期刊
ACS NANO
卷 11, 期 7, 页码 6612-6622出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsnano.7b00127
关键词
Ion attachment; crystallization by particle attachment; CPA; biomineralization; PEEM; PIC-mapping; mesocrystal
类别
资金
- Israel Science Foundation [312/15]
- United States-Israel Binational Science Foundation [BSF-2014035]
- U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division [DE-FG02-07ER15899]
- NSF [DMR-1603192]
- US-Israel Binational Science Foundation [BSF-2010065]
- [DE-AC02-05CH11231]
- Division Of Materials Research
- Direct For Mathematical & Physical Scien [1603192] Funding Source: National Science Foundation
Coral skeletons were long assumed to have a spherulitic structure, that is, a radial distribution of acicular aragonite (CaCO3) crystals with their c-axes radiating from series of points, termed centers of calcification (CoCs). This assumption was based on morphology alone, not on crystallography. Here we measure the orientation of crystals and nanocrystals and confirm that corals grow their skeletons in bundles of aragonite crystals, with their taxes and long axes oriented radially and at an angle from the CoCs, thus precisely as expected for feather-like or plumose spherulites. Furthermore, we find that in both synthetic and coral aragonite spherulites at the nanoscale adjacent crystals have similar but not identical orientations, thus demonstrating by direct observation that even at nanoscale the mechanism of spherulite formation is non-crystallographic branching (NCB), as predicted by theory. Finally, synthetic aragonite spherulites and coral skeletons have similar angle spreads, and angular distances of adjacent crystals, further confirming that coral skeletons are spherulites. This is important because aragonite grows anisotropically, 10 times faster along the c-axis than along the a-axis direction, and spherulites fill space with crystals growing almost exclusively along the c-axis, thus they can fill space faster than any other aragonite growth geometry, and create isotropic materials from anisotropic crystals. Greater space filling rate and isotropic mechanical behavior are key to the skeleton's supporting function and therefore to its evolutionary success. In this sense, spherulitic growth is Nature's 3D printing.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据