title: Direct observation of mineral-organic composite formation reveals occlusion mechanism.
abstract: Manipulation of inorganic materials with organic macromolecules enables organisms to create biominerals such as bones and seashells, where occlusion of biomacromolecules within individual crystals generates superior mechanical properties. Current understanding of this process largely comes from studying the entrapment of micron-size particles in cooling melts. Here, by investigating 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.
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Bioscience and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: Kang
authors.initials: K
authors.lastname: Rae Cho
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Yi-Yeoun
authors.identifier: http://orcid.org/0000-0002-8503-4554
authors.initials: YY
authors.lastname: Kim
authors.affiliation: Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Yang
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Cai
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
authors.forename: Haihua
authors.initials: H
authors.lastname: Pan
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Kulak
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Jolene L
authors.initials: JL
authors.lastname: Lau
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Prashant
authors.initials: P
authors.lastname: Kulshreshtha
authors.affiliation: Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Armes
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Fiona C
authors.initials: FC
authors.lastname: Meldrum
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: De Yoreo
mesh_terms: D000327:Adsorption; D002119:Calcium Carbonate / Q000737:chemistry*; D003460:Crystallization; D008823:Micelles; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D015394:Molecular Structure; D053761:Nanocomposites / Q000737:chemistry; D011108:Polymers / Q000737:chemistry
chemical_list: D008823:Micelles; D011108:Polymers; D002119:Calcium Carbonate