WO2023201093A1 - Procédé hydrodynamique et de gravité de formation et de mise en forme de dispositifs microfluidiques coniques - Google Patents

Procédé hydrodynamique et de gravité de formation et de mise en forme de dispositifs microfluidiques coniques Download PDF

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Publication number
WO2023201093A1
WO2023201093A1 PCT/US2023/018739 US2023018739W WO2023201093A1 WO 2023201093 A1 WO2023201093 A1 WO 2023201093A1 US 2023018739 W US2023018739 W US 2023018739W WO 2023201093 A1 WO2023201093 A1 WO 2023201093A1
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WIPO (PCT)
Prior art keywords
fluid
microtube
tapered
core
nozzle
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PCT/US2023/018739
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English (en)
Inventor
Eleanor DERBYSHIRE
John Edward ESTES
Candace Eileen GILLETTE
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Hummingbird Nano, Inc.
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Priority claimed from US17/960,120 external-priority patent/US20230249965A1/en
Application filed by Hummingbird Nano, Inc. filed Critical Hummingbird Nano, Inc.
Publication of WO2023201093A1 publication Critical patent/WO2023201093A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/05—Filamentary, e.g. strands
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/06—Rod-shaped
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
    • B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
    • B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/30—Extrusion nozzles or dies
    • B29C48/32—Extrusion nozzles or dies with annular openings, e.g. for forming tubular articles
    • B29C48/34—Cross-head annular extrusion nozzles, i.e. for simultaneously receiving moulding material and the preform to be coated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/92—Measuring, controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2948/00—Indexing scheme relating to extrusion moulding
    • B29C2948/92—Measuring, controlling or regulating
    • B29C2948/92504—Controlled parameter
    • B29C2948/92704—Temperature

Definitions

  • the present disclosure relates to three-dimensional fabrication and shaping of micro fluidic products using hydrodynamic focusing producing a micro tube products.
  • Microfluidics devices are typically made of polymers, elastomeric materials, and combinations thereof, such as for example, a cyclo-olefin-copolymer (OC), a polymethylmethacrylate (PMMA), or a polydimethylsiloxane (PDMS) and normally consist of microfluidic channels specifically designed for manipulation, analysis and sorting of micro and nanoscale entities such as biomolecules, cells and particles.
  • OC cyclo-olefin-copolymer
  • PMMA polymethylmethacrylate
  • PDMS polydimethylsiloxane
  • Conventional fabrication of microfluidics involves complicated precesses which are expensive and limits microfluidic channel geometry.
  • PCT application PCT/US2017/020443 published as WO 2017/151915 Al provides several examples of prior art methods of producing microtubes and is incorporated by reference herein in its entirety.
  • microtubes typically have an inner diameter that can range from about 4 pm (nanometers) to about 1000 p/u (micrometers) and an outer diameter that is variable and can be controlled depending on needs.
  • the length of the microtubes can be varied depending on the end use.
  • the microtubes can have any desired cross-sectional shape, for example, circular, rectangular, square, triangular, elliptical, star or irregular.
  • Microtubes can be added or removed to make changes to the design of the microfluidic device which can be in two-dimensional (2D) or even 3D in configuration. The ability of the microtubes to be assembled and disassembled enables the fast patterning of microchannels.
  • Microtubes can be biocompatible, flexible, gas permeable and highly transparent for producing biomedical devices for various applications, e.g., flexible microfluidics, artificial skins, organs-on-chips, blood vessel and capillary network mimicking, opto-microfluidics and 3D bioreactors, among others.
  • Microtubes have been produced from polymers including a silicone elastomer, an ultraviolet sensitive polymer, a conductive polymer, a thermoplastic polymer, a thermoset polymer, a polyimide, a conductive rubber, or a polyurethane.
  • the silicone elastomer can be, for instance, poly dimethyl siloxane, phenyl-vinyl silicone, methyl-siloxane, fluoro-siloxane or platinum cured silicone rubber.
  • the ultraviolet sensitive polymer can be, for instance, MYpolymer® (a fluorinated resin with acrylate/methacrylate groups produced by MY Polymers Ltd.), styrene -acrylate-containing polymer, polyacrylate polyalkoxy silane, a positive photoresist (e.g., diazonaphthoquinone -based positive photoresist) or a negative photoresist (e.g., epoxy-based negative photoresist).
  • MYpolymer® a fluorinated resin with acrylate/methacrylate groups produced by MY Polymers Ltd.
  • styrene -acrylate-containing polymer polyacrylate polyalkoxy silane
  • a positive photoresist e.g., diazonaphthoquinone -based positive photoresist
  • a negative photoresist e.g., epoxy-based negative photoresist
  • the microtubes can be used in a biomedical device or even biomedical tissue such as an artificial skin, organ-on-chip, blood vessel mimicking device, capillary network mimicking device, opto-microfluidic device, a 3D bioreactor, drug delivery device, cell stretcher, tissue engineering scaffold, micro-pump or micro-valve.
  • Commercially available silicone tubing is normally made by extrusion of compounded elastomers mixture, which is easily converted into 3D elastomers using a cross- linking reaction (cure). Different dies and mandrels are used to produce single-lumen tubing of various size and wall thickness (defined by their outside diameter/inside diameter, or OD/ID).
  • Silicone tubing is normally translucent and with an inner diameter larger than 300 put, and fails to meet the criteria for micro/cellular scale applications. Silicon is expensive and opaque to visible and ultraviolet light, and so cannot be used with conventional optical methods of detection. Furthermore, the material is not gas permeable and is typically rigid and unsuitable in devices such as valving and actuation with peristaltic pumping is possible.
  • PDMS Polydimethylsiloxane
  • 3D micro-cavity networks are formed by either printing 3D sacrificial filament templates that are later leached away after prototyping or polymerizing the walls of the channel cavities and subsequent drainage of the uncured photopolymer precursor.
  • the techniques are impaired from the limitation in low printing resolution as the dimension of the "printed" features is limited by the sizes of the nozzle and printing pressure, or by the laser beam diameters, which make it currently a main challenge to produce features smaller than 100 pm.
  • the rough surface of printed devices also raises a concern for high-resolution imaging in the channels.
  • Micro/nano-tubes can be formed (e.g., rolled up) from thin solid films of inorganic/ organic materials at different positions once these films are released from their substrate. These microtubes have been used as 3D cell culture scaffolds and optofluidic sensor; however, the fabrication and the integration of the microtubes into microfluidic systems require complicated and expensive thermal deposition like Electron Beam deposition and photolithography facilities.
  • Microfluidic technologies such as rapid sample processing and the precise control of fluids in an assay provide a means to replace traditional experimental approaches in diagnostics and biology research.
  • microtubes of the present invention can be specifically used as elementary building blocks for microfluidic devices.
  • the fabrication procedure involves simple mechanical apparatus and cheap common materials readily available in the lab.
  • microtubes of the present invention can be easily assembled into more complex devices. It is expected that the microtubes can help to dramatically cut down the cost and time for the design, fabrication and assembly of the microfluidics systems.
  • Microchannels with circular cross-sectional shapes are currently scarce in the market. The inability to create vascular networks has hindered progress in cardiovascular tissue engineering and organs-on- chip systems.
