Imaging Of Hierarchically Structured Materials

Sarıkaya, Mehmet; Aksay, İlhan A.

doi:10.1557/proc-255-293

Cited by 11 publications

(3 citation statements)

References 16 publications

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“…For a long time, the tablets were believed to be composed of a few twinned microscopic crystals [15]. However, recent studies using atomic force microscopy revealed that the tablets are in fact composed of nanograins with a consistent crystallographic texture and separated by a fine network of organic materials [16,17].…”

Section: The Structure Of Nacrementioning

confidence: 99%

Nacre from mollusk shells: a model for high-performance structural materials

2010

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Nacre is the iridescent layer found inside a large number of mollusk shells. This natural composite has a very high mineral content, which makes it hard and stiff. However it is the toughness of nacre which is the most impressive: it is three orders of magnitude tougher than the mineral it is made of. No manmade composite material can boast such amplification in toughness, and for this reason nacre has become a biomimetic model material. The mineral in nacre comes in the form of microscopic polygonal tablets, which have the ability to 'slide' on one another in large numbers when the material is loaded in tension. This key mechanism makes nacre a quasi-ductile material, which in turn greatly increases its toughness and makes it damage tolerant. Numerous 'artificial nacres' were developed in the past but none of them can truly duplicate the remarkable mechanism of tablet sliding. In this work selected structural features of nacre were implemented in a PMMA-based composite, which for the first time could replicate the collective tablet sliding mechanism. This material demonstrates that the powerful toughening mechanism operating in natural nacre can be duplicated and harnessed in engineering materials.

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Section: The Structure Of Nacrementioning

confidence: 99%

Nacre from mollusk shells: a model for high-performance structural materials

2010

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“…Although the mechanisms of biomineralization are not yet completely understood, it is hoped that they may provide new models for the fabrication of advanced materials − and give new insights into the genetic control of biological structure . Biomineralized composite materials typically contain only a few weight percent of proteins or other biopolymers, yet these macromolecules direct the assembly of elaborately structured composites with remarkable precision over scales ranging from the atomic to macroscopic. ,− ,− …”

Section: Introductionmentioning

confidence: 99%

Does Abalone Nacre Form by Heteroepitaxial Nucleation or by Growth through Mineral Bridges?

et al. 1997

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We present experimental support for a model of abalone nacre growth that is based on mineral bridges between successive aragonite tablets rather than on heteroepitaxial nucleation. Interlamellar sheets of organic polymers delineate the aragonite tablets but allow the tablets to grow mineral bridges through pores in the sheets. Atomic force microscope images of interlamellar organic sheets from flat pearls made by Haliotis rufescens (red abalone; marine gastropod mollusk) reveal a fibrous core and holes of 5-50 nm in diameter. Scanning ion conductance microscopy shows that these holes are actually pores through the interlamellar sheets. With the help of statistical analysis we can associate the pore-to-pore spacings in the interlamellar sheets with the observed offsets of successive nacre tablets. These results, supplemented by AFM, SEM, and TEM images, support and extend the model of biofabrication of gastropod nacre which is based on mineral bridges between the aragonite tablets.(in the aragonite polymorph) and proteins, exhibiting exceptional regularity and mechanical strength. 1,2,[18][19][20][21][22][23][24][25][26][27][28][29][30] The interdigitating brickwork array of crystals and

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“…sliding of bricks and so on [19,20]. These findings not only shed light on the origin of the high strength and high toughness in the nacreous materials, but also would be of great value to the design and fabrication of nacreous biomimetic materials.…”

Section: Advanced Composites For Marine Engineeringmentioning

confidence: 71%

Crack-Induced Stress Concentration Is Suppressed in Nacreous Composites

Yao

2015

MSF

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Linear elastic fracture mechanics (LEFM) indicates that crack-like flaws tend to intensify stress in brittle materials with stress intensity proportional to the square root of the crack size. Under given loading, monolithic brittle materials can only endure cracks smaller than a critical size. In this paper, however, our exploration into the stress state of nacreous composites shows that the crack-induced stress intensification/concentration and its dependence on crack size can be suppressed in composites with ‘brick-and-mortar’ structure. This feature can be attributed to the unique ‘brick-and-mortar’ (B-and-M) structure and the complementary dissimilarity between ‘brick’ (e.g. minerals) and ‘mortar’ (e.g. proteins) phases in mechanical properties. Our findings provide a profound insight into the origin of high strength and high toughness in nacreous composites.

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Imaging Of Hierarchically Structured Materials

Cited by 11 publications

References 16 publications

Nacre from mollusk shells: a model for high-performance structural materials

Nacre from mollusk shells: a model for high-performance structural materials

Does Abalone Nacre Form by Heteroepitaxial Nucleation or by Growth through Mineral Bridges?

Crack-Induced Stress Concentration Is Suppressed in Nacreous Composites

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