Composites of the future: towards soft-hard hybrids with molecular definition for electronics, optics, and health

Nanocomposites contain inorganic nanoparticles that change the molecular structure of a polymer and improve the mechanical properties of the combination. Such hybrids are ubiquitously used in a wide range of products, from car tires to dental fillings and in electronics packaging. They are fully accepted in industry and constitute a market with a considerable volume.

And yet, the level of control over structure and properties in nanocomposites is rudimentary when we compare them to biogenic materials that even simple organisms form in nature. We strive to reach a similar level to control and create new hybrid materials with optimal hierarchical structure from molecules to parts. Here, I will discuss our bioinspired route that from the shape-controlled synthesis of inorganic particles, organic shells on the cores and evaluation of their effect on colloidal and material properties, and the preparation and microstructuring of particle-based macroscopic materials. Our goal are hybrid materials that connect mechanical, electronic, and optical properties in new ways: for example, soft, transparent and flexible conductors that can establish electrical contact to living tissues.

Two examples will illustrate the principles. Ultrathin metal wires have inorganic cores with diameters below 2 nm and are only stable due to an organic ligand shell that we use to assemble them into fibers and electrical circuits. Hybrid electronic inks are based on spherical or rod-shaped cores that carry electrically conductive shells and become conductivity immediately after drying, enabling sinter-free electronic prototyping.