  • Current micro-channels usually have a rectangular cross- section when fabricated using the conventional fabrication method and the fluid moving inside such channels does not mimic that of the parabolic-flow profile seen in that of circular cross-section tubes such as that of blood vessels.
  • the velocity and shear stress distribution is expected to be more isotropic in a circular tubular channel than a rectangular one with straight steep walls.
  • the cells flowing inside the latter would experience different mechanical stress depending on their relative positions in the cross-section and due to the anisotropic flow field, leading to disparate cellular activities.
  • the microtubes of the present invention can have a range of cross-sectional shapes including circular shapes with inner diameter ranging from about 500 nm to 500um and can be formed to taper having dimensions engineered for a particular volume at selected points along the tube. Cells in such a PDMS microtube will experience much more similar stress condition of a natural circulatory system than that of cuboid channels. Moreover, the velocity and vorticity fields in a circular microtube have no corner or singular regions due to the uniform circumferential wall effect.
  • the present invention as the basic building blocks for microfluidic systems, and significantly reduce the cost of fabrication as well as period of manufacture from weeks and days to hours.
  • the present invention provides ease-of-use, cost effectiveness, various cross-sectional shapes, configurability, and ease in assembling complex 2D and 3D microfluidic systems.
  • Functional micro fluidic systems can be made up of microtubes using a pre-designed template with relative ease.
  • Composite microtubes that can either comprise different materials or are multilayered, core-shell microtubes which can allow coating of these microtubes depending on the needs of the users. Additional potential applications of the microtubes of the present invention include, but are not limited to, opto-microfluidics devices, organs-on-chips systems, micro- pumps/valves for fluidic controls, controlled drug delivery systems, cell stretchers and tissue engineering scaffolds.
  • the outer diameter can be variable and have a cross-sectional shape that is circular, rectangular, square, triangular, elliptical, star, irregular, curved, or formed within a solid block of material.
  • Hydrodynamic focusing is a scientific concept for creating a flow of an outer “sheath” fluid surrounding a core fluid within a closed tube or channel.
  • Hydrodynamic focusing is involved in microfluidic applications such as ultra-fast mixers, micro-reactors, and cytometry as a technique for counting, examining and sorting microscopic particles suspended in a stream of fluid., and micro fabrication. Chemical synthesis is faster and small volumes and high area to volume ratios offer an advantage over conventional analysis methods.
  • the viscosity ratio of pd/pc (where pd is the viscosity of the core fluid and pc is the viscosity of the sheath fluid) is useful because as this ratio decreases, the dripping regime increases.
  • There is a transitional regime between droplet formation and jetting (continuous core flow) (Nunes JK, Tsai SS, Wan J, Stone HA. Dripping and jetting in microfluidic multiphase flows applied to particle and fiber synthesis. J Phys D Appl Phys. 2013;46(l l): l 14002. doi: 10.1088/0022-3727/46/11/104002).
  • the continuous phase capillary number is:
  • the Cac can also be increased by lowering the interfacial energy by techniques such as adding surfactants to the fluids, creating partially miscible fluids (Nunes JK, Tsai SS, Wan J, Stone HA. Dripping and jetting in microfluidic multiphase flows applied to particle and fiber synthesis. J Phys D Appl Phys. 2013;46(l l): l 14002. doi:10.1088/0022-3727/46/l 1/114002).
  • the radius of the core fluid can be estimated as: the radius of the core fluid and R is the channel radius (Jeong W, Kim J, Kim S, Lee S, Mensing G, Beebe DJ. Lab Chip. 2004;4:576-580).
  • the present disclosure provides a method and apparatus for forming extruded shapes having at least a hollow portion using a hydrodynamic nozzle, a curable fluid, and a focusing fluid.
  • the extruded shapes may form a tube or plurality of tubes in a bundle or porous substrate.
  • the ability to form concentric tubes and complex shapes provides a means forming high strength materials controlled release materials, and self-repair materials, etc.
  • the apparatus comprises a hydrodynamic nozzle, a curing system, a material bed, a control system and optionally a pressure system and a fluid drain system.
  • the method comprises simultaneously introducing a curable sheath fluid and a core fluid from the hydrodynamic nozzle to form a concentric extrusion, depositing at least a portion of the concentric extrusion on the material bed, and causing relative motion between the hydrodynamic nozzle and the material bed to form an extruded shape.
  • the method further comprises curing or partially curing part or all of the external curable fluid.
  • the method may optionally may introduce the concentric extrusion to pressure from the pressure system to remove the internal core fluid from the external curable fluid, and may optionally receiving the core fluid into the fluid drain system.
  • the present invention utilizes a magnetic material or material such as a ferro-fluid as a core fluid which is susceptible to magnetic fields to change the shape of the inner tube diameter.
  • Ferro fluids are composed of very small nanoscale particles (diameter usually 10 nanometers or less) of magnetite, hematite or some other compound containing iron, and a liquid (usually oil) to disperse them evenly within a carrier fluid to contribute to the overall magnetic response of the fluid.
  • the composition of a typical ferro fluid is about 5% magnetic solids, 10% surfactant and 85% carrier, by volume.
  • Particles in Ferro fluids are dispersed in a liquid, often using a surfactant, and thus Ferro fluids are colloidal suspensions. True Ferro fluids are stable.
  • Common ferro fluid surfactants are soapy surfactants used to coat the nanoparticles including, but are not limited to oleic acid, tetramethylammonium hydroxide, citric acid, soy lecithin, and combinations thereof. These surfactants prevent the nanoparticles from clumping together, so the particles cannot fall out of suspension.
  • the addition of surfactants (or any other foreign particles) decreases the packing density of the ferro particles while in its activated state, thus decreasing the fluid's on-state viscosity, resulting in a "softer” activated fluid.
  • the viscosity of ferrofluid is relatively low between 1-10 centipoise.
  • the present invention uses other fluids with a much higher viscosity that enables longer stable streams than lower viscosity fluids and with a specific gravity greater than that of the sheath fluid including glycerin and food products such as molasses.
  • the present invention to use process manipulation to provide a process whereby fluid streams are acted upon using externally applied forces including but not limited to magnetic, acoustic, heat, light, mechanical vibration, and mechanically induced deflection to produce defined features and shaping of the internal walls of the microtubes and cavities in the cured solids.
  • It is an object of the present invention to produce a micro fluidic product including precision nozzles, microfluidic chip component, capillary and sampling devices and components, precision instrumentation components (viscosity devices), textiles (hollow and solid acrylate fibers), and toys and home and office goods.
  • It is an object of the present invention to form a tapered micro tube comprising a polymer, with internal circular cross section, the tapered microtube having an inner diameter that is smaller at one end increasing to larger at the other end, with the smaller end inner diameter measuring about 500 nm to about 500 um, the larger end inner diameter measuring about 50 um to about 10 mm, the larger end to smaller end inner diameter ratio about 5:1 to about 100: 1.
  • the microtube comprises a taper geometry wherein the tapered microtube inner diameter surface is continuously increasing from the small end to the large end with the change of diameter from small to large end generally following a parabolic curve with continuously changing curvature radius, up to a maximum infinite radius at either or both ends.
  • microtube comprises a taper geometry is smoothly decreasing then increasing again in a single section or a multiplicity of sections, while the overall primary taper shape increases in inner diameter from smaller at one end to larger at the other end.
