METHOD FOR MAKING A BODY WITH ARRANGED PARTICLES USING ACOUSTIC WAVES

Abstract

The present disclosure relates to a method for manufacturing a body comprising a particle structure fixated in a matrix material, said method comprising the steps of: providing a mixture of a viscous matrix material and particles, subjecting said particles to an acoustic standing wave, so as to arrange at least portion of said particles in a pressure node and/or a pressure antinode of the acoustic standing wave thereby creating a particle structure In said viscous matrix material and fixating said viscous matrix material so as to fixate said particle structure In said matrix material. The disclosure also relates to a body obtained by said method, and to the use of said method in various applications.

Claims

1. A method for manufacturing a film comprising a particle structure fixated in a matrix material, the method comprising the steps of: providing a mixture of a viscous matrix material and particles; subjecting the particles to an acoustic standing wave, so as to arrange at least a portion of the particles in at least one of the group consisting of a pressure node and a pressure antinode of the acoustic standing wave thereby creating a particle structure in the viscous matrix; and fixating the viscous matrix so as to fixate the particle structure in the matrix material.

2. The method of claim 1, further comprising the step of contacting the mixture with a first support and a second support.

3. The method of claim 2, wherein a pressure node is formed at an interface between the mixture and at least one of the group consisting of the first support and a pressure node is formed within the mixture.

4. The method of claim 2, wherein a pressure antinode is formed at an interface between the mixture and at least one of the group consisting of the first support and a pressure antinode is formed within the mixture.

5. The method of claim 2, further comprising a step of removal of at least one of the group consisting of the first support and the second support.

6. The method of claim 5, wherein the removal involves exposure of at least part of the particle structure.

7. The method of claim 1, wherein the body has the shape of a film with width: 0.01-100 m, thickness: 0.01-10 mm, length: 0.0001-100 km.

8. The method of claim 1, wherein the particles are selected from at least one of a group consisting of metal particles, air bubbles, oil droplets, polymer particles, carbonaceous particles, ceramic particles, bioactive particles, bacteria, viruses, archaea, fungi, sand particles, glass particles, and colloidal particles.

9. The method of claim 1, wherein the particles have substantially the same size.

10. The method of claim 1, wherein the viscous matrix material comprises or consists of a polymer.

11. The method of claim 1, wherein the viscous matrix is fixated by curing.

12. The method of claim 1, wherein the particle assemblies are further subjected to at least one of the group consisting of an electric field and a magnetic field.

13. The method of claim 1, wherein the method is used in combination with at least one of a group consisting of roll-to-roll processing, extrusion processes, 3D printing, electric and magnetic fields, optical trapping and manipulation, and printed electronics technology.

14. A body comprising a particle structure fixated in a matrix material, wherein the body is obtainable according to claim 1.

15. An article comprising or consisting of a body according to claim 13, the article being selected from at least one of a group consisting of packaging materials, printed electronics, laminated materials, textiles, paper, and containers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The disclosure will now be further illustrated with reference to exemplary embodiments, with reference to the enclosed drawings, wherein:

[0055] FIG. 1 shows a structure comprising a first support 1 and a second support 2 between which a mixture of particles 3 and a viscous matrix material 4 is located.

[0056] FIG. 2 shows the structure of FIG. 1 subjected to an acoustic standing wave providing nodes 5 and antinodes 6. The particles gather in the nodes 5 and antinodes 6.

[0057] FIG. 3a shows the structure of FIG. 1 after having been subjected to an acoustic wave in such a way that the particles are pushed to a surface of the film being produced.

[0058] FIG. 3b shows the structure of FIG. 3a after fixating of the viscous matrix material followed by removal of the first support 1.

[0059] FIG. 4 shows the structure of FIG. 1 after having been subjected to an acoustic standing wave in such a way that the particles are pushed to a mid-point of the film being produced, followed by fixating of the viscous matrix material 4 and removal of the first support 1.

[0060] FIG. 5 shows production of new materials, such as tapes or films.

