Patent Application
20240200194
Various aspects of the present invention relate generally to creating a network of fibers and more specifically to creating a network of fibers including a metallized fiber and a non-metallized fiber.
Electrospinning is a fiber production method that uses electric force to draw charged threads of polymer solutions up to fiber diameters in the order of hundreds of nanometers. Further, electrospinning does not require the use of high temperatures to produce solid threads from the polymer solutions. Electroless plating is an industrial chemical process that adds metal coatings on various materials.
According to aspects of the present disclosure, a process for creating a hybrid network of fibers comprises depositing a first polymer mixture including an electroless plating initiator onto a collector. Simultaneously, a second polymer mixture is deposited onto the collector while the first polymer mixture including the electroless plating initiator is being deposited. The second polymer mixture does not include an electroless plating initiator. A rate at which the electroless plating initiator is deposited and a rate at which the polymer solution is deposited are controlled to control a ratio of metal-doped fibers and non-metal-doped fibers in a resulting hybrid network of fibers. Likewise, rate and other operating parameters can be varied to change diameters of the resulting fibers. The metal-doped fibers are created from the electroless plating initiator and the non-metal-doped fibers are created from the polymer solution. After the fibers have been created, deposition of both the electroless plating initiator and the polymer solution is stopped. The metal-doped fibers are metalized with a metal using electroless plating.
According to more aspects of the present disclosure, the electroless plating initiator may be a metal-doped polymer solution, a metal, a metalloid, any metal chelator, or combinations thereof.
According to further aspects of the present disclosure, a process for creating a hybrid network of fibers comprises depositing a metal-doped first polymer solution onto a collector. Simultaneously, a second polymer solution is deposited onto the collector while the metal-doped first polymer solution is being deposited. The second polymer solution is not doped with a metal. A rate at which the metal-doped first polymer solution is deposited and a rate at which the second polymer solution is deposited are controlled to control a ratio of metal-doped fibers and non-metal-doped fibers in a resulting hybrid network of fibers. The metal-doped fibers are created from the metal-doped first polymer solution and the non-metal-doped fibers are created from the second polymer solution. After the fibers have been created, deposition of both the metal-doped first polymer solution and the second polymer solution is stopped. The metal-doped fibers are metalized with a metal using electroless plating.
Processes to fabricate a hybrid network of fibers are disclosed, where a first portion of the fibers are coated in metal (i.e., metallized) and a second portion includes fibers that are not coated in metal (i.e., non-metallized). The non-metallized fibers provide a different function to the overall network of fibers than the metalized fibers do. The processes can be used to fabricate networks of fibers (e.g., nano, micro or millimeter in diameter) with a portion of the fibers metalized. Owing to a high surface area to volume ratio, “one-dimensional” nanofibers and nanowires have a potential for very-high sensitivity or change in electrical characteristics. A “wire” like behavior of the metallized fiber(s) can be harnessed in integrating into an electronic device.
Processes herein create a network of fibers with both metallized fibers and non-metallized fibers using a polymer solution including an electroless plating initiator (i.e. a doping agent) (eventually resulting in metallized fibers) and using a polymer solution that is not doped with a metal (eventually resulting in non-metallized fibers). The non-metalized fibers can be used as two-dimensional (2D) and three-dimensional (3D) matrices that provide functions such as mechanical support, fluid absorption, fluid retention, scaffolding for cell attachment, enzyme immobilization, molecular handles for functionalization (e.g., DNA, aptamers, oligonucleotides, etc.). Further, the non-metalized fibers may be semiconductors, conducting polymers (e.g., polyaniline (PANI), polypyrrole (PPy), poly(3, 4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), poly-thiophene (PTH), etc.).
