] In certain embodiments, as described above, spinneret 160 has the shape of a cone for the aerodynamic shape. Thus, when air passes over orifices 162 in spinneret 160 to elongate and dry fibers in the solution exiting the spinneret, the aerodynamic shape of the spinneret allows the air to remain laminar and predictable. The predictability of the air flow allows for fine-tuning adjustment of the parameters for improvement in elongation and drying of the fibers as discussed herein.

[0054] As described herein and shown in FIGS. 3 and 4, fibers exiting spinneret 160 will encounter the flow of air from blower 130 in conduit 122 and continue along with the flow of air out from outlet 126 into exit duct 170 of apparatus 100. Exit duct 170 may be implemented to inhibit the fast-moving air in conduit 122 from suddenly meeting the relatively calm air outside apparatus 100 (e.g., atmospheric air), which may cause swirling and / or turbulence to occur rapidly, thereby reducing the predictability and consistency of fiber production.

[0055] Accordingly, in various embodiments, exit duct 170 is implemented where the selection of the exit duct may be made depending on the desired deposition of nanofibers. In certain embodiments, the exact implementation of exit duct 170 may be modular in nature. For instance, a user may take off one type of exit duct and replace it with another exit duct depending on the use of apparatus 100. Thus, exit duct 170 is a user-selectable element and, in some instances, multiple exit ducts may be provided with apparatus to allow the user to select the appropriate exit duct for a specific use. Further, the selection of exit ducts 170 may include exit ducts with the same design but different sizes (e.g., different nozzle or cone sizes),

[0056] In some contemplated embodiments, exit duct 170 is a contracting nozzle. A contracting nozzle is shown in the illustrated embodiment of FIG. 1. The contracting nozzle design constricts the flow of air to a smaller area as the flow of air and fibers exits apparatus 100. Thus, the contracting nozzle design may assist a user in applying the nanofibers more precisely and / or to a smaller area.

[0057] In other contemplated embodiments, exit duct 170 includes expanding cone 172. The expanding cone 172 may have an inverse shape to the contracting nozzle shown in the illustrated embodiment of FIG. 1. The expanding cone design increases the flow of air to a larger area as the flow of air and fibers exits apparatus 100. Thus, the expanding nozzle design assists the user in applying nanofibers to a larger surface area (e.g., a larger wound). TheAttorney Docket No. 6493-04302expanding cone design may also make use of entrainment to increase accuracy and reduce swirling in the exiting flow of air. For instance, slits parallel to the flow of air may be added to the cone at an entrance to the cone. With the slits, the fast-moving air exiting duct 170 pulls the relatively calm air from the surroundings through the slits in an entrainment process. The air through the slits further dries the fibers and inhibits the nanofibers from expanding unpredictably. The slits may be vertical or horizontal in orientation as well as orientations in between vertical and horizontal depending on the resulting effect desired.

[0058] As described herein, apparatus 100 provides an efficient, productive, and consistent operation for producing nanofibers. Apparatus 100 produces nanofibers (and other size fibers) without the need for electrostatic fields and any safety parameters related to high voltage operation. Apparatus 100 may, for example, operate using low voltage battery power to operate blower 130 and motor 150, neither of which operate at high voltage or generate dangerous electrostatic fields. Using the components described herein, apparatus 100 is a small and portable apparatus for generating nanofibers that can be deposited on a surface. Apparatus 100 is light enough and portable enough to be handheld.

[0059] Additionally, apparatus 100, as shown in FIGS. 1-6B is designed to be modular. For instance, a user may select an exit duct 170 to be attached to body 120 based on a use case for apparatus 100. The modular design of apparatus 100 also makes the apparatus easier to disassemble for cleaning, sterilization, or maintenance. Yet further, the modular design allows a user to open apparatus 100 and easily remove / replace spinneret 160, Thus, spinnerets may be disposable elements within apparatus 100 and the apparatus may be used for multiple iterations of spinnerets.

[0060] As used herein, “fibers” represent a class of materials that are continuous filaments or that are in discrete elongated pieces, similar to lengths of thread. Fibers are of great importance in the biology of both plants and animals, such as for holding tissues together. Human uses for fibers are diverse. For example, fibers may be spun into filaments, thread, string, or rope for any number of uses. Fibers may also be used as a component of composite materials. Fibers may also be matted into sheets to make products such as paper or felt. Fibers are often used in the manufacture of other materials. For instance, fibers may be used as fillers in other matrices to impart multifunctionality to a system.

[0061] The embodiments of methods disclosed herein may be used to create, for example, nanocomposites and functionally graded materials that can be used for fields as diverse as drug delivery, wound healing, and ultrafiltration (such as electrets). In some embodiments, the methods and apparatuses disclosed herein may find application in any industry that utilizesAttorney Docket No. 6493-04302micro- to nano-sized fibers and / or micro- to nano-sized composites. Such industries include, but are not limited to, material engineering, mechanical engineering, military / defense industries, biotechnology, medical devices, tissue engineering industries, food engineering, drug delivery, electrical industries, or in ultrafiltration and / or micro-electric mechanical systems (MEMS).

