Hypersonic phononic particle brush materials E.Alonso-Redondo1, R.Sainidou2, P.Rembert2 M. Bockstaller3, K. Matyjaszewski4 ,G. Fytas1,5 1 Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany Laboratoire Ondes et Milieux Comlexes,UMR CNRS 6294,University of Le Havre, France 3Department of Materials Science and Engineering and 4Chemistry Department of Carnegie Mellon University, Pittsburgh PA 15213 5 Department of Materials Science, University of Crete and IESL-FORTH, 71110 Heraklion, Greece Realization of new polymer properties is very often bound to progress in polymer chemistry. The synthesis of multi-arm star polymers, more than twenty years ago, provided the ground to apply new physical concepts for the chain conformation and their assembly characteristics. Recent progress in surface-initiated controlled radical polymerization has enabled the synthesis of particle brush materials with controlled architecture of the grafted chains. The tethering of the chains to a curved solid surface opens new fundamental and applied perspectives to these hierarchically hybrid organized materials. Two intriguing behaviors will be discussed. In the first, the distinctive change of the vibrational eigenmodes (music) of the individual particle brushes compared to uniform core-shell particles has been experimentally revealed by Brillouin light scattering. The eigenfrequencies can only be theoretically described by assuming imperfect boundary conditions and anisotropic elastic properties of the grafted polymer layer. The second part of this presentation will present the collective phonon dispersion (concert) in the assembled particle brushes revealing a hypersonic phononic band gap of different nature than in colloidal crystals of hard and core-shell spheres. It is not a structure directed (Bragg) interference phononic gap but a particle induced hybridization gap (HG). Based on the elastodynamic theory a low frequency core resonance mode (l=1) modified in the particle brush and their array. is at the origin of this new HG. The unique phonon (elastic wave) propagation in particle brush materials emphasizes a rich parameter- space for controlling new properties such as thermal and optomechanical response in hybrid materials. Polymer chemistry plays a central role also in this development assessing the necessary material parameters at nanoscale.

Hypersonic phononic particle brush materials

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Hypersonic phononic particle brush materials<br />