Control of the rates of the solutions can be facilitated by a feedback system using the doping agent as an indicator (e.g., using energy-dispersive X-ray spectroscopy, Raman spectroscopy, magnetic resonance imaging, conductivity, electro-magnetic permeability, light spectroscopy (colorimetry, fluorimetry), etc.) or with secondary doping agents that may be more easily monitored (e.g., fluorescent dyes). In this situation relative intensities and mass or volume fractions can be determined and rates adjusted. Alternatively, one set of fibers may mask the reading of the other set of fibers allowing for a ratio or masking thickness to be calculated and used to adjust rates or other electrospinning parameters.
On the other hand, the metalized fibers can be dispersed throughout the matrix for specific functions. The non-metallized portion may also be temporary, wherein it provides initial mechanical support for insertion (e.g., for microneedles) or scaffold support and may eventually degraded (biodegraded, dissolved, or otherwise removed) leaving behind metalized fibers or wires that may not have been able to be placed otherwise (e.g., a very low density network of nanofibers).
Specific functions and applications for the nanowires include: in vivo biosensors, in vitro biosensors, electrocatalysts, energy/battery applications, soft electronics, bio-actuators, nano-actuators, etc. The processes herein have been designed to use biocompatible materials, thus allowing use in bio-medical applications. One such example is wound dressings with integrated electrodes for sensing wound/tissue state and/or stimulating healing electrically. Another example incudes nanowire infused tissue scaffolds for in vitro models and implanted-tissue-engineered medical products which can stimulate cells electrically or with electronically controlled release of drugs or switchable activation/deactivation/uncaging of enzymes and proteins and DNA/RNA transcription templates. The nanowires can be used to turn on or off tissue functions like muscle contraction or hormone production as well as transfer information to and from tissues such as nervous tissues (i.e., brain-machine interface, organoids).
Additional applications/functions include addressability of sensing or actuation via crossing of conductive/metalized fibers. Using electric field focusing, gap spinning, or other alignment methods, fibers may be aligned rather than randomly oriented. By alternating the alignment of metalized fibers, so that they cross, actuation can be localized by activating/grounding specific wires or sets of wires or layers of wires to cause an affect in the fiber matrix between activated sets of wires. Similarly, changes in the conductivity between sets of wires due to changes in the hybrid fiber matrix (e.g., pH, chemical concentrations (e.g. redox mediators, metabolites, neurotransmitters, nanoparticles, quantum dots, peptides and nucleotides, degradation products, oxygen, etc.), pressure/bending/compression/stretching/displacement, from external or internal forces (e.g. pressing to cause contact or change resistance)) the fibers can be used to extend the functionality of the fiber matrix.
More examples include implantable tissue integrated sensors, where the implantable sensors (metalized components) are enclosed in a biocompatible fiber matrix (without cells) that allows integration with host tissue and can improve sensitivity and longevity and reduce discomfort. Alternatively, the non-metalized portion may provide absorption and adhesion to a biological surface as a wearable sensor (e.g., gold coated for glucose oxidase immobilization and copper based glucose sensing).
The network of fibers described herein may be used in microneedle application, both coated and infused. Non-conductive materials doped with a metal, including biopolymer materials (including hygroscopic materials which will become hydrogels when hydrated) can be coated with metal using the processes herein allowing the non-conductive materials to transmit electrical signals. Further, concerning infused microneedles, non-conductive fibers play the above roles but provide mechanical properties to penetrate a tensile strength of skin, tissue, organ, or other membrane. The interwoven fibers (which are selectively metalized, as described herein) are electrically active components. Because of their thin-size and flexibility, the metallized fibers may not have inserted correctly through the tensile skin/tissue without the non-conductive fibers providing strength. Once inserted, the non-conductive fibers may remain, absorb, or degrade leaving behind only the conductive fibers.
Other examples include layered polymer structures (e.g., composites, toes, fibers, mats, weaves, adapted fabric, etc.), security structures with unique electrical signatures (e.g., high-priced goods, bank notes, etc.), electrophoresis and chromatography separations, cell transfection, metal coordinating polymers, electrical insulation, electromagnetic interference (EMI) shielding, lightning strike resistance, microspheres, water-treatment applications (e.g., reverse osmosis, remediation of reverse osmosis, etc.), printed circuit boards with printed circuits, and time-sensitive applications where degradation of metal ions can be used to selectively mediate an environment).