[0062] In various embodiments, the material (e.g., precursor solution) used to form the fibers includes at least one polymer. Polymers that may be used include conjugated polymers, biopolymers (for wound care applications), water soluble polymers, and particle infused polymers. Examples of polymers that may be used include, but are not limited to, polypropylenes, polyethylenes, polyolefins, polystyrenes, polyesters, fluorinated polymers (fluoropolymers), polyamides, polyaramids, acrylonitrile butadiene styrene, nylons, polycarbonates, beta-lactams, block copolymers or any combination thereof. The polymer may be a synthetic (man-made) polymer or a natural polymer. The material used to form the fibers may be a composite of different polymers or a composite of a medicinal agent combined with a polymeric carrier. Specific polymers that may be used include, but are not limited to, chitosan, nylon, nylon-6, polybutylene terephthalate (PBT), polyacrylonitrile (PAN), poly(lactic acid) (PLA), poly(lactic-co-gly colic acid) (PLGA), polyglycolic acid (PGA), polyglactin, polycaprolactone (PCL), silk, collagen, poly(methyl methacrylate) (PMMA), polydioxanone, polyphenylene sulfide (PPS); polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polypropylene (PP), polyethylene oxide (PEO), acrylonitrile butadiene, styrene (ABS), and polyvinylpyrrolidone (PVP).

[0063] In certain embodiments, a hand-held fiber producing device, such as apparatus 100 described herein, may be used to provide fibers to an injury site, to stop hemorrhaging, and promote tissue mending. In various embodiments, an appropriate fiber producing material is loaded into a hand-held fiber producing device, as described above. When an injury occurs, the hand-held fiber producing device may be used to apply fibers (e.g., microfibers and / or nanofibers) to the wound site. The fibers applied to the wound site accelerate the stoppage of blood loss and promote tissue healing. The use of a handheld, portable device which could apply nanofibers in situ to conform to wounds of different geometries (2D and 3D) and therefore provide people with effective treatment to help solve, for example, the growing epidemic of chronic wounds is of great benefit.

[0064] Examples of uses of apparatus 100 include, but are not limited to, ambulances and hospital-type settings. For instance, ambulances may carry one of apparatus 100 to be used forAttorney Docket No. 6493-04302hemostatic applications. Hospitals may have multiple apparatus 100 to be used for covering any type of wound being as a regular external gauze or as scaffolds to be used internally such as internal sutures (e.g., systems to be deposited on liver / kidney cracks), on exposed skin for burn care and many more applications that have proven to respond favorable to nanofiber scaffolds. The use of a point of care device such as apparatus 100 provides numerous benefits. The portable apparatus may also be used in hospice care environments where patients fight bed sores. Spraying wounds with fibers will reduce friction and will also provide extra coverage to avoid the added suffering of abed sore. Wound care doctors may actively use apparatus 100 to treat, for example, diabetic wounds. Cancer patients may also use apparatus 100 to cover areas being radiated that then result in bums. Dressing the wounds consistently and effectively will aid in the healing process but also will reduce the risk of infection and amputation.

[0065] The apparatus described herein operates using a hybrid process that combines the strengths of two methods to address their respective weaknesses. The advantage of forcespinning is its simplicity and efficiency in forcing the polymer solution out of very' small (micron-sized) orifices, forming thin jets. A drawback of force-spinning, however, is that once the jets leave the spinneret, tire jets depend on temperamental environmental conditions, which may or may not be dry enough for evaporation. To overcome this issue at this stage, blowspinning techniques are employed: a laminar airflow with a speed above the critical threshold promotes elongation and targeted deposition through entrainment, as well as nearly instant drying by replacing saturated, humid air that can no longer support evaporation. Additionally, since force-spinning techniques have already ejected the polymer solution from within the spinneret, the required airspeed is much lower than traditional blow-spinning (below 1% of the typically required Mach 3). By combining the most effective aspects of both force- and blowspinning, the disclosed hybrid process increases fiber production reliability and boosts yield by about ten times.

[0066] Furthermore, by using a hybrid method, the process now depends on two main parameters that enable more effective optimization: spinneret RPM and airspeed (characteristic of force- and blow-spinning, respectively). Having these two main parameters (instead of just one as in force- or blow-spinning alone) takes the optimization process to a new level, allowing the apparatus to adapt to many more different environments and polymer solutions.* * *

[0067] Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilledAttorney Docket No. 6493-04302in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of tire invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.