  • the microtube comprises a taper geometry having a tapered microtube inner diameter axis is that is coaxial with outer diameter axis.
  • the microtube comprises a taper geometry having a tapered microtube inner diameter axis is that is not coaxial with outer diameter axis.
  • the microtube comprises a taper geometry having a tapered microtube inner diameter axis is coaxial with the outer diameter axis in some sections and not coaxial with the outer diameter in other sections.
  • microtube overall length is from about 5 mm to about 1 m.
  • microtube outer diameter is from about 10 um to about 20 mm.
  • the outer diameter can be variable and have a cross-sectional shape that is circular, rectangular, square, triangular, elliptical, star, or irregular or block of material having a plurality of microtubes therein of a selected diameter and/or curvature.
  • It is an object of the present invention to form a tapered microtube comprising a polymer, with internal circular cross section, the tapered microtube having an inner diameter that is smaller at one end increasing to larger at the other end, with the smaller end inner diameter measuring about 500 nm to about 500 um, the larger end inner diameter measuring about 50 um to about 10 mm, the larger end to smaller end inner diameter ratio about 5:1 to about 100: 1, forming a tapered microtube with inner surface roughness about 2 to 5 nm and having an inner surface roughness about 6 to 20 nm.
  • It is an object of the present invention to form a tapered microtube comprising a polymer, with internal circular cross section, the tapered microtube having an inner diameter that is smaller at one end increasing to larger at the other end, with the smaller end inner diameter measuring about 500 nm to about 500 um, the larger end inner diameter measuring about 50 um to about 10 mm, the larger end to smaller end inner diameter ratio about 5: 1 to about 100: 1, forming a tapered microtube with inner surface roughness about 2 to 5 nm and having an inner surface roughness about 6 to 20 nm, wherein said microtube(s) are embedded in a polymer of a particular size, shape, thickness or form suitable for use with another device.
  • It is an object of the present invention to form a tapered microtube comprising a polymer, with internal circular cross section, the tapered microtube having an inner diameter that is smaller at one end increasing to larger at the other end, with the smaller end inner diameter measuring about 500 nm to about 500 um, the larger end inner diameter measuring about 50 um to about 10 mm, the larger end to smaller end inner diameter ratio about 5: 1 to about 100: 1, forming a tapered microtube with inner surface roughness about 2 to 5 nm and having an inner surface roughness about 6 to 20 nm, further including means for cooperative permanent or temporary engagement with other devices providing a fluid tight connection.
  • a tapered microtube comprising a polymer, with internal circular cross section, the tapered microtube having an inner diameter that is smaller at one end increasing to larger at the other end, with the smaller end inner diameter measuring about 500 nm to about 500 um, the larger end inner diameter measuring about 50 um to about 10 mm, the larger end to smaller end inner diameter ratio about 5: 1 to about 100: 1, forming a tapered microtube with inner surface roughness about 2 to 5 nm and having an inner surface roughness about 6 to 20 nm, further including means for cooperative permanent or temporary engagement with other biotechnology microfluidic devices selected from the group comprising a micro nozzle, a micro-nozzle with in-nozzle mixing effect, a micro flow restrictor, a micro aspiration tip, a micro dispenses tip, a reagent, a microsample delivery path, a cell aligner, a cell, protein or particle sorter.
  • It is an object of the present invention to form a tapered micro tube comprising a polymer, with internal circular cross section, the tapered microtube having an inner diameter that is smaller at one end increasing to larger at the other end, with the smaller end inner diameter measuring about 500 nm to about 500 um, the larger end inner diameter measuring about 50 um to about 10 mm, the larger end to smaller end inner diameter ratio about 5:1 to about 100: 1, forming a tapered microtube with inner surface roughness about 2 to 5 nm and having an inner surface roughness about 6 to 20 nm, wherein the tapered microtube is a component of a precision instrument.
  • a tapered micro tube comprising a polymer, with internal circular cross section, the tapered microtube having an inner diameter that is smaller at one end increasing to larger at the other end, with the smaller end inner diameter measuring about 500 nm to about 500 um, the larger end inner diameter measuring about 50 um to about 10 mm, the larger end to smaller end inner diameter ratio about 5:1 to about 100: 1, forming a tapered microtube with inner surface roughness about 2 to 5 nm and having an inner surface roughness about 6 to 20 nm, wherein the tapered microtube is a component of a precision instrument and incorporates at least one of the following components such as a micro nozzle, a micro nozzle with in-nozzle mixing effect, a micro flow restrictor, a micro aspiration tip, a micro dispense tip, and a micro cooling fluid, heating fluid, or lubrication fluid delivery path.
  • Figure 1 shows an oblique view of a hydrodynamic nozzle assembly
  • Figure 2 shows a sectional view of a hydrodynamic nozzle assembly of Figure 1;
  • Figure 3 shows an enlarged end view of a concentric extrusion formed by a hydrodynamic nozzle assembly as shown in Figure 1;
  • Figure 4 shows an embodiment of a machine system for forming extruded shapes with a hydrodynamic nozzle assembly as shown in Figure 1;
  • Figure 5 shows another embodiment of a machine system for forming extruded shapes with a hydrodynamic nozzle assembly as shown in Figure 1
  • Figure 6 shows yet another embodiment of a machine system for forming extruded shapes with a hydrodynamic nozzle assembly as shown in Figure 1;
  • F igure 7 shows a ferro system that may be utilized with a hydrodynamic nozzle assembly as shown in Figure 1 for forming any of the embodiments shown in Figures 4-7;
  • Figure 8 shows a control system used for controlling the machine system and hydrodynamic nozzle assembly as shown in Figure 1;.
  • Figure 9 shows a curved microtube formed with a hydrodynamic nozzle assembly as shown in Figure 1;
  • Figure 10 shows a photograph of a three-dimensional shape created with a hydrodynamic nozzle assembly as shown in Figure 1;
  • Figures 11A is a photograph showing a top view of cured polymer and internal core cavity, a cured sheath flow, and a core cavity drained of fluid having a 30 micron diameter formed with a hydrodynamic nozzle assembly;
  • Figures 1 IB is a photograph showing the change in diameter of the core fluid in the cured sheath formed with a hydrodynamic nozzle assembly
  • Figure 12a shows a side view of the hydrodynamic nozzle assembly and apparatus components including the funnel assembly, magnet assembly UV light assembly and substrate assembly;
  • Figure 12b shows a schematic showing the process modules for the hydrodynamic nozzle assembly and apparatus of Figure 12a;
  • Figure 13a shows a hydrodynamic nozzle assembly apparatus stage adjustment mechanism, inner nozzle, and funnel in fluid communication with the inner nozzle and the placement of the inner nozzle that deposits the core fluid (non UV -curable) into the sheath fluid;
  • Figure 13b is a schematic showing the stage adjustment mechanism for the hydrodynamic nozzle assembly apparatus of Figure 13 a;
  • Figure 14A shows a heated fdling hose for the sheath fluid and the core fluid and the holder for the outer funnel for the hydrodynamic nozzle assembly apparatus
  • Figure 14B shows a sectional view of the hydrodynamic nozzle assembly with the core fluid flowing into the sheath fluid stream, and the insert is fixed to the inner nozzle at a variable insertion distance, and the core stream maybe of similar or dissimilar in diameter, and the inner nozzle can be held stationary relative to the outer nozzle which can be rotated relative to the outer nozzle body, and be concentric with or eccentric relative to the outer nozzle;
  • Figure 15A is a shows the hydrodynamic nozzle assembly process apparatus including the motorize stage to adjust relative nozzle exit distance, the sheath fluid funnel, the core/sheath centering device, the UV curing lights (2x0, and the substrate or material bed on the xyz motor driven stages;
  • Figure 15B shows the hydrodynamic nozzle assembly with an additional insert that introduces two steams of core fluid into sheath fluid stream.