Further examples include gas diffusion electrodes (GDEs) for fuel cells and batteries (where the metallized portions act as nanoelectrodes while the non-metalized portions act as wetting support matrices for holding aqueous or polymer electrolytes), partially metallized fiber or membranes (for filtering, catalysis, or electrochemical activation where a non-metallized portion of the fibers are used to provide a function like filtering or absorption and the metalized wires can be used for monitoring, activation/regeneration of the matrix), touch or pressure sensors (where the conductivity or capacitance of the sensor is due to a number of nanowires contacting each other (increasing with pressure) or decreased distance between them), and electrically activated smart polymers (e.g., polymers that when charged change their shape or flexibility or size which can be used for many novel applications).
More examples include devices with affinity receptors (antibodies/aptamers, enzymes) for sensing of analytes flowed through a porous matrix of fibers, electrothermal heating, and smart materials (change based on e.g., swelling, changes in viscosity, changes in pH).
The processes herein provide advantages over existing solutions, because the processes described herein allow for metallization of only a portion of a network of fibers and can be used with biocompatible materials. For example, existing methods for creating nanowires (e.g., template-directed synthesis, hydrothermal conversion, self-assembly, and chemical vapor deposition) are not capable of producing nanowires of a length needed to carry current (charge) over distances for the applications mentioned above, and they do not provide a way to create nanowires inside other matrices. Further, existing solutions include doping with nanoparticles, which can suffer from aggregation and vapor-phase material infiltration and polymerization or atomic layer deposition which does not offer the selectivity of the fiber(s) being metallized as do the processes described herein. “Fiber templating”, wherein electroless deposition is used in combination with electrospinning polymer solutions doped with metal nanoparticles or metallic salts does not include co-spinning of un-doped fibers to create a composite metal/non-metal network (i.e., mesh). However, the processes described herein allow for nanowires to be interleaved into a polymer material.
Turning now to the Figures, and in particular to
At 104, a second polymer mixture is deposited onto the collector at the same time that the first polymer mixture is being deposited. In other words, the first polymer mixture and the second polymer mixture are being deposited at the same time (e.g., they are co-electrospun). The second polymer mixture does not include an electroless plating initiator. In some embodiments, the second polymer mixture is deposited to create a structure (e.g., a support matrix) for the first polymer mixture including the electroless plating initiator. In various embodiments, the second polymer mixture is deposited to create a structure to direct fluids or retain fluids toward resulting metal-doped fibers created when electrospinning the first polymer mixture including the electroless plating initiator. A computer (e.g., a computer described in reference to
At 106, the rate at which the first polymer mixture including the electroless plating initiator is deposited and the rate at which the second polymer mixture is deposited onto the collector are controlled by a processor. (Note that the 102, 104, and 106 all happen simultaneously, as opposed to sequentially.) Metal-doped fibers are created from the electroless plating initiator and non-metal-doped fibers are created from the second polymer mixture. By controlling the rates at which the first polymer mixture and second polymer mixture are deposited, a ratio of metal-doped fibers to non-metal-doped fibers may be obtained. For example, if the first polymer mixture is deposited much faster than the second polymer mixture, then there will be a higher percentage of metal-doped fibers in the resulting network than non-metal-doped fibers. As discussed above, a computer (e.g., a computer described in reference to
At 108, deposition of the mixtures is stopped. They may be stopped at the same time or at different times.
