Liquid crystal templating of nanomaterials with nature's toolbox

Naturally occurring biomolecules are sustainable and green precursors for the development of new materials. Within this family of natural materials, cellulose nanocrystals (CNCs) have emerged as one of the most promising materials because of their outstanding physico-chemical properties and the possibility to produce them in large quantities. One key trait of CNCs is their ability to self-assemble into a chiral nematic liquid crystalline phase. In this review, we discuss how templating can be used to transfer the three-dimensional structure of liquid crystalline CNC phases onto solid materials. This is followed by examples that illustrate the fascinating properties and potential applications that arise from the resulting nanostructured materials such as sensing and catalysis. We then summarize efforts to use the liquid crystalline phase of a selection of other biopolymers for templating. While nanocrystalline chitin, having very similar properties to CNCs, has been successfully employed to make a variety of new materials, efforts to template liquid crystal phases of other biomolecules have been met with limited success. However, we discuss virus nanoparticles and collagen as examples to highlight further possibilities for materials research. (C) 2017 Elsevier Ltd. All rights reserved.