[0061] FIG. 6 shows how the process images are taken.

[0062] FIG. 7 shows AFS process in a glass plate flow cell with a fluid channel in between.

[0063] FIGS. 8a,b,c shows the AFS process used on micro organisms.

[0064] FIG. 8a: F=0 Hz

[0065] FIG. 8b: F=1950 kHz

[0066] FIG. 8c: F=5770 kHz

[0067] FIG. 9: 4.5 m polystyrene beads low concentration when applying the acoustic force.

[0068] FIG. 9A: Applied AF, 2 nodes

[0069] FIG. 9B: Particles clustering

[0070] FIG. 9C: Frequency change moves particles to new plane.

[0071] FIG. 10: Increased concentration by 100 fold with 4.5 m beads.

[0072] FIG. 11: A sweep over a large range of frequencies that is applied.

[0073] FIG. 11A: Force off (T=0)

[0074] FIG. 11B: Force on (T=1)

[0075] FIG. 11C: Force on (T=2)

[0076] FIG. 11D: Force on (T=3)

[0077] FIG. 12: Acoustic affects with smaller 2.1 m polystyrene beads.

[0078] FIG. 13: When the force is turned on kaolin is pushed on the acoustic node and overtime the Kaolin clusters together.

[0079] FIG. 13A: Force off

[0080] FIG. 13B: Force on

[0081] FIG. 14: The effect on the viscosity was studied by measuring the velocity of the bead when responding to acoustic force.

[0082] FIG. 15: Measured force response when viscosity is increased: 0, 10, 20 and 30% of glycerol was used to increase the viscosity and measure the effect on the force amplitude.

[0083] It should be noted that the drawings have not been drawn to scale and that the dimensions of certain features have been exaggerated for the sake of clarity.

DEFINITIONS

[0084] Nanometer is abbreviated nm.

[0085] Micrometer is abbreviated m.

[0086] Node is used interchangeably with pressure node.

[0087] Antinode is used interchangeably with pressure antinode.

[0088] AFS is used as abbreviation for acoustophoresis.

DETAILED DESCRIPTION OF EMBODIMENTS

[0089] The device for preparing an anisotropic and/or inhomogeneous polymer film using an acoustic wave may be referred to as an acoustic force applicator (piezo). The acoustic is force applicator may be utilized for this method in a continuous process. In one or more embodiments, a continuous process may include a roll to roll process, where a roll of polymer film is provided, the polymer film is unrolled and moved through the acoustic field application zone to induce orientation in the polymer film, and rerolled on a take-up roll down line from the acoustic field application zone. In some embodiments, a continuous process may be provided where the polymer film is prepared, for example by polymer film casting on one end of the acoustic field generator, the polymer film is then moved through the acoustic field application zone to induce structures in the polymer film, and rolled on take-up roll down line from the acoustic field application zone.

[0090] Suitable polymers that may be used to create anisotropic polymer films include UV curable polymers, thermally curable polymers, and polymers in solution. The polymers may be heteropolymers or copolymers.

[0091] In one or more embodiments, the polymer film may include a block copolymer. In one or embodiments, the block copolymer may be a di-block copolymer represented by the formula: A-B, where A represents a block of repeating units and B represents a second different block of repeating units. In one or embodiments, the block copolymer may be a tri-block copolymer represented by the formula: A-B-A or A-B-C, where A represents a block of repeating units, B represents a second different block of repeating units, and C represents a third different block of repeating units. In one or embodiments, the block copolymer may be a tetra-block copolymer represented by the formula: A-B-A-B, A-B-C-A, A-B-C-B, or A-B-C-D, where A represents a block of repeating units, B represents a second different block of repeating units, and C represents a third different block of repeating units, and D represents a fourth different block of repeating units.

