Nanoscale structural and functional mapping of nacre by scanning probe microscopy techniques.
Nanoscale structural and functional mapping of nacre by scanning probe microscopy techniques.
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DOI：
10.1039/c3nr02731g
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发表时间：
2013-11
期刊：
影响因子：
6.7
通讯作者：
Xilong Zhou;Hongchen Miao;Faxin Li
中科院分区：
文献类型：
--
作者：
Xilong Zhou;Hongchen Miao;Faxin Li
珍珠层由于其纳米级的层次结构和非凡的力学性能而受到极大的关注。同时，珍珠层的纳米压电性能也被研究，但结构与功能的关系从未得到解决。在本工作中，我们首先利用原子力声学显微镜（AFAM）实现了绿色鲍鱼珍珠层的定量纳米力学映射。矿物片的模量被确定为约80 GPa，有机生物聚合物的模量不超过23 GPa，并且有机-无机界面宽度被确定为约34 ± 9 nm。然后，我们进行了AFAM和压电响应力显微镜（PFM）映射在同一扫描区域，探讨纳米力学和压电性能之间的相关性。PFM测试表明，有机生物聚合物表现出比矿物片明显更强的压电响应，并且它们相互渗透，这在人造材料中很难重现。最后，还使用开关光谱PFM观察到的相位磁滞回线和振幅蝶形回线，这意味着珍珠层也可能是一种生物铁电材料。所获得的珍珠层纳米结构和功能特性对于理解其变形机理和设计具有特殊性能的仿生材料具有重要的意义。
Nacre has received great attention due to its nanoscale hierarchical structure and extraordinary mechanical properties. Meanwhile, the nanoscale piezoelectric properties of nacre have also been investigated but the structure-function relationship has never been addressed. In this work, firstly we realized quantitative nanomechanical mapping of nacre of a green abalone using atomic force acoustic microscopy (AFAM). The modulus of the mineral tablets is determined to be ~80 GPa and that of the organic biopolymer no more than 23 GPa, and the organic-inorganic interface width is determined to be about 34 ± 9 nm. Then, we conducted both AFAM and piezoresponse force microscopy (PFM) mapping in the same scanning area to explore the correlations between the nanomechanical and piezoelectric properties. The PFM testing shows that the organic biopolymer exhibits a significantly stronger piezoresponse than the mineral tablets, and they permeate each other, which is very difficult to reproduce in artificial materials. Finally, the phase hysteresis loops and amplitude butterfly loops were also observed using switching spectroscopy PFM, implying that nacre may also be a bio-ferroelectric material. The obtained nanoscale structural and functional properties of nacre could be very helpful in understanding its deformation mechanism and designing biomimetic materials of extraordinary properties.