title: Toughening through nature-adapted nanoscale design.
abstract: The extraordinary combination of strength and toughness attained by nature's highly sophisticated structural design in nacre has inspired the synthesis of novel nanocomposites. In this context, the organic-inorganic hierarchical design of nacre has been mimicked. However, two key features of nacre, namely the scaling of the structural components and the low content of the organic phase, have not been replicated yet. Here, we present thin nanocomposite films with properly adjusted thicknesses of the organic and inorganic layers, as well as a microstructure that closely resembles that of nacre. These films, which are obtained by the combination of low-temperature chemical bath deposition of titania with layer-by-layer assembly of polyelectrolytes, exhibit enhancement in a fracture toughness by a factor of 4, combined with notable increase in hardness, while the Young's modulus is largely preserved in comparison to the single titania layer. Our findings highlight the significance of the 10:1 inorganic/organic layer thickness ratio evolved by nature, and provide novel perspectives for the future development of efficient bioinspired thin films.
authors.affiliation: Institute for Material Science, University of Stuttgart, Heisenbergstrasse 3, D-70569 Stuttgart, Germany. zburghard@mf.mpg.de
authors.forename: Zaklina
authors.initials: Z
authors.lastname: Burghard
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Zini
authors.forename: Vesna
authors.initials: V
authors.lastname: Srot
authors.forename: Paul
authors.initials: P
authors.lastname: Bellina
authors.forename: Peter A van
authors.initials: PA
authors.lastname: Aken
authors.forename: Joachim
authors.initials: J
authors.lastname: Bill
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D055119:Elastic Modulus; D006244:Hardness; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances