Several recent review articles and recommendations from the European community are calling for greener biocomposites made from plant-derived fiber and crop-derived materials to advance a key sustainability goal. In photonics, recent awareness has granted the emergence of innovative solutions using chemically purified wood and silk extracts. In phononics however, no sustainable approach has been investigated because there has been no observation of phonon-based biological functions at the supramolecular scale, making phononic bioinspired strategies inoperative. In this project, we want to invent what we call biobased phononic materials (BPM).
We have recently demonstrated that biological composites in the form of decellularized plant cell scaffolds can behave as phononic materials, including forbidding the propagation of elastic waves in select frequency ranges (i.e. band gaps). In these pioneering experiments, our biological composite was composed of a micron-thick onion cell epidermis with slender cell walls extruding up from it that resemble blind bore beehive structures. We measured the dispersion of sub-GHz surface acoustic waves (SAWs) in the onion composite, and revealed their interaction with compressional and flexural resonances of the wall structure, which open deep and wide band gaps.
The field of biological composites is expanding rapidly with applications in photonics, soft robotics and human augmentation, but has not yet met phononics. This project should be the start of a new research area of what we call “biophoNonics”, whereby biological materials are not copied, but are genetically engineered, harvested and used as phononic materials. In the years to come, we believe that the ability to tailor the genome by controlled mutations or gene editing in plants could provide a plausible, scalable, sustainable manufacturing route for future phononic materials design.
In the frame the ANR project BiophoNonics, we have obtained a 2-years postdoctoral contract. The objective of this postdoc will be to 1) improve the existing optical scheme to detect surface acoustic waves in plant epidermis, 2) analyse the results using finite element approaches and 3) analyse the influence of various genetic cues on the phononic gap formation in collaboration with our colleagues at ENS. The postdoc will have to carry out the necessary optical assembly and implement the acquisition on plant samples engineered by the biologists. This work will be supported by the expertise in optoacoustics of the host team.
Local collaborative network : The postdoc will work at ILM (Institute for light and matter, in Villeurbanne, France) in the Biophysics team. She/he will be supervised by Thomas Dehoux and Maroun Abi Ghanem. The preparation of the plant samples will be developed in collaboration with the team of our collaborator, Olivier Hamant from the lab Reproduction et Développement des Plantes (RDP).
Candidate background: The candidate will have a background in Physics/Engineering, with a focus on laser, acoustics or metamaterials. Will to work at the interface between physics and biology is required. Early career researchers are encouraged to apply.