ICMCTF 2012! - CD-Lab Application Oriented Coating Development

Plenary Session
Monday, April 23, 2012, 8:00 am
Golden Ballroom
How Interfaces Control the Mechanical
Behavior of Biological Materials
Professor Peter Fratzl
Director of the Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
Peter Fratzl is director at the Max Planck Institute of Colloids and Interfaces in Potsdam,
Germany, and honorary professor of physics at Humboldt University, Berlin, and at Potsdam
University. He received an engineering degree from the Ecole Polytechnique in Paris, France
(1980), and a doctorate in Physics from the University of Vienna, Austria (1983). Before
moving to Potsdam in 2003, he has been holding professor positions in materials physics at
the Universities of Vienna and Leoben in Austria and been director of the Erich Schmid
Institute of Materials Science of the Austrian Academy of Sciences.
Peter Fratzl’s lab studies the relation between (hierarchical) structure and mechanical
behaviour of biological materials, such as mineralized tissues, extracellular matrix, or plant
cell walls, as well as bio-inspired composite materials. This is complemented by medically
oriented research on osteoporosis and bone regeneration. Peter Fratzl has published more than 350 papers in journals
and books, mostly on interdisciplinary materials science topics. He received several international awards for
his work including the Max Planck Research Award 2008 from the Humboldt Foundation (together with Robert
Langer, MIT) and the Leibniz Award 2010 of the German Science Foundation. In 2010, he was awarded an
honorary doctorate from the University of Montpellier, France, and since 2007 he is foreign member of the Austrian
Academy of Sciences.
ABSTRACT
Biological materials, such as wood, grasses, protein fibres, bone, sea shells or glass sponges are generally composites
of different types of polymers as well as mineral. These materials are able to adapt to the mechanical requirements
of the environment by growing and assembling structural components in a hierarchical fashion. This implies
the existence of various types of interfaces at all levels of hierarchy. From a mechanical viewpoint, interfaces may
be considered as defects but, in many natural materials, interface structures emerged which improve rather than
deteriorate the overall mechanical properties of the composite. Bone, for example, consists in about equal amounts
of a collagen-rich matrix and calcium-phosphate nano-particles. These components are joined in a complex hierarchy
of fibres and lamellar structures to a material with exceptional fracture resistance. Similarly, tendon collagen
consists of an assembly of fibrils which partly deform by shearing the interface between them. An example for selfhealing
properties due to molecular-scale interfaces is the byssus fibre used by mussels to attach to rocks. These
fibres combine large deformation with stiffness and abrasion resistance. Finally, plant cell walls generate internal
stresses and even complex movements upon changes of environmental humidity. This force generation and actuation
capabilities are based on water swelling of hemicellulose-rich interfaces between cellulose microfibrils
arranged in complex architectures. Unravelling the structural principles of these unexpected material properties
may indicate ways towards new types of composite materials with adaptive capabilities.
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