An integrated material production device combining electrospining and coating methods

Abstract

The invention relates to an integrated material production device that combines electrospinning and coating methods. In this device, the nanocomposite material is produced in situ, and the electrospun fibers are homogeneously coated in each layer.

Description

[0001] SPECIFICATION

[0002] AN INTEGRATED MATERIAL PRODUCTION DEVICE COMBINING ELECTROSPINING AND COATING METHODS

[0003] Technical Field

[0004] The invention relates to an integrated material production device that combines electrospinning and coating methods. In this device, the nanocomposite material is produced in situ, and the electrospun fibres are homogeneously coated in each layer.

[0005] Background

[0006] Electrospinning is a technique used to produce nanofibers from polymer solutions or melts and is of great importance in the fields of nanotechnology and materials science. This method is based on the principle of forming a thin jet of a liquid polymer solution under an electric field, which then solidifies into thin nanofibers. The process comprises preparing the polymer solution, applying an electric field, jet formation and refinement, and collection of the nanofibers. Nanofibers produced by electrospinning offer high surface area, porosity, and superior mechanical properties. These properties provide a wide range of applications in medical applications (e.g., wound healing, tissue engineering, and drug delivery systems), filtration (air and water filtration systems), energy (electrode materials for fuel cells and batteries), and textiles (functional and protective textile materials). Electrospinning is a versatile technique that opens the door to innovative applications in nanotechnology and materials science. Electrospinning devices are equipment used to produce nanofibers from polymer solutions or melts and comprises various components. Key components comprise a syringe and pump system that continuously feeds the polymer solution to a needle tip; the needle tip or capillary tube where the polymer solution is formed into a fine jet under an electric field; a high-voltage power supply; a collector (usually a drum or flat plate) where the nanofibers are deposited; and a control unit that controls the system.

[0007] While laboratory-grade electrospinning devices are used for small-scale research, industrial electrospinning devices offer large capacities and high productivity. Specialized electrospinning systems include coaxial electrospinning device and electro ballistic spinning device. Coaxial electrospinning device produces core-shell nanofibers by simultaneously spinning different polymer solutions, while electro ballistic spinning device enhances the mechanical properties of the nanofibers by using a high-speed rotary collector. A solvent recovery system reduces costs and environmental impact by enabling solvent evaporation and recovery. An environmental control unit increases process stability and reproducibility by controlling temperature, humidity, and other parameters. The selection of electrospinning devices varies depending on the polymer properties, the desired nanofiber structure, and the production scale. These devices are versatile and important tools that enable innovative applications in nanotechnology and materials science. Devices that combine electrospinning and coating methods offer a wide range of applications in nanotechnology and materials science. These integrated systems enable both the production of nanofibers and the coating of these nanofibers onto surfaces. Thanks to their modular design, different coating methods (e.g., electrophoretic coating, spray coating) can be combined with the electrospinning process. The devices can control temperature, humidity, and other environmental parameters to increase process repeatability and quality, and thanks to automated processes, they increase efficiency and minimize human error. Such devices can be used in medical applications such as biomedical devices, wound dressings, and tissue engineering. Integrated coating can be achieved using techniques such as coaxial electrospinning and coating, rotary jet spinning, and liquid-assisted electrospinning.

