June 19, 2019
Journal Article

Direct observation of mineral-organic composite formation reveals occlusion mechanism

Kang Cho
Yi-Yeoun Kim
Pengcheng Yang
Alexander Kulak
Jolene Lau
Prashant Kulshreshtha
Steven Armes
Fiona Meldrum
Jim De Yoreo
Wei Cai
Haihua Pan
Manipulation of inorganic materials with organic macromolecules enables organisms to create biominerals such as bones and seashells, where occlusion of biomacro-molecules within individual crystals generates superior mechanical properties. Current understanding of this process comes from entrapment of micron-size particles in cooling melts. Here, by studying micelle incorporation in calcite with atomic force microscopy and micromechanical simulations, we show that different mechanisms govern nanoscale occlusion. By simultaneously visualizing the micelles and propagating step edges, we demonstrate that the micelles experience significant compression during occlusion, which is accompanied by cavity formation. This generates local lattice strain, leading to enhanced mechanical properties. These results give new insight into the formation of occlusions in natural and synthetic crystals, and will facilitate the synthesis of multifunctional nanocomposite crystals.

Revised: June 19, 2019 | Published: January 6, 2016

Cho K., Y. Kim, P. Yang, W. Cai, H. Pan, A.N. Kulak, and J.L. Lau, et al. 2016. "Direct observation of mineral-organic composite formation reveals occlusion mechanism." Nature Communications 7. PNNL-SA-114998. doi:10.1038/ncomms10187