At 110, the metal-doped fibers are metalized using electroless plating. Due to the metal-doped aspect of the metal-doped fibers, the electroless plating may be performed on those fibers while not being performed on the non-metal-doped fibers. In other words, the metallization of a portion of the matrix of fibers is performed after the fibers are co-spun. Any appropriate metal can be used for the metallization (e.g., gold). An advantage of this process is that the metallized nanowires are distributed throughout the network proportional to their electrospinning rate which can be controlled with relative case and does not require a separate process at the time of spinning. The metallization takes place after the fact, and electroless plating enables the metallization without a specific connection to each wire.
In some embodiments, the non-metal-doped fibers (i.e., the ones not metallized) may be removed from the network (e.g., by biodegrading).
In some embodiments, instead of the second polymer mixture not including an electroless plating initiator, the second polymer mixture includes an electroless plating initiator that is different than the electroless plating initiator of the first polymer mixture. For example, the electroless plating initiator in the first polymer mixture could be for platinum and the electroless plating initiator in the second polymer mixture could be for gold. Thus, the resulting network would have both platinum and gold after plating.
Turning now to
At 204, a second polymer solution is deposited onto the collector at the same time that the metal-doped first polymer solution is being deposited. In other words, the metal-doped first polymer solution and the second polymer solution are being deposited at the same time (e.g., they are co-electrospun). The second polymer solution is not doped with a metal. In some embodiments, the second polymer solution is deposited to create a structure (e.g., a support matrix) for the metal-doped first polymer solution. In various embodiments, the second polymer solution is deposited to create a structure to direct fluids or retain fluids toward resulting metal-doped fibers created when electrospinning the metal-doped first polymer solution. A computer (e.g., a computer described in reference to
At 206, the rate at which the metal-doped first polymer solution is deposited and the rate at which the second polymer solution is deposited onto the collector are controlled by a processor. (Note that the 202, 204, and 206 all happen simultaneously, as opposed to sequentially.) Metal-doped fibers are created from the metal-doped first polymer solution and non-metal-doped fibers are created from the second polymer solution. By controlling the rates at which the solutions are deposited, a ratio of metal-doped fibers to non-metal-doped fibers may be obtained. For example, if the metal-doped first polymer solution is deposited much faster than the second polymer solution, then there will be a higher percentage of metal-doped fibers in the resulting network than non-metal-doped fibers. As discussed above, a computer (e.g., a computer described in reference to
At 208, deposition of the first and second polymer solutions is stopped. They may be stopped at the same time or at different times.
At 210, the metal-doped fibers are metalized using electroless plating. Due to the metal-doped aspect of the metal-doped fibers, the electroless plating may be performed on those fibers while not being performed on the non-metal-doped fibers. In other words, the metallization of a portion of the matrix of fibers is performed after the fibers are co-spun. Any appropriate metal can be used for the metallization (e.g., gold). An advantage of this process is that the metallized nanowires are distributed throughout the network proportional to their electrospinning rate which can be controlled with relative ease and does not require a separate process at the time of spinning. The metallization takes place after the fact, and electroless plating enables the metallization without a specific connection to each wire.
In some embodiments, the non-metal-doped fibers (i.e., the ones not metallized) may be removed from the network (e.g., by biodegrading).
Referring to
Also connected to the I/O bus may be devices such as a graphics adapter, storage and a computer usable storage medium having computer usable program code embodied thereon. The computer usable program code may be executed to implement any aspect of the present invention, for example, to implement any aspect of any of the methods and/or system components described herein.
As will be appreciated by one skilled in the art, aspects of the present disclosure may be embodied as a system, method or computer program product. Accordingly, aspects of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer readable storage medium(s) having computer readable program code embodied thereon.
Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), Flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. A computer storage medium does not include propagating signals.
A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.
Computer program code for carrying out operations for aspects of the present disclosure may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Network using an Network Service Provider).
Aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. Aspects of the disclosure were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/432,591, filed Dec. 14, 2022, entitled “SELECTIVE POLYMER METALLIZATION FOR COMPOSITE MATERIALS”, the disclosure of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63432591 | Dec 2022 | US |
