Biomimetic model of a sponge-spicular optical fiber—mechanical properties and structure

Abstract

Nanomechanical properties, nanohardness and elastic modulus, of an Antarctic sponge Rosella racovitzea were determined by using a vertical indentation system attached to an atomic force microscope. The Rosella spicules, known to have optical waveguide properties, are 10–20 cm long with a circular cross section of diameter 200–600 μm. The spicules are composed of 2–10-μm-thick layers of siliceous material that has no detectable crystallinity. Measurements through the thickness of the spicules indicated uniform properties regardless of layering. Both the elastic modulus and nanohardness values of the spicules are about half of that of either fused silica or commercial glass optical fibers. The fracture strength and fracture energy of the spicules, determined by 3-point bend tests, are several times those of silica rods of similar diameter. These sponge spicules are highly flexible and tough possibly because of their layered structure and hydrated nature of the silica. The spicules offer bioinspired lessons for potential biomimetic design of optical fibers with long-term durability that could potentially be fabricated at room temperature in aqueous solutions.

Biological materials: Structure and mechanical properties

“…36b. The mechanical toughness of the material is highly dependent on the striated layers as they offer crack deflection and energy absorption at their interfaces [93,94,96]. The gradual reduction in the thickness of the layers as the radius is increased is clearly evident in Fig.…”

Bio‐Inspired, Smart, Multiscale Interfacial Materials

“…2), such as, the selfcleaning effect of lotus leaves and duck feathers, [34,35] the non-fogging, superhydrophobic compound eyes of mosquitoes, [36] the locomotion of geckos and octopuses via highly adhesive feet and suckers, [37,38] the non-wetting phenomenon of water striders walking on water, [39] the color of peacock feathers, butterfly wings, and beetle shells which is caused by a periodic microstructure, [40][41][42] the special nanostructures causing anti-reflectivity in cicada's wings and moth's compound eyes, [43,44] and lastly the special photonic reflectivity of sponge spurs due to their unique microstructure. [45] All these features are suitable for bio-inspiration.…”

“…Likewise, the special photonic reflectivity of sponge spurs is ascribed to unique microstructure as well. [45] In summary, many unique properties found in nature can be attributed to hierarchical structures. The practical realization of complex functionalities in bio-inspired materials depends on well-ordered, multiscale structures (micro-and macrostructures) produced by various physical and chemical methods, and is a crucial point in the design of novel BSMI materials.…”

Composites, Multifunctional

“…Biomineral composites are composed of an organic matrix of pro teins, lipids and polysaccharides. The structure consist of a nano-or micro-scale amorphous or crystalline minerals formed by a biologically induced or controlled mineraliza tion processes, through complex chemical interactions be tween organic and inorganic matrices [2,42,91,116]. The structure is usually complex with the organic and the mineral components tightly interwoven at the nanoscale level, highly ordered and hierarchical to give high strength, rigidity along with mechanical and chemical stability, that are superior to synthetic materials made from the same materials.…”