[0008] In electrospinning devices used in current technology, such as electrophoretic or spray coating, the problem can arise when the fibers are not distributed homogeneously and accumulate in clumps at a single point. In this case, the coating properties are not observed equally at every point. The primary cause of this problem is the instability of the electrostatic field. The electrospinning process requires a high-voltage electrostatic field, and instability in this field can cause fibers to disperse in random directions. Therefore, care must be taken to ensure that the voltage sources create a stable and homogeneous field. The properties of the polymer solution also affect fiber dispersion. Too high or too low a solution's viscosity, as well as an imbalance in polymer concentration, can lead to uneven fiber distribution. The formation of a web with irregular pore sizes during electrospinning results from a combination of various factors. First of all, chemical properties such as the viscosity and concentration of the polymer solution directly affect the proper formation of fibers. A viscosity that is too high or too low prevents the polymer solution from forming into filamentous structures, leading to irregular pore sizes and possibly bead-like morphology. Similarly, an imbalance in polymer concentration can affect fiber thickness and, consequently, pore sizes. The voltage used during electrospinning is also a critical factor. Insufficient or excessive voltage prevents the fibers from being properly oriented, disrupting the homogeneity of the web structure. Furthermore, the characteristics and movement of the collecting surface also affect pore sizes. An uneven or unsuitable surface causes the fibers to accumulate randomly and create irregular pore sizes. Careful control and optimization of these factors is necessary to obtain webs with homogeneous and uniform pore sizes during the electrospinning process. Conventional electrospinning methods often require high-cost, low-penetration, and non- homogeneous coating methods such as chemical vapor deposition, physical vapor deposition, ultrasonic bathing, and dipping to obtain nanocomposite structures that are intended to impart new properties to materials obtained by coating.

[0009] In the state of the art, patent application number KR20130106673A describes a hybrid coating apparatus that utilizes electrospinning and electrostatic spray deposition. The apparatus described in this document includes an electrospinning unit that collects and bonds the polymer spinning solution to a flexible substrate wrapped around a rotating drum by filamenting the polymer spinning solution with high voltage and rotating a spinning drum with a rotational drive unit. A radiation unit and an electrostatic spraying unit are spaced apart along the direction of rotation of the rotating drum. A coating layer is formed on the surface of the flexible substrate by an electrospinning unit and an electrostatic spraying unit. In the invention numbered KR20130106673 A, nanofibers obtained through electrospinning are coated using the electrostatic spray method. In the electrostatic spray method, the coating material is negatively charged, and the driving force behind its adhesion to the coated material is the discharge of its electrical charge onto the material. For this reason, in the invention numbered KR20130106673A, the material used in the coating must be electrically charged. Furthermore, it is observed that the coating is carried out simultaneously while the nanofibers are being collected on a single cylinder. Therefore, the thickness and homogeneity of the nanocomposite structure cannot be controlled.

[0010] In another state of the art, patent application CN115891183A describes a quantum dot film preparation device and method with a uniform distribution function for quantum dots. In the method described in the document, the distance between two hollow cylinders and the water-oxygen barrier film is adjusted, the production thickness of the quantum dot film is varied, and the quantum dot film is compressed during the production process by the cooperation of two guide rollers. The water-oxygen barrier films are transported by the static friction created by the cooperation of the transport rollers and the water-oxygen barrier films.

[0011] In another state of the art, patent application number KR20110078016A describes a drumshaped spinning nozzle block and an electrospinning apparatus comprising it, which allows for the production of a large-scale, uniformly pore-sized web. The drum-shaped spinning nozzle block and the electrospinning nozzle comprise a punch plate cylinder, an insulating portion, a hot wire, a shaft, and a hot air supply line.

[0012] The limitations and inadequacies of existing technical solutions, the inability to homogeneously coat nanofibers throughout the entire thickness in electrospinning devices, the inability to control the thickness and homogeneity of the nanocomposite structure, the inability to control the density and composition of the coating, the tendency for fibers to accumulate in clumps at a single point, the limited surface area covered, the formation of a web with irregular pore sizes, the uneven observation of coating properties at all points, and the high cost of low-penetration and non-homogeneous coating methods such as chemical vapor deposition, physical vapor deposition, ultrasonic bathing, immersion, etc. used to obtain nanocomposite structures, have necessitated development in this area.

[0013] Brief Description and Objectives of the Invention

[0014] The invention relates to an integrated material production device that combines electrospinning and coating methods. In said device, the nanocomposite material is produced in situ, and the electrospun fibers are homogeneously coated in each layer.

