Towards mechanical characterization of nano-scale interfaces in biocomposite materials.

• Applicant: Dr. Igor Zlotnikov
• Subject Area: Polymeric and Biogenic Materials and Derived Composites ; Materials in Sintering Processes and Generative Manufacturing Processes ; Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 443727504

Identifying the property‐structure‐function relationships in mineral‐organic biocomposite materials is one of major challenges in today’s biomaterials science that incorporates research efforts in biology, chemistry, physics and engineering. The cross‐disciplinary interest in the topic stems from the efficiency of the biochemical machinery that is responsible for biotic mineral formation, the unconventional functional capacity of these tissues and, at the same time, elegance and even simplicity of “engineering” solutions it provides to the organisms. Specifically, nature is successful in forming complex hierarchical biocomposites with superior mechanical properties that provide the animals with high stiffness, high toughness and in some cases, are adapted for functional requirements that involve viscous damping, such as impact absorption, signal filtering and vibrations inhibition. In highly mineralized tissues, the stiff and hard mineral building blocks at all hierarchical levels are usually joined together by ultra‐thin compliant, soft and viscoelastic organic interfaces that, in some cases, are only few nanometers thick. Although these interfaces comprise merely a small volume fraction of the biocomposite structures, the performance of the entire tissue is considered to be substantially affected by their mechanical characteristics. However, our understanding of the contribution of the organic interfaces to the mechanical functionality of these biocomposite assemblies is limited, mainly, because we still lack the capacity to assess their nano‐mechanical properties. The current proposal is, thus, driven by the following research goal: to develop experimental‐numerical and experimental‐analytical strategies to characterize the viscoelastic properties of organic interfaces in biocomposite architectures and to correlate them with the frequency‐ and humidity‐dependent behavior of the tissue as a whole. To achieve this goal, we propose to study the laminar mineral‐organic architectures taken from three different organisms that represent the three most common minerals found in living organisms: silica, aragonite and calcite. The investigation will be carried out by adapting and reinventing state‐of‐the‐art nano‐scale mechanical characterization techniques and will be supported by extensive numerical and theoretical analysis. The groups of Igor Zlotnikov at TU Dresden in Germany (expertise in structural and nanomechanical characterization of functional biomaterials) and of Benny Bar‐On at Ben‐Gurion University in Israel (expertise in multi‐scale mechanics) possess the appropriate and complementary skill sets and competencies, as well as the necessary equipment to successfully complete this project. The outcome of this research will not only allow us to answer an outstanding question in the field of biological materials, but the developed framework is expected to have a fundamental impact on future study and design of classical materials systems.

• DFG Programme: Research Grants
• International Connection: Israel
• International Co-Applicant: Professor Benny Bar-On, Ph.D.