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Title: Trends in mica–mica adhesion reflect the influence of molecular details on long-range dispersion forces underlying aggregation and coalignment

Here, oriented attachment of nanocrystalline subunits is recognized as a common crystallization pathway that is closely related to formation of nanoparticle superlattices, mesocrystals, and other kinetically stabilized structures. Approaching particles have been observed to rotate to achieve co-alignment while separated by nanometer-scale solvent layers. Little is known about the forces that drive co-alignment, particularly in this “solvent-separated” regime. To obtain a mechanistic understanding of this process, we used atomic force microscopy-based dynamic force spectroscopy with tips fabricated from oriented mica to measure the adhesion forces between mica (001) surfaces in electrolyte solutions as a function of orientation, temperature, electrolyte type, and electrolyte concentration. The results reveal a ~60° periodicity as well as a complex dependence on electrolyte concentration and temperature. A continuum model that considers the competition between electrostatic repulsion and van der Waals attraction, augmented by microscopic details that include surface separation, water structure, ion hydration, and charge regulation at the interface, qualitatively reproduces the observed trends and implies that dispersion forces are responsible for establishing co-alignment in the solvent-separated state.
ORCiD logo [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [1] ;  [4] ;  [1] ;  [4]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Jiaotong Univ., Shaanxi (China)
  3. Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)
  4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Univ. of Washington, Seattle, WA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0027-8424; 49383; 49165; KC0203020
Grant/Contract Number:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 114; Journal Issue: 29; Journal ID: ISSN 0027-8424
National Academy of Sciences, Washington, DC (United States)
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; Environmental Molecular Sciences Laboratory; orientation-dependent interparticle forces; dynamic force spectroscopy; atomic force; microscopy; solvent structure; DLVO theory
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1415084