Three-dimensional ultrasonic colloidal crystals

TL;DR

This paper demonstrates how three-dimensional ultrasonic standing pressure waves can be used to assemble colloidal particles into orthorhombic structures, enabling rapid tuning of acoustic properties for advanced metamaterial applications.

Contribution

It introduces a novel method for 3D colloidal assembly using ultrasonic radiation forces in a simple orthogonal system, expanding the design space for acoustic metamaterials.

Findings

Orthorhombic colloidal structures can be assembled with MHz standing waves.

The assembled structures enable rapid tuning of acoustic properties.

The method provides a new platform for dynamic acoustic metamaterials.

Abstract

Colloidal assembly represents a powerful method for the fabrication of functional materials. In this article, we describe how acoustic radiation forces can guide the assembly of colloidal particles into structures that serve as microscopic elements in novel acoustic metadevices or act as phononic crystals. Using a simple three-dimensional orthogonal system, we show that a diversity of colloidal structures with orthorhombic symmetry can be assembled with megahertz-frequency (MHz) standing pressure waves. These structures allow rapid tuning of acoustic properties and provide a new platform for dynamic metamaterial applications.