Metal Nanopatterning of Flexible Substrates by Surface Mechanical Activation – MetaFleSS

The fabrication of miniaturized electronic, chemical and photonic components on flexible, stretchable, non-planar, and biocompatible substrates as opposed to conventional rigid substrates can open doors for the next generation of advanced devices with new functionalities. In this context, one great challenge consists in the development of new technologies to generate, localized and stabilize metallic nano-objects on flexible surfaces by industrially viable processes. The existing protocols to fabricate metallic nanostructures could be demonstrated only on limited resolution and/or small surfaces. These techniques usually involve multiple steps such as pattern transfer that are difficult to perform on polymeric substrates at the nanoscale without degradation and delamination of the nanostructures. The MetaFleSS project aims to develop of a simple, environmental-friendly and scalable nanofabrication technique to in-situ generate, localize and anchor metal nano-objects on flexible substrates. The approach is based on metal reduction induced by mechanical homolysis of the surface, recently demonstrated in the literature and by our preliminary results. During mechanical pulling-off, local homolytic bond breaking induces formation of “mechanoradicals” on the surface that act as reducing sites; the metal reduction takes place after immersion in metal precursors aqueous solutions leading to the formation of metal nanoparticles patterns on the surface. In order to better control the radical formations, the contact interface will be rationally designed. In the first part of the project, the homolysis-assisted reduction process will be investigated. The first objective is thus to access the mechanoreactivity of the hybrid interface on flat surfaces in order to understand the mechanism of formation of metallic nanoparticle, with optimized size and density. The second objective of the project will be to explore the potentiality of this simple approach for nanopatterning. In order to optimize the radicals formation and spatially localized the reduction process, the hybrid interface will be rationally designed by using topographic and chemical heterogeneities. Patterned ceramic masters obtained by nanoimprinting lithography or/and micelles self-assembly will be used to explore the limit of the approach in term of geometry and resolution. Finally the properties of the flexible/stretchable nanopatterned metallic components will be tested in order to develop functional devices such as stretchable plasmonic sensors.