  • the insert is fixed to the inner nozzle at a variable insertion distance, and the two core streams maybe of similar or dissimilar in diameter, and the inner nozzle can be held stationary relative to the outer nozzle which can be rotated relative to the outer nozzle body, and ben be concentric with or eccentric relative to the outer nozzle;
  • Figure 16 shows the insulated heated hose for controlling viscosity of the core and sheath fluids for the hydrodynamic nozzle assembly
  • Figure 17 shows the digital control box that controls the heated hose temperature which then sets the desired viscosity of the sheath and core fluids for the hydrodynamic nozzle assembly
  • Figure 18 shows the pressurized pot delivering sheath fluid to the funnel, the temperature control system for the sheath and core fluids, and the insulation covering for the hydrodynamic nozzle assembly;
  • Figure 19 shows the insulated supply hoses for the core fluid (temperature controlled), and the syringe pump supplying the core fluid to the inside of the funnel of the hydrodynamic nozzle assembly;
  • Figure 20A shows a hydrodynamic nozzle assembly with core and sheath fluid supplied to the gravity fed assembly wherein the core fluid is fed into the sheath fluid flow and the coflowing core and sheath fluids flowing out of the exterior nozzle exit or a funnel wherein the sheath fluid is very viscous >50000 cP, while either fluid can be in a range of 1 cP up to 20,000 cP or greater;
  • Figure 20B shows the nozzles of the gravity fed assembly of Figure 20A, wherein the hydrodynamic nozzle assembly with two core fluid steams introduced into a fluid stream and blue core fluid within the clear liquid sheath fluid of Figure 20, wherein the diameter of the sheath fluid is the same as the nozzle at the exit and quickly necks down to about 1/10 of that within a short distance and continues to taper only slightly thereafter and the using this gravity focusing effect and curing the UV curable sheath fluid, hollow tubes with inner diameters as small as 200 nm have been created;
  • Figure 20C shows a sectional view of the core fluid flowing into the sheath fluid stream and the insert is fixed to the inner nozzle at a variable insertion distance, and the core stream may be of similar or dissimilar in diameter, and the inner nozzle can be held stationary relative to the outer nozzle which can be rotated relative to the outer nozzle body, and be concentric with or eccentric relative to the outer nozzle of the hydrodynamic nozzle assembly;
  • Figure 21 shows a sectional view of the hydrodynamic nozzle assembly with two core fluid steams introduced into a fluid stream and blue core fluid within the clear liquid sheath fluid of Figure 20, wherein the diameter of the sheath fluid is the same as the nozzle at the exit and quickly necks down to about 1/10 of that within a short distance and continues to taper only slightly thereafter and the using this gravity focusing effect and curing the UV curable sheath fluid, hollow tubes with inner diameters as small as 200 nm have been created;
  • Figure 22 shows the end of a coaxial tube having a inner core fluid and an outer sheath fluid formed from a hydrodynamic nozzle assembly
  • Figure 23 is an isometric view of Figure 22 showing the cylindrical core fluid and square sheath tube formed from a hydrodynamic nozzle assembly
  • Figure 24 is a plan side view of Figure 22 showing the square sheath tube formed from a hydrodynamic nozzle assembly
  • Figure 25 is a sectional view of Figure 22 showing the inner core fluid and outer sheath fluid tube and the elongated tip of the transition region formed from a hydrodynamic nozzle assembly;
  • Figure 26 is a photograph of the microfluidic tube showing the inner core fluid and outer sheath fluid forming smooth tapered core and sheath channel about 3 inches long having a 2mm diameter top section and 150 micron diameter bottom section formed by the gravity focusing process wherein the smooth tapered channel formed by a hydrodynamic nozzle assembly;
  • Figure 27 shows a photograph of the microfluidic tube having a 300 micron diameter channel that has a pathway the goes over and under itself in a 3D space, and surface roughness is from 2nm to 7nm SA (average surface roughness) formed by a hydrodynamic nozzle assembly;
  • Figure 28 is a photograph showing a cross section of a circular channel core of ferro fluid disposed within a bulk material gravity sheath formed by an extrusion and cured by UV radiation formed by a hydrodynamic nozzle assembly;
  • Figure 29 is a photograph showing a three dimensional pattern of a ferro fluid channel running throughout a gravity fed extrusion cured by UV radiation formed by a hydrodynamic nozzle assembly;
  • Figure 30 shows two channel cavities formed in cured solid, whereby the multiple streams of core fluid are injected into the sheath fluid to produce multiple cavities in the cured solid formed by a hydrodynamic nozzle assembly;
  • Figure 31 shows the shaping of core fluid diameter and sheath fluid cavity diameter using externally applied magnetic field to the microtubes formed by a hydrodynamic nozzle assembly
  • Figure 32 shows a tapered microtube product formed by the hydrodynamic nozzle assembly compared to a pen
  • Figure 33 shows a tapered microtube product and the wall thickness of the microtube formed by a hydrodynamic nozzle assembly
  • Figure 34 shows perspective view of a tapered microtube product formed inside of a rectangular block of polymer by a hydrodynamic nozzle assembly ;
  • Figure 35 shows a perspective view of a tapered microtube product of Figure 34, wherein broken lines illustrate the position of the tapered microtube formed within a rectangular block of a polymer.
  • sheath fluid is interchangeable with “focusing fluid”.
  • Hydrodynamic Focusing Apparatus and Method are interchangeable with “focusing fluid”.
  • the dimensions of the extrusions can be altered without the application of physical changes to the apparatus.
  • Figure 1 shows an oblique view of a hydrodynamic nozzle assembly 110. There is shown a first conduit 30 and a second conduit 40. There is also shown a concentric extrusion 50 formed by the hydrodynamic nozzle assembly 110.
  • Figure 2 is a section view of a hydrodynamic nozzle assembly 110.
  • a first conduit 30 supplies a sheath fluid to a sheath fluid channel 10.
  • a second conduit 40 supplies a core fluid to the core fluid channel 20.
  • the sheath fluid channel 10 splits into two channels near a top position, then merges to surround the core fluid channel 20 near a bottom position. This encourages laminar flow for both fluids as the fluids exit the channels.
  • Figure 3 shows an enlarged end view of a concentric extrusion 50 wherein the sheath fluid 25 surrounds the core fluid 15.
  • FIG. 4 shows an embodiment of a machine system 100 for forming extruded shapes.
  • a hydrodynamic nozzle assembly 110 supplied sheath fluid 15 (not shown) from a first conduit 30, and core fluid 25 (not shown) from a second conduit 40.
  • the hydrodynamic nozzle assembly 110 is configured in the machine system 100 to have an independent nozzle axis 115.
  • there are four degrees of freedom including x-, y-, and z- translation, and O rotation about the z-axis. Depending on the application, more or less degrees of freedom may be desired.
