Department of Mechanical Engineering, McGill University, Montreal, QC, Canada.
Bioinspir Biomim. 2010 Sep;5(3):035001. doi: 10.1088/1748-3182/5/3/035001. Epub 2010 Aug 20.
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.
珍珠母是大量软体动物贝壳内的虹彩层。这种天然复合材料的矿物质含量非常高，这使得它坚硬而结实。然而，珍珠母最令人印象深刻的是其韧性：它比组成它的矿物质韧性高出三个数量级。没有任何人造复合材料能够如此显著地提高韧性，因此珍珠母已成为仿生模型材料。珍珠母中的矿物质呈微观多角形薄片形式，当材料受到拉伸时，这些薄片能够大量相互“滑动”。这种关键的机制使珍珠母成为一种准韧性材料，从而大大提高了其韧性并使其具有耐损伤性。过去曾开发出许多“人工珍珠母”，但没有一种能够真正复制薄片滑动的显著机制。在这项工作中，珍珠母的选定结构特征被应用于基于 PMMA 的复合材料中，该复合材料首次能够复制集体薄片滑动机制。这种材料表明，在天然珍珠母中起作用的强大增韧机制可以在工程材料中被复制和利用。