[0015] One objective of the invention is to develop an integrated device that simultaneously performs homogeneous coating and electrospinning processes in nanofiber production. In this device, the suspension dropped onto the fiber mat is crushed between two rollers (rear and front rollers), ensuring homogeneous coating. The electrospinning and coating processes move as the cylinders rotate. Therefore, thanks to this mechanism, the coating and electrospinning processes are carried out simultaneously, ensuring a homogeneous coating on each layer of the resulting fiber mat. Another objective of the invention is to develop a device that allows coating of fibers throughout their thickness in each layer during nanofiber production. In this device, the nanocomposite material is produced in situ, and the electrospun fibers are coated in each layer. When fibers are produced on top of each other through electrospinning, complete coating is achieved along the z-axis, that is, along the fiber thickness. This allows the fibers to be coated homogeneously throughout their thickness.

[0016] One objective of the invention is to develop a device that uses a low-cost and effective method for producing nanofibers. In the device, the tape casting method is combined with the casting method known in the literature as "roll casting." Tape casting is a liquid-phase production method used in electrode and capacitor production and allows for low-thickness control. Considering the entire apparatus of the invention, this hybrid casting method has been combined with electrospinning. This provides a low-cost, effective, and thickness- controllable method for producing nanofibers.

[0017] Another objective of the invention is to develop a device that allows for controlled and homogeneous coating of nanofiber porosities. Pore size and alignment can be controlled in conventional electrospinning methods by varying parameters such as the distance between the needle and the collector, voltage, and collector rotation speed. In the device of the invention, pores are controlled by varying the same parameters without any restrictions. Thus, all polymers obtained in conventional electrospinning systems, and whose porosity control is known in the literature, can be homogeneously coated in the device in question, and nanocomposite structures can be obtained.

[0018] Another objective of the invention is to provide a mechanism that ensures uniform coating properties at every point during nanofiber production. The inventive mechanism ensures homogeneous coating by crushing the suspension dropped onto the fiber mat between the rear and front rollers.

[0019] Another objective of the invention is to solve the problem of fibers accumulating in a single point in electrospinning systems. Grounding using a slip ring in the inventive system prevents fibers from accumulating and accumulating in undesirable areas on the collector. Another objective of the invention is to develop a nanocomposite material production device that eliminates the need for electrical charging in the prior art. In this device, the coated material does not have to be electrically charged, as is the case in the prior art. The lack of a need for electrical charging offers a wide range of advantages in the selection of the material to be coated.

[0020] Another objective of the invention is to develop a production device that ensures homogeneity of the nanocomposite material. In the invention, the pressure exerted by a rear cylinder on a front cylinder, which applies pressure to a cylinder where electrospinning and coating are performed, and the distance between the two cylinders can be controlled. This controllable parameter directly affects the morphology and homogeneity of the nanocomposite material.

[0021] Brief Description of the Drawings

[0022] Figure 1. Integrated material production device combining electrospinning and coating methods.

[0023] Figure 2. Integrated material production device combining electrospinning and coating methods when the rear cylinder is spring-loaded.

[0024] Figure 3. Integrated material production device combining electrospinning and coating methods when the rear cylinder is precision retracted.

[0025] Figure 4. A side view of the integrated material production device combining electrospinning and coating methods when the rear cylinder is spring-loaded.

[0026] Figure 5. A Side view of the integrated material production device combining electrospinning and coating methods when the rear cylinder is precision retracted.

[0027] Definitions of the Elements / Parts that Make Up the Invention:

[0028] 1. Gear

[0029] 2. Front cylinder

[0030] 3. Rear cylinder

[0031] 4. Actuator

[0032] 5. Rotating electrical conductor (slipring)

[0033] 6. High-voltage power supply

[0034] 7. Rail

[0035] 8. Spring 9. (movable) Element connecting the rear cylinder to the rail

[0036] 10. (fixed) Element connecting the front cylinder to the rail

[0037] 11. Element that ensures precise retraction of the rear cylinder

[0038] Detailed Description of the Invention

[0039] The invention relates to an integrated material production device that combines electrospinning and coating methods. In this device, the nanocomposite material is produced in situ, and the electrospun fibers are homogeneously coated in each layer.

