Rational Design of Bulk Ultrasonic Metamaterials – Metakoustik

Fabrication: Microfluidics, Formulation, Emulsification
Acoustic characterization: acoustic attenuation and transmission measurements

Result 1: Measurements of intense resonance peaks
Result 2: First measurements of a negative refractive index
Result 3: Synthesis of metallic particles of tunable size and shape

Core-shell system: We have identified a realistic experimental situation to reach highly resonant core-shell systems. This implies the realization of thin shell of 1/10th of the core in size, which should be made of a PDMS type of polymer.
Resonant emulsions: We must increase the sound speed contrast between the inclusions and the suspending matrix. We have identified two possible ways: silica aerogels or porous polymers.

Publications
1. ‘Millifluidic production of metallic microparticles’, Rawad Tadmouri, Marta Romano, Fabien Guillemot, Olivier Mondain Monval, Régis Wunenburger, Jacques Leng, Soft Matter 8, 10704 (2012)
2. ‘Constraints on the design of core-shell resonators of locally resonant acoustic metamaterials’, L. Bos, L. Lukyanova, R.Wunenburger, Physical Review B 86, 184107 (2012)
3. ‘Sharp acoustic multipolar-resonances in highly monodisperse emulsions’, T. Brunet, S. Raffy, B. Mascaro, J. Leng, R. Wunenburger, O. Mondain-Monval, O. Poncelet and C. Aristégui, Applied Physics Letters 101, 011913 (2012)
4. ‘Microfluidic synthesis of core-shell particles: toward micro-mechanical resonators for acoustic metamaterials’, L. Lukyanova, L. Séon, A. Aradian, O. Mondain-Monval, J. Leng, R. Wunenburger, Journal of Applied Polymer Science 128 (6), 3512–3521 (2013)
5. ‘Impact of polydispersity on multipolar resonant scattering in emulsions’, B. Mascaro, T. Brunet, O. Poncelet, C. Aristégui, S. Raffy, O. Mondain-Monval, J. Leng, Journal of the Acoustical Society of America 133 (4), 1996 (2013)
6. 'Soft Acoustic Metamaterials', Thomas Brunet, Jacques Leng, Olivier Mondain-Monval, Science 342, 323 (2013)
7. 'Tuning Mie scattering resonances in soft materials with magnetic fields', Thomas Brunet, Kevin Zimny, Benoit Mascaro, Olivier Sandre, Olivier Poncelet, Christophe Aristégui, Olivier Mondain-Monval, Physical Review Letters 111, 264301 (2013)
8. 'Design of a fluorinated magneto-responsive material with tunable acoustic properties', Kevin Zimny, Benoit Mascaro, Thomas Brunet, Olivier Poncelet, Christophe Aristégui, Jacques Leng, Olivier Sandre, and Olivier Mondain-Monval, Journal of Materials Chemistry B 2, 1285 (2014)

This project aims at the design, the synthesis and characterization of new acoustic metamaterials acting in the ultrasonic frequency range (f > 20 kHz). We propose to exploit state-of-the-art microfluidic techniques and advanced emulsification and formulation techniques for the fabrication of soft-matter based, sophisticated colloidal objects, in the size range of about 1 to 100 µm, acting as locally resonant inclusions and exhibiting unusual acoustic properties. By tuning the nature, the size, the composition, and the elastic properties of our inclusions, we target:
- negative effective density materials or negative compression modulus materials, which could be used as enhanced absorbing materials or as perfect acoustic mirrors;
- double negative materials, which would exhibit the negative refraction property and could be used as perfect planar acoustic lens