Material fabrication using acoustic radiation forces

Patent metadata

Field	Value
Publication number	US-2016184790-A1
Application number	US-201514955482-A
Country	US
Kind code	A1
Filing date	Dec 1, 2015
Priority date	Mar 12, 2010
Publication date	Jun 30, 2016
Grant date	—

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 . A method for fabricating materials, comprising the steps of:
suspending particles in a solidifiable fluid; generating at least one acoustic standing wave having a chosen wavelength in the liquid for a sufficient time that the suspended particles migrate to at least one pressure node or at least one pressure antinode of the at least one standing wave; and solidifying the fluid.

2 . The method of claim 1 , wherein the particles comprise particles having more than one size.

3 . Apparatus for fabricating materials, comprising:
an acoustic resonator cavity for containing a static quantity of a suspension of particles in a solidifiable fluid; and means for generating at least one acoustic standing wave having a chosen wavelength in the liquid for a sufficient time that the suspended particles migrate to at least one pressure node or at least one pressure antinode of the at least one standing wave forming a pattern; wherein the fluid is solidified to fix the pattern.

4 . The apparatus of claim 3 , wherein the wavelength, λ, of the standing wave is selected such that a chosen number of pressure nodes and a selected number of antinodes are generated in said acoustic resonator.

5 . The apparatus of claim 4 , wherein the pressure nodes are spaced apart by λ/2, and the antinodes are spaced apart by λ/2.

6 . The apparatus of claim 3 , wherein said means for generating at least one acoustic standing wave comprises at least one acoustic transducer and at least one opposing reflective surface.

7 . The apparatus of claim 3 , wherein said means for generating at least one acoustic standing wave comprises at least one acoustic transducer and at least one opposing acoustic transducer.

8 . The apparatus of claim 3 , wherein the at least one acoustic standing wave is generated in greater than one-dimension.

9 . The apparatus of claim 3 , wherein the particles are elongated, and wherein the elongated particles are oriented by the at least one acoustic standing wave.

10 . The apparatus of claim 3 , wherein the particles comprise hollow microspheres.

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

12 . The apparatus of claim 3 , wherein the particles comprise particles having more than one composition.

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

14 . The apparatus of claim 12 , wherein the particles comprise particles having more than one size.

15 . The apparatus of claim 3 , wherein the at least one standing wave is generated using amplitude-modulated acoustic waves.

16 . The apparatus of claim 3 , wherein the material comprises phononic metamaterials.

17 . The apparatus of claim 3 , wherein the material comprises photonic metamaterials.

18 . The apparatus of claim 3 , wherein the fluid comprises at least one epoxy.

19 . The apparatus of claim 3 , wherein the solidified fluid is removed.

20 . The apparatus of claim 3 , wherein the acoustic resonator cavity comprises a piezoelectric cylinder.

Assignees

• Los Alamos Nat Security Llc

Inventors

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

Classifications

• B29K2995/0094

  Geometrical properties · CPC title

• G10K11/165

  Particles in a matrix · CPC title

• B29K2063/00

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

• B29C37/00

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

• B29C2791/008

  Using vibrations during moulding · CPC title