Claims

Attorney Docket No. 6493-04302WHAT IS CLAIMED IS:

1. A handheld fiber producing apparatus, comprising:a handle for being grasped by a user;a body coupled to the handle, the body having a conduit comprising an inlet and an outlet;a blower coupled to the body at the inlet of the conduit, wherein the blower is configured to output a flow of air into the conduit, the flow of air being output as a turbulent air flow;a motor support device positioned in the conduit, wherein the motor support device is disc-shaped with a central opening for positioning of the motor and a plurality of air flow openings positioned around a perimeter of the central opening, wherein the air flow openings are oriented parallel to a direction of the flow of air in the conduit, and wherein the air flow openings are configured to modify the turbulent air flow into a laminar air flow;a motor coupled to the central opening of the motor support device;a spinneret coupled to the motor, the spinneret having a plurality of orifices positioned around a center of the spinneret, wherein the spinneret is configured to be loaded with a nanofiber solution, and wherein the spinneret is configured to be rotated circumferentially about a longitudinal axis of the flow of air through the conduit by the motor, the spinneret projecting the nanofiber solution out through the orifices and into the laminar air flow when being rotated; and an exit duct coupled to the outlet of tire conduit, wherein the exit duct is configured to direct fibers formed by an interaction of the nanofiber solution and the laminar air flow out of the apparatus onto a target surface.

2. The apparatus of claim 1, wherein the motor support device has an outer diameter corresponding to an inner diameter of the conduit with the motor support device fitting tightly in the conduit.

3. Tire apparatus of claim 1, wherein the motor support device includes a notch, and wherein the notch mates to a protrusion on an inner surface of the body.Attorney Docket No. 6493-043024. The apparatus of claim 1, wherein tlie motor support device includes a base plate in the central opening, and wherein the motor is coupled to the base plate.

5. The apparatus of claim 1, wherein the motor is positioned centrally within the conduit.

6. The apparatus of claim 1, wherein the openings in the motor support device are hexagonal-shaped openings, the hexagonal-shape being a cross-sectional shape of the openings relative the flow of air through the motor support device.

7. The apparatus of claim 1, wherein the motor support device is made of flexible material, the flexible material being configured to dampen vibrations from the motor.

8. The apparatus of claim 1, wherein the openings in the motor support device direct the laminar flow' of air across the spinneret and out through the exit duct towards the target surface as the flow of air passes through the openings.

9. The apparatus of claim 1, wherein the spinneret is cone-shaped.

10. The apparatus of claim 1, wherein the spinneret has a rotational velocity of at least 8,000 RPM11. The apparatus of claim 1, wherein the orifices in the spinneret are positioned relative to the openings in the motor support device such that elongated fibers are formed from the nanofiber solution exiting the orifices and encountering the laminar air flow'.

12. The apparatus of claim 11, w'herein the fibers are configured to elongate and dry in the laminar air flow' outside of the spinneret and before the exit duct.

13. The apparatus of claim 12, wherein the flow of air from the blower is configured to be controlled to adjust elongation and drying times of the fibers in the laminar air flow outside of the spinneret.Attorney Docket No. 6493-0430214. The apparatus of claim 1, wherein the exit duct is a converging nozzle that constricts the flow of air to a smaller area than an area of the conduit.

15. The apparatus of claim 1, wherein the exit duct is an expanding cone that expands the flow of air to a larger area than an area of the conduit.

16. The apparatus of claim 15, wherein the expanding cone includes slits on an interior surface of the expanding cone that are parallel to the flow of air through the expanding cone.

17. A method for producing nanofibers, comprising:providing a turbulent flow' of air into a conduit in a body from a blower coupled to the body at an inlet of the conduit;modifying the turbulent flow of air to a laminar flow of air at a motor support device positioned in the conduit, wherein the motor support device is disc-shaped with a central opening for positioning of a motor and a plurality of air flow' openings positioned around a perimeter of the central opening, wherein the air flow openings are oriented parallel to a direction of the flow of air in the conduit, and w'herein the air flow' openings modify the turbulent flow' of air into the laminar flow' of air;providing the laminar flow of air to a spinneret coupled to the motor, wherein the motor is coupled to the central opening of the motor support device, the spinneret having a plurality of orifices positioned around a center of the spinneret, w'herein the spinneret has been loaded with a nanofiber solution, and wherein the spinneret rotates circumferentially about a longitudinal axis of the laminar flow' of air through the conduit by the motor, the spinneret projecting the nanofiber solution out through the orifices and into the laminar air flow' when being rotated; andproducing fibers through an exi t duct coupled to an outlet of the condui t, w herein the exit duct directs fibers formed by an interaction of the nanofiber solution and the laminar flow of air out of the body onto a target surface.

18. The method of claim 17, wherein the openings in the motor support device direct the laminar flow of air across the spinneret and out through the exit duct tow ards the target surface as the flow of air passes through tire openings.Attorney Docket No. 6493-0430219. The method of claim 17, wherein the orifices in the spinneret are positioned relative to the openings in the motor support device such that elongated fibers are formed from the nanofiber solution exiting the orifices and encountering the laminar flow of air, and wherein the fibers elongate and dry in the laminar flow of air outside of the spinneret and before the exit duct.

20. The method of claim 19, further comprising controlling the flow of air from the blower to adjust elongation and drying times of the fibers in the laminar flow of air outside of the spinneret.

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