title: Soft porous silicone rubbers as key elements for the realization of acoustic metamaterials.
abstract: In this work, macroporous materials made of polydimethylsiloxane, a soft silicone rubber, are prepared using UV polymerization with an emulsion-templating procedure. The porosity of the final materials can be precisely controlled by adjusting the volume of the dispersed phase. We show that the porous structure of the materials is the template of the droplets of the initial emulsions. Mechanical tests show that the materials Young's moduli decrease with the porosity of the materials. Acoustic measurements indicate that, in such a porous elastomeric matrix, the sound speed also decreases dramatically as soon as the porosity increases to attain values of as low as 80 m/s. The results are compared to earlier ones on silica aerogels and are interpreted within the framework of a simple theoretical approach. We show that the very low sound speed value is a consequence of the low value of the polymer shear modulus. This explains why such porous soft silicone rubbers are so efficient at playing the role of slow-soft resonators in acoustic metamaterials. Moreover, the fast rate of polymerization of such UV-curable fluid allows for a facile shaping of the final material as beads or rods in microfluidic devices.1.
authors: †University of Bordeaux - CNRS, Centre de Recherche Paul Pascal, Pessac, France.
authors: Kévin
authors: K
authors: Zimny
authors: †University of Bordeaux - CNRS, Centre de Recherche Paul Pascal, Pessac, France.
authors: Aurore
authors: A
authors: Merlin
authors: ‡University of Bordeaux - CNRS - INPB, Institut de Mécanique et d'Ingénierie, Talence, France.
authors: Abdoulaye
authors: A
authors: Ba
authors: ‡University of Bordeaux - CNRS - INPB, Institut de Mécanique et d'Ingénierie, Talence, France.
authors: Christophe
authors: C
authors: Aristégui
authors: ‡University of Bordeaux - CNRS - INPB, Institut de Mécanique et d'Ingénierie, Talence, France.
authors: Thomas
authors: T
authors: Brunet
authors: †University of Bordeaux - CNRS, Centre de Recherche Paul Pascal, Pessac, France.
authors: Olivier
authors: O
authors: Mondain-Monval