An ultrasonic metamaterial containing an array of ordered microspheres and a preparation method thereof

Abstract

This invention discloses a method for preparing an ultrasonic metamaterial containing an ordered microsphere array: matrix microspheres are automatically arranged into a periodic distribution under gravity; a photocurable hydrogel precursor solution is added and cured; scattering microspheres are arranged in the gaps between the matrix microspheres, and a matrix material precursor solution is added and cured. This invention also discloses another preparation method: steel or iron beads are automatically arranged into a periodic distribution under gravity; a photocurable hydrogel precursor solution is added and cured; scattering microspheres are arranged in the gaps between the matrix microspheres and a matrix material precursor solution is added; the steel or iron beads are removed, and a matrix material precursor solution is added again and cured. This invention also discloses an ultrasonic metamaterial containing an ordered microsphere array obtained by the above methods. This method can easily and readily achieve a controllable periodic distribution of micron-sized microsphere scattering array elements in ultrasonic metamaterials.

Claims

1. A method for preparing an ultrasonic metamaterial containing an ordered microsphere array, characterized in that, The preparation method includes: (1-1) The matrix material was prepared into monodisperse matrix microspheres by microfluidics and automatically arranged into a periodic distribution under the action of gravity; (1-2) Add a photocurable hydrogel precursor solution with a height not exceeding 1 / 3 of the diameter of the matrix microspheres and cure it; (1-3) The microfluidically prepared scatterer microspheres are uniformly arranged in the gaps between the matrix microspheres and the matrix material precursor solution is added. (1-4) Solidify the matrix material precursor solution to prepare an ultrasonic metamaterial containing an ordered microsphere array; The matrix material is a hydrogel, selected from sodium alginate, polyvinyl alcohol, chitosan, agarose, polyethylene glycol diacrylate, or methacrylated gelatin; the scattering microspheres are composed of a gel material, the raw materials of which include a curable gel material monomer, an auxiliary curing material, and water; the curable gel material monomer is selected from sodium alginate, polyvinyl alcohol, chitosan, agarose, polyethylene glycol diacrylate, or methacrylated gelatin, and the auxiliary curing material includes a photoinitiator and an ionic crosslinking agent; the concentration of the curable gel material monomer in the gel material is 5–40 wt%, and the concentration of the auxiliary curing material is 1–4 wt%; The diameter of the scattering microspheres is 100–1000 μm; the periodic distribution is either tetragonal or hexagonal, with a period of 0.5–3 mm. For a tetragonal arrangement, if the particle size of the matrix microspheres is a μm, then the particle size range of the periodically manipulated scatterer microspheres is: For a hexagonal arrangement, if the particle size of the matrix microspheres is a μm, then the particle size range of the periodically manipulated scatterer microspheres is:

2. An ultrasonic metamaterial containing an ordered microsphere array obtained by the preparation method of claim 1.

3. A method for preparing an ultrasonic metamaterial containing an ordered microsphere array, characterized in that, The preparation method includes: (2-1) Steel balls or iron balls are automatically arranged into a periodic distribution under the action of gravity; (2-2) Add a photocurable hydrogel precursor liquid with a height not exceeding 1 / 3 of the diameter of the steel ball or iron ball and cure it; (2-3) The microfluidically prepared scatterer microspheres are uniformly arranged in the gaps between the matrix microspheres and the matrix material precursor solution is added; (2-4) Remove the steel or iron balls, add the matrix material precursor solution again, fill the pits and solidify to obtain an ultrasonic metamaterial containing an ordered microsphere array. The matrix material is a hydrogel or PDMS, wherein the hydrogel is selected from sodium alginate, polyvinyl alcohol, chitosan, agarose, polyethylene glycol diacrylate, or methacrylated gelatin; the scattering microspheres are composed of a gel material, wherein the raw materials of the gel material include a curable gel material monomer, an auxiliary curing material, and water; the curable gel material monomer is selected from sodium alginate, polyvinyl alcohol, chitosan, agarose, polyethylene glycol diacrylate, or methacrylated gelatin, and the auxiliary curing material includes a photoinitiator and an ionic crosslinking agent; the concentration of the curable gel material monomer in the gel material is 5–40 wt%, and the concentration of the auxiliary curing material is 1–4 wt%; The scatterer microspheres have a diameter of 100–1000 μm and are periodically distributed in a tetragonal or hexagonal pattern with a period of 0.5–3 mm. For a tetrahedral arrangement, if the particle size of the steel or iron beads is a μm, then the range of scattering microsphere particle sizes that can be periodically manipulated is: For a hexagonal arrangement, if the particle size of the steel or iron beads is a μm, then the range of periodically controllable scattering microsphere particle sizes is:

4. An ultrasonic metamaterial containing an ordered microsphere array obtained by the preparation method of claim 3.

Images