  • Extrusion 50 is normally flexible prior to curing.
  • Material bed 140 provides a surface for forming 2- dimensional (2D) and three-dimensional (3D) shapes.
  • a material bed axis 145 provides three- degrees of freedom for forming shapes from extrusion 50. These include x-, y-, and z- translation. Having two separate axes (115 and 145) enables greater flexibility in forming shapes from extrusion 50. We therefore describe motion as “relative motion” since both axes 115 and 145 may contribute.
  • a control system 200 provides control to all electrical systems of the machine system 100, which will be described in detail with reference to Figure 6.
  • Figure 4 also shows a curing system 120.
  • the curing system 120 is an ultraviolet (UV) system that is capable of rapidly curing a UV -responsive sheath material such as SR399 which is a dipentaerythritol pentaacrylate (DPHPA) available from Arkema S.A. in Colombes, France, or Arkema USA, LLC in Exton, Pennsylvania.
  • UV ultraviolet
  • SR399 which is a dipentaerythritol pentaacrylate
  • DPHPA dipentaerythritol pentaacrylate
  • the UV curing system 120 surrounds the extrusion 50 during curing to provide rapid and uniform curing.
  • One example of a UV surround system is to use reflectors to surround a single UV source. The reflectors may be positioned to redirect UV energy uniformly around the extrusion 50.
  • a UV ring light which normally consists of a series of UV LEDs positioned in a doughnut shape, may be used.
  • a UV ring light is a VisiLED UV ring light available from Schott ( yjy ,scho fco ).
  • a combination of UV lights may provide partial curing near the hydrodynamic nozzle assembly 110 by, for example, a UV ring light, and one or more additional UV lights directed to the final shape that may be positioned on a material bed 140.
  • Material bed 140 maybe metal, polymeric, glass, silicon wafer, or any suitable surface.
  • the material bed 140 may include threaded holes for attaching special fixtures which maybe used to make specific shapes.
  • One or more portions of material bed 140 may also be transparent or translucent to provide for additional UV lights to minimize any shadow areas, thereby enabling uniform UV curing of extrusion 50.
  • An extruded shape that is at least partially cured in situ maybe created in free space, wherein a shape may be extruded to make contact with the material bed 140 but then be moved away from the material bed 140 (in a y-direction), translated in an x- or z-direction in free space, then again making contact with the material bed 140.
  • Figure 5 shows an alternate embodiment of a machine system 100 for receiving extrusion 50 for forming shapes.
  • a mandrel 150 may receive extrusion 50.
  • the mandrel 150 is controlled by mandrel axis 155, which provides rotation about a central axis, and may also provide axial translation.
  • the mandrel maybe cylindrical, conical, or may include an offset axis for forming complex rotation-based shapes. Shown in Figure 5 is a conical shape that transitions to a cylindrical shape.
  • the mandrel may include holes or protrusions to anchor the leading end of the extrusion 50 prior to rotating. Coordination of themandrel axis 155 with the nozzle axis 115 is performed by the control system 200.
  • a curing system 120 may be used to cure extrusion 50.
  • the mandrel 150 may be at least partially transparent or translucent and fitted with UV lights to reduce shadow areas for uniform UV 30 curing.
  • the core fluid 25 used in the production of a concentric extrusion 50 requires removal.
  • the final shape maybe cured, trimmed if needed, and any core fluid 25 may be removed using manual methods. In other scenarios, however, auto-removal of the core fluid 25 may be preferred.
  • Figure 6 shows another alternate embodiment of a machine system 100 for receiving extrusion 50 for forming shapes.
  • material bed 140 includes a fluid removal system 160.
  • Fluid removal system 160 is comprised of at least one fluid port 170 that is exposed to the top surface (as shown) of the material bed 140.
  • a pressure system 180 enables positive or negative pressure to be applied. If more than one fluid port 170 is included, valves 190 enable pressure (positive or negative) to be applied only to the fluid port 170 that is in fluidic communication with the extrusion 50. By closing valves that are in fluid communication with any open fluid ports 170, pressure can be more efficiently directed to the extrusion 50. For some extrusions 50 that are extremely flexible, it may be preferred to at least partially cure the extrusion 50 prior to removing the core fluid 25 to avoid inflating (if positive pressure is used) or collapsing (if negative pressure is used) the extrusion 50.
  • the leading end of the extrusion 50 is placed in fluid communication with a fluid port 170 prior to shape formation. Curing or partial curing may occur during extrusion.
  • pressure maybe applied using the pressure system 130. It is preferred that the severed end of the extrusion 50 be at least partially opened during application of pressure.
  • a ferro system 192 is shown in simplified form, which may be used in cooperation with a magneto rheological or other responsive fluid such as an electro rheological fluid hereinafter “smart fluid” as the core fluid 25.
  • the ferro system 192 maybe a permanent magnet or electro-magnet that is capable of shaping the extrusion 50 by changing its position or cross-section acting on the ferro fluid as the core fluid 25.
  • the ferro system 192 is controlled by ferro axis 195, which may provide rotation and translation of the ferro system 192.
  • the apparent viscosity can be changed by the application of a magnetic or electric field, creating a flow change and therefore shape change in the core fluid.
  • Combining and diverging the core streams allow for a wide range of shape adjustments to the extruded shape.
  • the control system 200 is supplied power by a power supply 280.
  • the control system 200 may include a communication interface or module 220 coupled to a shape processing module 230.
  • the shape processing module 230 may be communicatively coupled to an extrusion module 240, a positioning module, 250, a curing module 260, a pressure module 270, and a ferro module 275.
  • the shape source 210 may be any type of device capable of transmitting data related to a shape file to be formed by machine system 100 in cooperation with the shape processing module 230.
  • the shape source 210 may include a general-purpose computing device, e.g., a desktop computing device, a laptop computing device, a mobile computing device, a personal digital assistant, a cellular phone, etc. or it may be a removable storage device, e.g., a flash memory data storage device, designed to store data such as shape data.
  • the communication interface 220 may include a port, e.g., a USB port, to engage and communicatively receive the storage device.
  • the communication interface 220 may include a wireless transceiver to allow for the wireless communication of shape data 215 between the shape source 210 and the control system 200.
  • the communication interface 220 may facilitate creation of an infrared (IR) communication link, a radio-frequency (RF) communication link or any other known or contemplated communication system, method or medium.
  • IR infrared
  • RF radio-frequency
  • the communication interface 220 may be configured to communicate with the shape source 210 through one or more wired and/or wireless networks.
  • the networks may include, for example, a personal area network (PAN), a local area network (LAN), a wireless local area network (WLAN), a wide area network (WAN), etc.
  • PAN personal area network
  • LAN local area network
  • WLAN wireless local area network
  • WAN wide area network
  • the networks may be established in accordance with any number of standards and/or specifications such as, for example, IEEE 802.1 lx (where x indicates a, b, g and n, etc.), 802.16, 802.15.4, Bluetooth, Global System for Mobile Communications (GSM), code-division multiple access (CDMA), Ethernet, etc.
  • GSM Global System for Mobile Communications
  • CDMA code-division multiple access
  • the shape processing module 230 may receive the shape data 215 from the communication interface 220 and process the received shape data 215 to create a shape j ob 225 for use within the machine system 100. Alternatively, the processing of the shape data 215 may be performed by the shape source 210 or other device or module and the resulting shape job 225 maybe communicated to the communication interface 220. The processed shape data 215 and/or shape job 225 may, in turn, be provided to the shape processing module 230. The shape processing module 230 can cache or store the processed shape data215 or may communicate the shape data 215 in real-time for shape job 225 creation.