[0092] In embodiment that use a polymer in solution useful solvents for dissolving the polymer include, N-methyl pyrrolidine (NMP), dimethylformamide (DMF). dimethylsulfide (DMS), dimethylsulfoxide (DMSO), dimethyl acetamide (DMAC), cyclohexane, pentane, cyclohexanone, acetone, methylene chloride, carbon to tetrachloride, ethylene dichloride, chloroform, ethanol, isopropyl alcohol (IPA), butanols, THF, MEK, MIBK, toluene, heptane, hexane, 1-pentanol, water, or suitable mixtures of two or more thereof. The solvents can be both aqueous or non-aqueous.

[0093] In one or more embodiments, the concentration of polymer in solvent in the polymer solution is from about 5 weight percent to about 50 weight percent, in other embodiments from about 10 weight percent to about 45 weight percent, in other embodiments from about 15 weight percent to about 40 weight percent, in other embodiments from about 20 weight percent to about 35 weight percent, in still other embodiments from about 25 weight percent to about 30 weight percent.

[0094] As noted above, the polymer film may include particles. Suitable particle for use in preparing anisotropic polymer films include conducting particles semiconducting particles or dielectric particles. It should be noted, that in certain embodiment, particularly where a semi-conducting or conducting particle is used, an insulating layer may be required between the polymer film and the electrodes.

[0095] Suitable conductive particles may be prepared from Co, Ni, CoPt, FePt, FeCo. Fe3O4, Fe2O3, and CoFe2O4. Suitable semiconductive particles may be prepared from ZnS, CdSe, CdS, CdTe, ZnO, Si, Go, GaN, GaP, GaAS, InP, and InAs. Additional particles that may be conductive or semiconductive include carbon based nanoparticles, carbon black, carbon nanotubes (single as well as multi-walled) as well as other inorganic and organic synthetic or natural nanoparticles.

[0096] In some of the various embodiments, the size of the particles are in the range of about 0.1 nm to about 500 micrometres. In some of the various embodiments, the body has the shape of a film with width in the range of: 0.01-100 m, preferably 0.1 to 10 m, thickness 0.01-10 mm, preferable 0.1 to 1 mm and length: 0.0001-100 km, preferable above 1 m. In a roll to roll production of film, the film could be continuous and as such have an indefinite length.

[0097] The embodiments are further illustrated by the figures discussed below:

[0098] FIG. 1 shows a structure comprising first support 1 and a second support 2 between which a mixture of particles 3 and a viscous matrix material 4 is located. The particles comprise substantially spherical particles and elongate particles. The first support 1, the second support 2, the particles 3 and the viscous matrix material 4 may be as described elsewhere in this document. The structure has not yet been subjected to an acoustic standing wave, and it can be seen that the particles are randomly distributed within the viscous matrix material.

[0099] FIG. 2 shows the structure of FIG. 1 subjected to an acoustic standing wave providing nodes 5 and antinodes 6. The spherical particles gather in the nodes 5. The elongate particles gather in the antinodes. This illustrates the fact that the particles with different properties, such as different shapes, will be differently affected by the acoustic wave and therefore move to different locations.

[0100] FIG. 3a shows the structure of FIG. 1 after having been subjected to an acoustic wave in such a way that the particles are pushed to a surface of the film being produced.

[0101] FIG. 3b shows the structure of FIG. 3a after fixating of the viscous matrix material followed by removal of the first support 1. As can be seen, removal of the first support leads to exposure of the particles 3.

[0102] FIG. 4 shows the structure of FIG. 1 after having been subjected to an acoustic standing wave in such a way that the particles are pushed to a mid-point of the film being produced, followed by fixating of the viscous material 4 and removal of the first support 1. As can be seen, in this case removal of the first support does not expose the particles 1.

[0103] FIG. 5 shows how the wanted material out pushed in the acoustic node to make industrial tapes or films A mixture of particles and curable solvent are guided to a piezo device that is in contact with the film. The piezo applies the acoustic wave (AFS) that positions the particles in the mixture in the acoustic node. This is followed by a curing stage (e.g. UV or heat curing) that sets the film. The substrates can subsequently be removed if required.