[0040] The integrated material production device, which combines the electrospinning and coating methods of the invention, comprises:

[0041] - two gears (1) connected to the ends of a front cylinder (2) and a rear cylinder (3) that rotate the cylinders in opposite directions in an integrated manner; a front cylinder (2), to which a rotating electrical conductor (5) is connected, where the electrospinning and dripping processes are carried out; an actuator (4) that drives the rotation of the entire device; a rear cylinder (3), to which the driving device (4) is connected, which applies pressure to the dripped suspension and distributes the suspension to the surface of the fibers that are produced by electrospinning; a rotating electrical conductor (slipring) (5) that grounds the front cylinder (2) for electrospinning; a high voltage power supply (6) that provides the necessary electric field for the electrospinning process between the needle and the front cylinder (2).

[0042] In one embodiment of the invention, the inventive device further comprises the followings when the rear cylinder (3) is spring-loaded: a rail (7) on which the rear cylinder (3) moves on a single-axis; a spring (8) that pushes the rear cylinder (3) towards the front cylinder (2) and helps widen the distance between the two cylinders by stretching as the material between them thickens; a movable element (9) connecting the rear cylinder (3) to the rail (7); and a fixed element (10) connecting the front cylinder (2) to the rail (7). In another embodiment of the invention, the inventive device further comprises the followings when the rear cylinder (3) is precisely retracted: a rail (7) on which the rear cylinder (3) moves on a single-axis; a movable element (9) connecting the rear cylinder (3) to the rail (7); a fixed element (10) connecting the front cylinder (2) to the rail (7); and an element (11) that enables the rear cylinder (3) to retract precisely.

[0043] In the inventive device, the tape casting method is combined with the casting method known in the literature as "roll casting". Considering the entire device, this hybrid casting method is combined with the electrospinning method. The device comprises two cylinders. The two cylinders are connected to each other at their ends by a gear. This gear allows the cylinders to rotate in opposite directions, creating a rolling mill. The front cylinder (2) is grounded via a slip ring and serves as a collector. The electrospinning process takes place on the front cylinder. The liquid to be coated is dropped onto the electrospun fibers on the rotating collector (front cylinder) or between two cylinders. The rear cylinder (3) plays a critical role in the coating process. The suspension dropped onto the fiber mat is crushed between the two cylinders (front and rear cylinders), ensuring a homogeneous coating. The electrospinning and coating processes continue as the cylinders rotate. Therefore, thanks to this arrangement, the coating and electrospinning processes are carried out simultaneously, ensuring a homogeneous coating of the resulting fiber mat in each layer.