  • the shape processing module 230 sends the shape job 225 to the extrusion module 240, positioning module 250, curing module 260, and optionally the pressure module 270 if using a pressure system 180 with the material bed 140, and optionally the ferro module 275 ifferro fluid is used as the core fluid 25 .
  • the extrusion module 240 controls the extrusion parameters based on material properties of the sheath fluid 15 and core fluid 25, and desired shape outcome.
  • the extrusion module 240 is configured to cooperate with positioning module 250, which includes positioning data for the nozzle axis 115 and material bed axis 145.
  • the positioning module 250 includes positioning data for the nozzle axis 115 and mandrel axis 155.
  • Position sensors 290 provide feedback for closed-loop location information.
  • Sample position sensors 290 include optical encoders (not shown) that may be linear or rotary strips having scale markings that are detected by optical sensors. An analog or digital signal may provide position feedback based on the number of scale markings detected by the optical sensors.
  • Pressure module 270 receives information from the shape processing module 230 whethercore fluid 25 will be removed by pressure or not.
  • the magnitude and direction of pressure (such as low vacuum pressure or moderate positive pressure) will be determined based on the anticipated properties of the extrusion 50 at the time pressure is to be applied.
  • the pressure module 270 will also control any valves 190 ifmultiple fluid ports are available for use. If there is only one fluid port, there is no need forvalves 190.
  • the apparatus components of the invention include a hydrodynamic nozzle assembly 110, ferro system 192, curing system 120, and material bed 140. More particularly, the hydrodynamic nozzle assembly 110 includes an outer nozzle assembly 105 containing the sheath fluid 25 with an inner nozzle assembly 103 that delivers the core fluid 15, as shown in Figures 13 and 14. Both fluids then exit the outer nozzle exit 108 together and both fluids are reduced in diameter due to the gravity focusing effect. Permanent magnets are used (it is anticipated electromagnets in the ferro system 192 can be used as well) when a ferro-fluid is the core fluid 15 to change the shape of the inner tube diameter.
  • An effective amount of curing radiation from UV curing lights have 405 nm wavelength to cure the falling sheath fluid is use as the curing system 120 for the duration necessary. Light sources of other wavelengths are anticipated for alternative sheath fluids 25.
  • the material bed 140 is position controlled by material bed axis 145 (xyz stage motion) to catch the cured CO-flow extrusion 50 and/or allow build up and different channel patterns (3D).
  • Figures 13 and 14 show the inner nozzle assembly 103 and outer nozzle assembly 105 collectively hydrodynamic nozzle assembly 110 with dependent nozzle axis 113 and independent nozzle axis 115. Moreover, the dependent nozzle axis 113 adjust the position of the inner nozzle exit 107 to the outer nozzle exit 108.
  • the inner nozzle assembly 103 deposits the core fluid 15 into the sheath fluid 25 flow. The distance between the inner nozzle exit 107 and the outer nozzle exit 108 is a key factor in determining the interaction of the core fluid 15 and sheath fluid 25 to create the fluid focusing effect.
  • the stage adjustment mechanism, inner nozzle, and funnel in fluid communication with the inner nozzle. Moreover, the stage adjusts the distance from the inner nozzle exit to the outer nozzle exit.
  • the inner nozzle deposits the core fluid into the stream flow. It is important that the distance between the exit end of the nozzle is at the correct distance from the exit of the funnel nozzle.
  • the funnel contains the sheath fluid (UV curable).
  • the drawing shows the placement of the inner nozzle that deposits the core fluid (nonOuv curable) into the sheath fluid.
  • Figure 13a and 13b also shows how the stage 104 adjusts the distance from the inner nozzle exit to the outer nozzle exit.
  • the inner nozzle that deposits the core fluid is a key parameter and controls the distance of the inner nozzle to the exit of the funnel outer nozzle.
  • the funnel 24 containing the sheath fluid 25 (UV curable) is shown that the placement of the inner nozzle that deposits the core fluid 15 (non-UV curable fluid into the sheath fluid 25.
  • Temperature controlled first sheath conduit 30 and second core conduit 40 deliver the sheath fluid 25 and core fluid 15 respectively from sheath fluid supply 125 and core fluid 130 to the hydrodynamic nozzle assembly 110. Viscosity of the fluids is lowered by heating and increased by cooling.
  • Figure 14A shows the heated filling hoses for the sheath fluid and core fluid. The higher the viscosity the longer the manufactured tube body. The lower the viscosity, the less bubbles are produced in the tube body.
  • the holder 204 provides adjustment of the dependent nozzle axis 113 and can also be used to locate the center of the core fluid 15 relative to the center of the sheath fluid 25 so the inner and outer diameters of the manufactured tube will be concentric or eccentric with respect to each other.
  • the funnel contains the sheath fluid 25 with a nozzle on the inside that delivers the core fluid 15. Both fluids then exit the nozzle of the funnel together coaxially and both fluids are reduced in diameter due to the gravity focusing effect.
  • Permanent magnet used when one uses a ferro fluid as the core fluid is greater when use do change the shape of the inner tube diameter.
  • UV curing light with 405nm wavelength can be used to cure the falling sheath fluid 25 in one preferred embodiment.
  • a material bed such as a substrate mounted onto a movable drive (xyz stage motion) to catch the cured stream and/or to allow build up and a different channel to create patterns.
  • the dimensions of the extrusions can be altered without the application of physical changes to the apparatus.
  • Figure 14A shows the heated filling hose for the sheath fluid and the core fluid and 14B shows details of the hydrodynamic nozzle assembly 110.
  • Heating the core and sheath tube conduits controls the viscosity of the fluids. The higher the viscosity the longer the manufactured tubes. The lower the viscosity, the less bubbles that result in the manufactured tube body.
  • the holder for the outer funnel It is adjustable in the x and y directions so as to make sure the inner nozzle is perfectly centered in the outer funnel nozzle. That way the core fluid 15 stream is centered in the sheath fluid 25 stream such that the inner and outer diameters of the manufactured tubes are concentric.
  • Figure 14A also shows a heated filling hose 202 for the core fluid and heated core filling hose 203. Hating the hose controls the viscosity of the fluids. Higher viscosity forms longer manufactured tubes. Lowering the viscosity decreases the amount of bubbles that could form in the tube body.
  • the holder 204 is shown holding the outer funnel 24. It is adjustable in the x and y directions so as to make sure the inner nozzle is perfectly centered in the outer funnel nozzle so the core stream is centered in the sheath stream to form concentric inner and outer diameters of the tubes.
  • Figure 15A shows the process apparatus including the motorized stage 104 to adjust relative nozzle exit distance, the sheath fluid funnel 24, the core/sheath centering device 204, the UV curing lights (2x0) 120, and the substrate or material bed 140 on the xyz motor driven stages;
  • the heated filling hose for the sheath fluid and the core fluid and the holder for the outer funnel Heating the hose controls the viscosity of the fluids. The higher the viscosity the longer the manufactured tube body. The lower the viscosity, the less bubbles are produced in the tube body.
