Rigid biological composite materials: Structural examples for biomimetic design

Abstract

ABSTRACT--Biological hard tissues are composites of inorganics and biopolymers, and, therefore, represent hybrid systems. The inorganic components may be oxides (e.g., SiO2, Fe304), carbonates (e.g., CaCO3) sulfides (e.g., FeS, CdS), or others, mostly in crystalline forms but also occasionally in glassy forms. The biopolymer is often proteinaceous, but can also involve lipids and especially polysaccharides (e.g., chitin). These hybrid materials can be found in single celled organisms (such as bacteria and protozoa), invertebrates (such as mollusks), insects (such as beetles), and vertebrates (such as mammals). A common denominator of all hard tissues is that they are hierarchically structured from the nanometer scale to the microscale and the macroscale. It is these controlled structures that give biological hard tissues their unique and highly evolved functional properties. The engineering properties include mechanical, piezoelectric, optical, and magnetic. The hard tissues can be in the form of nanoparticles, spines, spicules, skeletons, and shells. The objective of this paper is to demonstrate mechanical aspects of some of these hard tissues, to discuss their structure-function relationships (with examples from the literature as well as from our research), and to reveal their potential utility in materials science and engineering applications.

Biomechanics of the stick insect antenna: Damping properties and structural correlates of the cuticle

“…Previous studies have also shown structural correlates between composite materials and physical properties in various biological systems, including bacteria, molluscs, vertebrates and insects (Hepburn and Chandler, 1976;Lin et al, 2009;Mayer and Sarikaya, 2002;Sun et al, 2008;Williams and Kramer, 2010). It thus seems likely that the distinct physical properties within the flagellum's cuticle might correlate with its unique physical properties, combining stiffness with flexibility and controllability.…”

Structure and mechanical properties of selected protective systems in marine organisms

“…These differences result in the exocuticle being both harder and stiffer than the endocuticle [133,137,[140][141][142]. As the exocuticle increases in hardness toward the interface with the endocuticle, there is an [161], (e) [158] (f) [215]. abrupt change in both hardness and stiffness of more than an order of magnitude between these two layers [137].…”

Micromechanics and Macromechanics of the Tensile Deformation of Nacre

“…However, nacre, through its "brick and mortar" composite structure of micronscale tablets and sub-micron scale adhesive protein-rich layers, enables outstanding mechanical performance including an excellent combination of stiffness, strength, impact resistance, and toughness (Curry, 1977;Weiner and Traub, 1984;Jackson et al, 1988). The ability of nacre to optimize mechanical performance by properly organizing materials at different length scales has attracted a large interest in developing biomimetic materials (e.g., He et al, 1997;Mayer and Sarikaya, 2002), which, in turn, necessitates a deep understanding of the biological mechanisms responsible for its superior properties.…”