[0044] The cylinders are positioned so as to crush the material poured in between. The front cylinder (2) is a cylinder where the electrospinning and coating take place, and where the material is obtained. This cylinder is grounded via a rotating electrical conductor (slipring). The grounding can also be achieved with any component that makes electrical contact (wire, bearing, etc.). Using polymer material suitable for electrospinning, the electrospinning process is carried out on the front cylinder (2), where the fibers are produced. The suspension is dropped onto the front cylinder (2) using a pump or an injector. Electrospinning and dropping occur simultaneously. The rear cylinder (3) applies pressure to the dropped suspension, ensuring its distribution across the surface of the fibers produced by electrospinning. The actuator (4) that drives the rotation of the entire device is connected to the rear cylinder (3). Any type of motor or rotary device can be used as the actuator (4) that drives the rotation of the entire device. If the actuator (4) that drives the rotation of the entire device is directly connected to the cylinder, a coupling can be placed between the actuator (4) and the cylinder shaft to prevent wobbling caused by misalignment of the components. The actuator (4), which drives the rotation of the entire device, can also be connected to the shaft of the cylinder via a belt. If the inventive system is not designed with a spring-loaded or precision retraction version, a distance is left between the front cylinder (2) and the rear cylinder (3), and a soft material such as a mattress is placed on the rear cylinder (3). A hydrophobic material, such as a metal foil or flexible Teflon, is coated on the soft material to prevent it from absorbing the suspension. As the nanocomposite material thickens, the soft material thins, creating a spring effect, preventing the device from preventing the nanocomposite material from thickening. The device can also be operated without this soft material coating. However, if the inventive device is operated without the material coating, the rear cylinder (3) moves backwards on an axis perpendicular to the front cylinder (2) (on a single axis). Thus, as the nanocomposite material thickens, the rear cylinder (3) moves backwards on an axis perpendicular to the front cylinder (2), not preventing the resulting nanocomposite material from thickening. In this device, unlike the state of the art, the material being coated does not need to be electrically charged. This lack of electrical charging offers a wide range of advantages in selecting the material to be coated. In the inventive device, the pressure exerted by the rear cylinder (3), which applies pressure to the cylinder where electrospinning and coating are performed, on the front cylinder (2), and the distance between the two cylinders can be controlled. This controllable parameter directly affects the morphology and homogeneity of the nanocomposite material. The controllability of these effects gives the invention its originality. Thanks to the inventive device, electrospinning and coating can be controlled simultaneously, performed without a complex manner, and the nanocomposite structure can be practically obtained with a low budget, depending on the application area.

[0045] In the inventive device, the element (11) that ensures precise retraction of the rear cylinder is a device such as a voice coil, actuator, linear motor, piezoelectric motor, or linear motor with micron-level alignment precision.

[0046] The inventive device is designed in two different ways, using a single-axis retraction system. In one case, retraction is achieved by the spring-loaded rear cylinder (3), while in the other, the rear cylinder (3) is retracted on a single axis by a device such as a voice coil, actuator, linear motor, piezoelectric motor, or linear motor, capable of micron-level alignment.

[0047] In an embodiment of the invention, the rear cylinder (3) is spring-loaded. The rear cylinder (3) applies pressure to the front cylinder (2) by means of one or more springs attached to it. Thus, as the nanocomposite material on the front cylinder (2) thickens, the rear cylinder (3) moves backward, applying pressure to the spring. Therefore, the thickening of the produced nanocomposite material is not prevented. However, changing the spring constant directly affects the nanocomposite structure.

[0048] In another embodiment of the invention, the rear cylinder (3) is retracted in a single axis, in the opposite direction to the front cylinder (2), by a device such as a voice coil, actuator, linear motor, piezoelectric motor, or linear motor capable of micron-level alignment. In this case, the mechanism offers the advantage of autonomous thickness control, but the disadvantage is that the effect of electrospinning and coating parameters on thickness must be carefully calculated.

[0049] In the inventive device, a rotating conductive element (slipring) (5) and also a component, wire, or bearing that will make an electrical contact are used to ensure grounding in the front cylinder (2), which is the cylinder where the electrospinning and coating take place.

[0050] In the device of the invention, any type of motor, step motor, direct current motor (DC), different types of motor, or a device that provides rotational motion can be used as the actuator (4) that drives the rotation of the entire device.

[0051] In the case where the actuator (4) is directly connected to the cylinder, a coupling is placed between the actuator (4) and the cylinder shaft to prevent wobbling caused by the components' axial misalignment. The actuator (4), which drives the rotation of the entire device, can move on a single axis with a rail system to accompany the retraction movement. If the device remains stationary, a flexible coupling can be placed between them to prevent retraction. The device can also be used without anchoring the device to the ground. In one embodiment of the invention, the actuator (4) that drives the rotation of the entire device is connected to the cylinder shaft via a belt.