[0104] FIG. 6 shows bow images of the AFS process are taken:

[0105] Imaging of AFS process in film. An inverted microscope is used to image the system. Changes in height can be observed by the change in the diffraction pattern of the particle. The images in FIG. 8-13 were taken using this technique. Principle of Acoustic Force Spectroscopy, (a) The experimental setup consists of the Acoustic Force Spectroscopy device integrated in a flow cell. The optics used for imaging are: an inverted microscope to equipped with a microscope objective lens (OL), a digital camera (CMOS), a LED light source (455 nm) and a 60/50 beam splitter (BS). (b) The flow cell consists of two glass plates with a fluid chamber in between. For illumination purposes, the upper glass slide has a sputtered mirroring aluminum layer on top. A piezo plate is glued on fop of the mirror. Similar to the flow cell, a film can be viewed.

[0106] FIG. 7 shows an AFS process in a glass plate flow cell with a fluid channel in between. The acoustic wave is created by the piezo element. A standing wave is created by bringing the system in resonance. Microspheres that are flushed in the fluid layer are pushed toward the node of the acoustic standing wave. These can be imaged using inverted microscopy (FIG. 6). Similar to the flow cell, a film can be viewed.

[0107] FIGS. 8a, b, c shows how the AFS process is used on micro-organisms. The frequencies (F) were FIG. 8a: F=0 Hz , FIG. 8b: F=1950 kHz and FIG. 8c: F=5770 kHz. The fluid channel is shown from the side.

[0108] FIG. 9: 4.5 m polystyrene beads (0.01-0.1 vol %) low concentration. (A) When applying the acoustic force, beads are pushed in two nodes, as expected from this system. (B) Beads are also attracted by each other. If beads are close enough they cluster together. (C) When a different resonance frequency is applied the beads are pushed to another plane.

[0109] FIG. 10: increasing the concentration (1-10%) to by a 100 fold 4.5 m bead. (A) Force off. (B) Force on. (C) Force on, (D) Force on, different field of view. By increasing the concentration, beads are still pushed in to the node of the acoustic wave. Stronger bead to bead interaction is visible because the beads are closer to each other. Here longitudinal nodes are also visible, because of a resonance over the width of the flow channel By increasing the amplitude of the acoustic wave, beads are more clustered. By changing the resonance frequency, beads are still pushed to a different nodes.

[0110] FIG. 11: Sweep frequency 1-30 MHz in 30 sec is used here. Typically frequencies can range from 1 kHz to 100 MHz. Different times can be used, such as 1 s, 10 s, 30 s or 80 s or 240 s. In these images you can observe all the acoustic effects that can be applied on the beads with our system: The waves are pushing the beads to different heights/node of the body. There can be a bead to bead attraction that is clustering of the beads. The longitudinal nodes are at certain frequencies very strong.

[0111] FIG. 12: With smaller 2.1 m polystyrene beads it is observe that: The beads can still be pushed in a node. Bead are also clustering together T denotes the time steps following the application of the acoustic force.

[0112] FIG. 13: Kaolin is pushed towards the node. (A) Force off. Kaolin diffuses over the whole flow cell when no force is applied. (B) Force on. When the force is turned on kaolin is pushed on the acoustic node (this can be seen from the diffraction pattern). Over time the Kaolin clusters together.

[0113] FIG. 14: The bead position was tracked when if is pushed from the surface to a node. From the velocity of the bead the acoustic force can be determined. This method was used to study the effect on the viscosity. (A) Push head form the surface to a node. (B) Track the bead displacement. (C) Convert that into a force profile.

[0114] FIG. 15: Measured force response when viscosity is increased: 0, 10, 20 and 30% of glycerol was used to increase the viscosity and measure the effect on the force amplitude. The frequency is swept and fitted with a Lorentzian function. As can be seen from the fit: resonance is shifting upwards when the viscosity is increased, the width of the resonance is increased with increased viscosity and the force reduces with increasing viscosity. The viscosity also has an effect on the drag force. Pushing a bead in a node, the speed reduces because of the reduced acoustic force and the increased drag force.