  • the holder for the outer funnel is adjustable in the x and y directions so as to make sure the inner nozzle is perfectly centered in the outer funnel nozzle so that the core stream is centered in the sheath steam such that the inner and outer diameters of the manufactured tube are concentric as shown in Figure 14.
  • Figure 15 is an perspective view of the assembly showing the motorized stage to adjust relative to the nozzle exit distance, sheath fluid funnel, core/sheath fluid centering device, UV curing lights (2x), and substrate on xyz motor driven stages.
  • Figure 15B shows an alternate assembly with additional insert that introduces two steams of core fluid 15A and 15B into sheath fluid stream.
  • the insert is fixed to the inner nozzle at a variable insertion distance, and the two core streams may be of similar or dissimilar in diameter, and the inner nozzle exit 107 can be held stationary relative to the outer nozzle 108 which can be rotated relative to the outer nozzle body 109 and be concentric with or eccentric relative to the outer nozzle 108.
  • Figure 16 shows the insulated heated hose 203 for controlling viscosity of the core and sheath fluids.
  • Figure 17 shows the digital control box 220 that controls the heated hose temperature which then sets the desired viscosity of the sheath and core fluids.
  • Figure 18 shows the pressurized pot 219 for delivering sheath fluid to the funnel, the temperature control system for the sheath and core fluids, and the insulation covering.
  • Figure 19 shows the insulated supply hoses for the core fluid (temperature controlled), and the syringe pump 221 supplying the core fluid to the inside of the funnel.
  • the digital control box that controls the heated hose temperature which then sets the desired viscosity of the sheath and core fluids.
  • the pressurized pot delivering sheath fluid to the funnel, and showing the temperature control system for the sheath and core fluids to control the viscosity, and the insulation covering the heating element and the delivery hose for the core/sheath fluids as shown in Figure 18.
  • Figure 20A shows a hydrodynamic nozzle assembly 1 10 with core 15 and sheath fluid 25 supplied to the gravity fed assembly wherein the core fluid 15 is fed into the sheath fluid flow and the coaxial core and sheath fluids 37 co-flowing out of the exterior nozzle exit 108 or a funnel wherein the sheath fluid is very viscous >50000 cP, while either fluid can be in a range of 1 cP up to 20,000 cP or greater.
  • Figure 20B and 20C show the nozzle of the gravity fed assembly of Figure 20A and view of the co-flowing tapered coaxial core and sheath fluid 37 exiting the nozzle.
  • the hydrodynamic nozzle assembly 110 has a core fluid steam 15 introduced into a clear sheath fluid stream 25 wherein the blue core fluid 15 is surrounded by the clear liquid sheath fluid 25.
  • the diameter of the sheath fluid 25 is the same as the nozzle at the nozzle exit 108 and quickly necks down to about 1/10 of that within a short distance and both the core fluid 15 and coaxial sheath fluid 25 continue to taper only slightly thereafter and the using this gravity focusing effect and curing the UV curable sheath fluid, hollow tubes with inner diameters as small as 200 nm have been created.
  • An extruded shape in the form of an “S” is desired which is shown in Figure 8.
  • the “S” is 40 mm in height, and 27 mm in width.
  • the thickness (outer diameter of the extrusion) is 1 mm (1 ,000 microns).
  • the sheath fluid 15 used is a polyacrylate.
  • the core fluid is water.
  • the inner diameter of the sheath fluid is 0.5 mm (500 microns).
  • the shape will be trimmed manually after curing. Since water is used as a core fluid, and the inner diameter of the shape is sufficiently large so that capillary retention of the core fluid should be minimal, the automated pressure module 270 will not be requested.
  • the sheath fluid 15 is capable of being partially cured using typical curing wavelengths.
  • the curing system 120 is a 35-watt UV LED light ring attached to the hydrodynamic nozzle assembly 110.
  • the material bed 140 includes a top surface of transparent glass. Belowthe material bed 140 is a 35- watt UV LED array.
  • the extruded shape was drawn and converted to a vector file, which is the shape data 215.
  • the shape data 215 was received by the communication interface 220 and sent to the shape processing module 230 for processing into a shape job 225.
  • the shape job 225 was sentto the extrusion module 240, the positioning module 250, and the curing module 260.
  • the machine system 100 was then activated, the hydrodynamic nozzle assembly 110 was preheated to 100 °F (37.8 °C), and sheath fluid 15 and core fluid 25 were introduced to the hydrodynamic nozzle assembly 110 via first conduit 30 and second conduit 40, respectively.
  • the hydrodynamic nozzle assembly 1 10 moved to a close proximity (within 25 mm) to the material bed 140, which is planar. Extrusion from the hydrodynamic nozzle assembly 1 10 was activated, and the nozzle axis 1 15 and material bed axis cooperated to produce relative motion between the hydrodynamic nozzle assembly 110 and the material bed 140 that resulted in an “S” shape being extruded onto the material bed 140.
  • the hydrodynamic nozzle assembly 110 was moved to a central position above the shape, andthe curing system 120 was activated. Both the UV LED light ring and the UV LED array were activated simultaneously for 12 seconds ( 10 seconds minimum and a safety margin of 2 seconds). After 12 seconds, the curing system 120 was deactivated, and the hydrodynamic nozzle assembly 110 and the material bed 140 were returned to a home position, enabling the user to manually remove the shape for trimming and removal of the core fluid 25.
  • the sheath fluid 15 used was a polyacrylate.
  • the core fluid was water.
  • the inner diameter of the sheath fluid was 0.03 mm (30 microns).
  • a random three-dimensional shape was created as shown in Figure 10.
  • the sheath fluid 15 used was a dipentaerythritol pentaacrylate.
  • the core fluid was an electro rheological fluid EMG 700 from Ferrotec USA Corporation, located in Santa Clara, California.
  • the inner diameter of the sheath fluid was 0.03 mm (30 microns).
  • a random three- dimensional shape was created according to aspects of the present disclosure. See Figures 1 la and 1 lb.
  • This method uses co-flow of two immiscible fluids that exit a nozzle, chute, ledge, beaker edge or the like (all termed “nozzle”), simultaneously, and one totally encased by the other, but not necessarily at the same flow rates.
  • the motive force for the co-flowing fluids from the “nozzle” may be gravity, centrifugal force or any other body force generation method.
  • the outer fluid is termed the sheath fluid and the inner fluid is termed the core fluid.
  • a distinguishing characteristic of the flow from the “nozzle” is that the diameter or width of sheath fluid is reduced as it exits the “nozzle”.
  • the core fluid likewise, is reduced in width or diameter.
  • Gravity focusing is distinguished from the commonly used method of hydrodynamic focusing in that, hydrodynamic focusing generates co-flow from a nozzle into a constrained channel, whereas gravity focusing generates co-flow from a nozzle into unconstrained free space.
  • hydrodynamic focusing relies on surface forces (like applied pressure) to force the sheath and core fluids through converging nozzles to provide focusing
  • gravity focusing relies upon the body force of gravity, the initial geometry of the nozzle, the sheath and core viscosities and the surface tension between the nozzle and sheath fluid at the exit to provide focusing.
  • the flow of material for a gravity focusing system is characterized by the jet shape and depends on the dynamic viscosity of the Newtonian fluid typically forming a concave jet, flow velocity at the nozzle resulting in a straight, vertical shape, falling height forming a vertical jet, and the flow of material application onto a moving substrate whereby the flow of material forms a convex shape.
