Abstract
Organisms use soft confinement structures, such as vesicles and compartments, to direct the nucleation of calcium carbonate (CaCO3) and its subsequent processes during biomineralization. Despite recent efforts elucidating confinement’s effects on CaCO3polymorph selection, we still poorly understand how the size and distribution of CaCO3are controlled within soft confinement. Here, using a size-controlled nanoemulsions system made from isooctane, Span 80, Tween 80, and aqueous solutions, we studied CaCO3formation in soft confinement. Small angle X-ray scattering (SAXS) confirmed that a 72 nm aqueous core in nanoemulsions served as the confined space for CaCO3formation. Unlike the ∼50 nm CaCO3particles that formed in the unconfined solution, small angle neutron scattering (SANS) and transmission electron microscope (TEM) showed that ultrasmall and amorphous calcium carbonate precipitated within soft confinement and did not exhibit any aggregation/coalescence of nanoparticles even after 24 h of reaction.
| Original language | English |
|---|---|
| Pages (from-to) | 8325-8331 |
| Number of pages | 7 |
| Journal | Crystal Growth and Design |
| Volume | 25 |
| Issue number | 20 |
| DOIs | |
| State | Published - Oct 15 2025 |
Funding
This work is supported by the American Chemical Society’s Petroleum Research Fund (62756-ND5). The work is also partially supported by the National Alliance for Water Innovation (NAWI, Project ID 6.21), funded by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE), Industrial Efficiency and Decarbonization Office, under Funding Opportunity Announcement DE-FOA-0001905. The views expressed herein do not necessarily represent the views of the U.S. Department of Energy or the United States Government. The authors would like to acknowledge Washington University’s Institute of Materials Science & Engineering (IMSE) for the use of TEM and Professor James C. Ballard for carefully reviewing the manuscript. This research used resources from the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.