Abstract
Although interfacial solution structure impacts environmental, biological, and technological phenomena, including colloidal stability, protein assembly, heterogeneous nucleation, and water desalination, its molecular details remain poorly understood. Here, we visualize the three-dimensional (3D) hydration structure at the boehmite(010)-water interface using fast force mapping (FFM). Using a self-consistent scheme to decouple long-range tip-sample interactions from short-range solvation forces, we obtain the solution structure with lattice resolution. The results are benchmarked against molecular dynamics simulations that explicitly include the effects of the tip with different levels of approximation and systematically account for tip size, chemistry, and confinement effects. We find four laterally structured water layers within 1 nm of the surface, with the highest water densities at sites adjacent to hydroxyl groups. The key features beyond the first two layers can only be predicted using a full-scale simulation of the boehmite-water-silica system. Our findings further reveal a complex relationship between site-specific chemistry, water density, and long-range particle interactions; and present important advances toward quantitative data interpretation in 3D FFM.
| Original language | English |
|---|---|
| Pages (from-to) | 1282-1291 |
| Number of pages | 10 |
| Journal | Journal of Physical Chemistry C |
| Volume | 125 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 21 2021 |
Funding
Design of the study, collection, and analysis of three dimensional fast force mapping (3D FFM) data, MD analysis of interactions between a Leonard-Jones object and boehmite, and integration of all measurements and simulations were supported as part of IDREAM (Interfacial Dynamics in Radioactive Environments and Materials), an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science (SC), Office of Basic Energy Sciences (BES). Development of the 3D FFM analysis and visualization capability was supported by the Laboratory Directed Research and Development Program (LDRD) at Pacific Northwest National Laboratory (PNNL) through the Linus Pauling Distinguished Postdoctoral Fellowship program to which E.N. is grateful for support. Incorporation of the concepts of nanoscale hydrodynamics was supported by the LDRD Program at PNNL. Development of the 3D FFM measurement capability was carried out at PNNL with support from the BES Division of Materials Science and Engineering, Synthesis and Processing Sciences Program. Development of concepts for and analyses of long-range forces was carried out at PNNL with support from the BES Chemical Sciences, Geosciences, and Biosciences Division (CGSB), Chemical Physics and Interfacial Sciences Program. The design and execution of the MD simulations of the boehmite–water–silica system were carried out at PNNL with support from the BES, CGSB, Geosciences Program. These simulations were performed using PNNL Institutional Computing and the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the U.S. DOE’s Office of Biological and Environmental Research and located at PNNL. PNNL is a multiprogram national laboratory operated for DOE by Battelle Memorial Institute under contract no. DE-AC05-76RL0-1830.
