title: Directional elastic wave propagation in high-aspect-ratio photoresist gratings: liquid infiltration and aging.
abstract: Determination of the mechanical properties of nanostructured soft materials and their composites in a quantitative manner is of great importance to improve the fidelity in their fabrication and to enable the subsequent reliable utility. Here, we report on the characterization of the elastic and photoelastic parameters of a periodic array of nanowalls (grating) by the non-invasive Brillouin light scattering technique and finite element calculations. The resolved elastic vibrational modes in high and low aspect ratio nanowalls reveal quantitative and qualitative differences related to the two-beam interference lithography fabrication and subsequent aging under ambient conditions. The phononic properties, namely the dispersion relations, can be drastically altered by changing the surrounding material of the nanowalls. Here we demonstrate that liquid infiltration turns the phononic function from a single-direction phonon-guiding to an anisotropic propagation along the two orthogonal directions. The susceptibility of the phononic behavior to the infiltrating liquid can be of unusual benefits, such as sensing and alteration of the materials under confinement.
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany. fytas@mpip-mainz.mpg.de.
authors.forename: E
authors.identifier: http://orcid.org/0000-0001-5984-5057
authors.initials: E
authors.lastname: Alonso-Redondo
authors.affiliation: Institut d'Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR-CNRS 8520, UFR de Physique, Université de Lille 1, 59655 Villeneuve d'Ascq, France and LPMR, Département de Physique, Faculté des Sciences, Université Mohamed I, 60000 Oujda, Morocco.
authors.forename: A
authors.initials: A
authors.lastname: Gueddida
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA 19104, USA.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and the Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Graczykowski
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and the Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra, Spain and ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain.
authors.forename: C M
authors.initials: CM
authors.lastname: Sotomayor Torres
authors.affiliation: Institut d'Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR-CNRS 8520, UFR de Physique, Université de Lille 1, 59655 Villeneuve d'Ascq, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Pennec
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA 19104, USA.
authors.forename: S
authors.initials: S
authors.lastname: Yang
authors.affiliation: Institut d'Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR-CNRS 8520, UFR de Physique, Université de Lille 1, 59655 Villeneuve d'Ascq, France.
authors.forename: B
authors.initials: B
authors.lastname: Djafari-Rouhani
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany. fytas@mpip-mainz.mpg.de and Department of Materials Science, University of Crete and IESL/FORTH, 71110 Heraklion, Greece.
authors.forename: G
authors.initials: G
authors.lastname: Fytas