[0052] The operating method of the integrated material production device, which combines the electrospinning and coating methods of the invention, includes the following process steps:

[0053] (i) dropping the suspension onto the cylinder where electrospinning takes place or between two cylinders using any pump or injector device,

[0054] (ii) performing electrospinning and dripping simultaneously,

[0055] (iii) applying pressure on the dropped suspension via the rear cylinder (3) and distributing the suspension onto the surface of the fibers produced by electrospinning,

[0056] (iv) ensuring the homogeneity of the suspension dropped during coating,

[0057] (v) if a volatile liquid is used at room conditions, left the material to stand for the liquid to evaporate from the environment after the material is obtained; if no volatile liquid is used, removing the liquid forming the suspension from the composite material through heat treatment.

Claims

CLAIMS1. An integrated material production device, which combines the electrospinning and coating methods comprises:- two gears (1) connected to the ends of a front cylinder (2) and a rear cylinder (3) that rotate the cylinders in opposite directions in an integrated manner; a front cylinder (2), to which a rotating electrical conductor (5) is connected, where the electrospinning and dripping processes are carried out; an actuator (4) that drives the rotation of the entire device; a rear cylinder (3), to which the driving device (4) is connected, which applies pressure to the dripped suspension and distributes the suspension to the surface of the fibers that are produced by electrospinning; a rotating electrical conductor (slipring) (5) that grounds the front cylinder (2) for electrospinning; a high voltage power supply (6) that provides the necessary electric field for the electrospinning process between the needle and the front cylinder (2).

2. The integrated material production device according to Claim 1 further comprises the followings when the rear cylinder (3) is spring-loaded: a rail (7) on which the rear cylinder (3) moves on a single-axis; a spring (8) that pushes the rear cylinder (3) towards the front cylinder (2) and helps widen the distance between the two cylinders by stretching as the material between them thickens; a movable element (9) connecting the rear cylinder (3) to the rail (7); and a fixed element (10) connecting the front cylinder (2) to the rail (7).

3. The integrated material production device according to Claim 1 further comprises the followings when the rear cylinder (3) is precisely retracted: a rail (7) on which the rear cylinder (3) moves on a single-axis; a movable element (9) connecting the rear cylinder (3) to the rail (7); a fixed element (10) connecting the front cylinder (2) to the rail (7); and an element (11) that enables the rear cylinder (3) to retract precisely.

4. The integrated material production device according to any of the claims 1-3, wherein the actuator (4) that provides motion for the rotation of the entire device isa step motor, direct current motor (DC), different types of motor, or any other device that provides rotational motion, and is connected to the cylinder shaft via a belt.

5. The integrated material production device according to any of the claims 1-3, wherein the rotating electrical conductor (5) is a component, wire, or bearing that make any electrical contact.

6. The integrated material production device according to claim 3, wherein the element (11) that ensures the precise retraction of the rear cylinder is a device such as a voice coil, actuator, linear motor, piezoelectric motor, or linear motor with a micron-level alignment precision.

7. The integrated material production device according to claim 3, wherein the device comprises a coupling between the actuator (4) that drives the rotation of the entire device and the cylinder shaft to prevent wobbling caused by axial shifts of the components in the case where the actuator (4) that drives the rotation of the entire device is directly connected to the cylinder.

8. An operating method of the integrated material production device combining electrospinning and coating methods according to any one of claims 1-7 comprising the process steps of;(i) dropping the suspension onto the cylinder where electrospinning takes place or between two cylinders using any pump or injector device,(ii) performing electrospinning and dripping simultaneously,(iii) applying pressure on the dropped suspension via the rear cylinder (3) and distributing the suspension onto the surface of the fibers produced by electrospinning,(iv) ensuring the homogeneity of the suspension dropped during coating,(v) if a volatile liquid is used at room conditions, left the material to stand for the liquid to evaporate from the environment after the material is obtained; if no volatile liquid is used, removing the liquid forming the suspension from the composite material through heat treatment.

9. The method according to claim 8, wherein the pressure application process described in process step (iii) is provided by means of one or more springs connected to the rear cylinder (3).

10. The method according to claim 8, wherein the pressure application process described in process step (iii) is performed by retracting the rear cylinder (3) on a single axis, in the opposite direction to the front cylinder (2).

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