Karl Franzens University Graz
Graz University of Technology
Bio-enabled Nanocomposites with Unique Physical Properties
Bio-enabled nanocomposites represent a novel class of functional materials, which uses principles of bioinspiration and biomimetic to design hybrid materials and structures with co-assembled biological and synthetic components to bring best of two worlds: versatile functions with responses to mechanical, optical, chemical, and light stimuli and mechanical strength, flexibility, environmental robustness, and scalability (see general reviews [1-4]). We discuss general principles of organization in most popular biological components frequently explored for bio-hybrid materials including polynucleotides (DNA), proteins (silk fibroins), polysaccharides (nanocelluloses) and common synthetic components such as metal and semiconducting nanoparticles/nanowires and two-dimensional nanoclays and graphene derivatives. For specific illustrations, we select recent results from our research group on designing flexible and strong nanomaterials with electrical conductivity, actuation, bright emission, and controlled photonic properties. In particular, we demonstrated robust patterned metallized biographene papers from graphene oxide monolayers “glued” by silk fibroins with intriguing biosensing properties and corresponding Kirigami structures with huge stretchability and ability to transform from planar to 3D structures. Secondly, we fabricated uniformly aligned chiral photonic films from a liquid crystal phase in a thin capillary to facilitate homogeneous growth of chiral pseudo-layers with an intense iridescence from rod-like cellulose nanocrystals. Bright chiral emission has been demonstrated in organized biopolymer photonic films with embedded carbon quantum dots mediated by polymer linkers. Finally, co-assembly of cellulose nanocrystals with amorphous polysaccharides resulted in the formation of flexible films with the preservation of the original structural colors and control of the chiral pitch length due to intercalation into the interstitial defects of nematic monolayers.