Material fabrication using acoustic radiation forces

Patent metadata

Field	Value
Publication number	US-10124311-B2
Application number	US-201514955482-A
Country	US
Kind code	B2
Filing date	Dec 1, 2015
Priority date	Mar 12, 2010
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

Apparatus and methods for using acoustic radiation forces to order particles suspended in a host liquid are described. The particles may range in size from nanometers to millimeters, and may have any shape. The suspension is placed in an acoustic resonator cavity, and acoustical energy is supplied thereto using acoustic transducers. The resulting pattern may be fixed by using a solidifiable host liquid, forming thereby a solid material. Patterns may be quickly generated; typical times ranging from a few seconds to a few minutes. In a one-dimensional arrangement, parallel layers of particles are formed. With two and three dimensional transducer arrangements, more complex particle configurations are possible since different standing-wave patterns may be generated in the resonator. Fabrication of periodic structures, such as metamaterials, having periods tunable by varying the frequency of the acoustic waves, on surfaces or in bulk volume using acoustic radiation forces, provides great flexibility in the creation of new materials. Periodicities may range from millimeters to sub-micron distances, covering a large portion of the range for optical and acoustical metamaterials.

First claim

What is claimed is:

1. An apparatus for fabricating materials, the apparatus comprising:
an acoustic resonator comprising a cavity defined by two sets of opposing, parallel spaced-apart resonator walls, each of said walls having an outer surface and an acoustically reflecting inner surface configured to contain a static quantity of particles suspended in a solidifiable fluid in said cavity;
an acoustic transducer arranged against the outer surface of at least one of the opposed walls of each of the two sets of walls;
a waveform generator configured to generate a chosen waveform applied to each of the transducers to produce a chosen wavelength of intersecting acoustic standing waves in the both solidifiable fluid contained in said cavity and within each of the walls of the two sets of walls for a sufficient time that the suspended particles migrate to pressure nodes or pressure antinodes of the intersecting standing waves to form a two-dimensional pattern of the suspended particles in the solidifiable fluid; and
means for solidifying the solidifiable fluid to form a solidified fluid fixing the formed two-dimensional pattern of particles therein.

2. The apparatus of claim 1 , wherein the chosen wavelength, as λ, of the standing waves is selected such that a chosen number of the pressure nodes and a selected number of the pressure antinodes are generated in said acoustic resonator.

3. The apparatus of claim 2 , wherein the pressure nodes are spaced apart by λ/2, and wherein the pressure antinodes are spaced apart by λ/2.

4. The apparatus of claim 1 , wherein the acoustic resonator cavity is further defined by a third set of the opposing, parallel spaced-apart walls, whereby an acoustic transducer is arranged against the outer surface of one of the opposing walls of the third set of walls, wherein the waveform generator is further configured to generate the chosen waveform applied also to the transducer of the third set of walls, and wherein the formed and fixed pattern is a three-dimensional pattern of the particles.

5. The apparatus of claim 4 , wherein the acoustic resonator comprises a cube-shaped cuvette.

6. The apparatus of claim 1 , wherein the acoustic transducers are arranged against the outer surface of each of the opposed walls of each of the two sets of walls.

7. The apparatus of claim 1 , further configured to generate the intersecting standing waves orthogonal to one another.

8. The apparatus of claim 1 , wherein the particles are elongated, and wherein the elongated particles are oriented by the standing waves.

9. The apparatus of claim 1 , wherein the particles comprise hollow microspheres.

10. The apparatus of claim 9 , wherein the hollow microspheres are expandable gas-filled microspheres, and wherein the solidified fluid is elastic.

11. The apparatus of claim 1 , wherein the particles comprise particles of more than one composition.

12. The apparatus of claim 1 , wherein the particles comprise particles having positive acoustic contrast factors and particles having negative acoustic contrast factors.

13. The apparatus of claim 1 , wherein the particles comprise particles having more than one size.

14. The apparatus of claim 1 , wherein the standing waves are generated using amplitude-modulated acoustic carrier frequencies produced by each of the transducers.

15. The apparatus of claim 1 , wherein the materials fabricated by the apparatus comprise phononic metamaterials.

16. The apparatus of claim 1 , wherein the materials fabricated by the apparatus comprise photonic metamaterials.

17. The apparatus of claim 1 , wherein the fluid comprises at least one epoxy.

18. The apparatus of claim 1 , wherein the solidified fluid is configured to be dissolved, thereby leaving layers of the suspended particles.

19. The apparatus of claim 1 , wherein the acoustic resonator comprises a glass cuvette having a square or rectangular geometry.

Assignees

• Los Alamos Nat Security Llc

Inventors

• Sinha Naveen N
• Sinha Dipen N
• Goddard Greg R

Classifications

• B29C37/00

  Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00 · CPC title

• B29K2063/00

  Use of {EP, i.e.} epoxy resins {or derivatives thereof}, as moulding material · CPC title

• G10K11/165

  Particles in a matrix · CPC title

• B29K2995/0094

  Geometrical properties · CPC title

• B29C2791/008

  Using vibrations during moulding · CPC title