  • This method further relies on the sheath fluid being comprised of a fast curing, liquid plastic that can be cured by different means but preferentially using ultra-violet light, and the core fluid being non- curable, but immiscible with the sheath fluid, so as the core and sheath fluid remain co-flowing and do not mix as the co-flowing jet travels away from the nozzle exit.
  • the fast curing UV lights are positioned some distance below the nozzle exit and some distance away from the co-flowing sheath and core fluids. The exact distances depend upon the tubular geometry desired. As the co-flowing fluid stream passes between the UV lights they are activated such that the sheath fluid is cured into a solid plastic material.
  • That material is then removed either as a discrete part or spooled onto a mandrel in a continuous fashion, depending upon the tube design objectives.
  • the core fluid may remain inside the tube, may be cleaned out of the tube or replaced by another material inside the tube depending upon the design and use intent.
  • This method has advantages over other tube making methods in that it can be used to focus the core material into very small diameters (as small as 200nm have been achieved). It can be used to make tubes with core materials of larger diameters, limited only by the nozzle design. Microtubes at least up to 2mm have been achieved and the tubes can be made with tapered core diameters. Furthermore a plurality of microtubes can be bundled for higher flow rate and/or surface area or flow rate.
  • the resulting inner diameter of the tube has a superior surface as compared to polished, drawn, traditional micro machined, injection molding, extruding and other methods (1-5 nm Ra which is a mirror finish) because the process essentially molds the sheath fluid around a core fluid and the core fluid has a very smooth surface roughness (molded parts take on the surface roughness of the molds used to make them).
  • the tubes can be further processed into microfluidic chips (2D networks of channels) and microfluidic bricks (3D networks of channels) by molding the tubes into a larger matrix of the UV curable material.
  • a 100 mL beaker with approximately 25 mL of highly viscous, UV curable sheath material and 5 mL of significantly less viscous core material was used where the core material specific gravity is greater than that of the sheath material such that it remains inside the sheath material as a ball of material (doesn’t float to the top and spread out).
  • the beaker was simply tilted by hand such that the sheath material began to flow over the edge of the spout and the flow of the sheath material began to draw from the ball of the core material until a small stream of the core material formed on the inside of the sheath material, both materials co-flowing over the edge of the beaker.
  • a hand-held radiation device such as a UV light, was used to cure the sheath material just prior to it collecting onto a substrate such as a material bed, resulting in solid diameters of plastic tubing with micro sized inner diameters.
  • the plastic tubing was then cast into a larger chip of UV cured material and the inner channels were accessed by drilling and then gluing connectors in place. In this manner a microfluidic flow chip of 3D nature was created.
  • a funnel nozzle or an L-shaped chute can be utilized as the nozzle.
  • the sheath fluid is maintained in the funnel or chute using a syringe pump or a pressurized pot with a hose.
  • the core fluid is injected into the sheath fluid using a syringe pump with a syringe and a dispense tip or syringe needle depending upon the design intent.
  • UV curing lamps under automatic control are actuated to cure the material.
  • the material either collects onto a substrate plate or is captured in free space and removed as a discrete tubular section.
  • a mandrel is not yet implemented but can be used to collect the tubular section in a continuous fashion to create very long tubes of several feet in length and the length is only limited by the length of the mandrel.
  • Figure 21 shows a gravity fed assembly nozzle of Figure 20C in cross section with two core streams.
  • Figures 20 and 21 shows a photograph gravity fed assembly having a blue core fluid within a clear liquid sheath fluid extending from the funnel.
  • the sheath fluid id very viscous greater than 5000 centipoise.
  • Either fluid can be in a range of IcP (like water) up to 20,000 centipoise or greater (2-3 times the viscosity of honey).
  • the gravity focusing effect is seen for both fluids as the diameter of the sheath fluid is that of the nozzle at the exit and it quickly necks down to about 1/20 of that within a small distance.
  • the fluid continues to taper but only slightly at distances away from the nozzle. Using this gravity focusing effect and curing the UV curable sheath fluid, hollow tubes have been formed with inner diameters as small as 200 nanometers.
  • Figure 22 shows the end of a coaxial tube formed in a block having a inner core fluid and an outer sheath fluid
  • Figure 23 is an isometric view of Figure 22 showing the cylindrical core fluid and square sheath tube
  • Figure 24 is a plan side view of Figure 22 showing the square sheath tube
  • Figure 25 is a sectional view of Figure 22 showing the inner core fluid and outer sheath fluid tube and the elongated tip of the transition region.
  • FIG. 26 is a microfluidic tube having a smooth tapered channel with a 2mm diameter to section and a 150 micron diameter bottom section about 3 inches long produced by a gravity focusing process.
  • a microfluidic tube having a smooth tapered channel with a 300 micron diameter channel that has a pathway the gods over and under itself in a 3D space ( 10mm x 10mm x 70mm) produced by a gravity focusing process is shown in Figure 27.
  • Minimum tapered diameters are about 200 nm and maximum tapered diameters are about 3mm.
  • Surface roughness range measured for the channel surfaces range from 2nm to 7 nm Sa (average surface roughness).
  • Fluids streams are acted upon using other process manipulations, as well as externally applied forces (including, but not limited to, magnetic, acoustic, mechanical vibration, and mechanically induces deflection) to produce defined features and shaping of the cavities in the cured solid.
  • Figure 30 shows two channel cavities formed in cured solid, whereby the multiple streams of core fluid are injected into the sheath fluid to produce multiple cavities in the cured solid.
  • Figure 31 shows the shaping of cavity diameter using externally applied magnetic field.
  • the experimental embodiment described in the examples is flexible and the apparatus is altered to provide various product configurations, including at least one or more of the following steps of: a) One core fluid stream feeds into the sheath fluid stream; b) Multiple core fluid streams feed into a sheath fluid stream; c) Collection of core fluid streams are rotated during feed into sheath stream and curing process; d) Core fluid stream feeds into a fluid stream that feeds into a third, outer fluid stream; e) UV curing in area of maximum flow focus to produce funnel-like shapes; f) UV curing further removed from mechanical outlet for more constant diameter tubing; g) Flat substrate to capture shorter length extrusions; h) Spool to capture longer length extrusions;

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Abstract

Un procédé de formation de dispositifs microtubes extrudés et de produits ayant une partie creuse utilisant une buse hydrodynamique, un fluide durcissable et un fluide central pour former des microtubes à base de polymère flexible ayant un diamètre interne allant de 500 nanomètres à 500 micromètres et également des microtubes continus ayant un diamètre interne variable allant d'environ 500 nanomètres à 500 micromètres. Le diamètre externe peut être variable et avoir une forme de section transversale qui est circulaire, rectangulaire, carrée, triangulaire, elliptique, en étoile, irrégulière, incurvée ou formée à l'intérieur d'un bloc solide de matériau.
PCT/US2023/018739 2022-04-14 2023-04-14 Procédé hydrodynamique et de gravité de formation et de mise en forme de dispositifs microfluidiques coniques WO2023201093A1 (fr)

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US17/960,120 US20230249965A1 (en) 2021-07-20 2022-10-04 Hydrodynamic and gravity focusing apparatus and method of forming and shaping microfluidic devices
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