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Forces between Surfactant‐Coated ZnS Nanoparticles in Dodecane: Effect of Water
Author(s) -
Godfrey Alig A. R.,
Akbulut M.,
Golan Y.,
Israelachvili J.
Publication year - 2006
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200500705
Subject(s) - mica , materials science , nanoparticle , dodecane , colloid , pulmonary surfactant , adsorption , chemical engineering , nanotechnology , capillary action , suspension (topology) , chemical physics , composite material , chemistry , organic chemistry , mathematics , homotopy , pure mathematics , engineering
The forces between mica surfaces confining solutions of spherical and rod‐shaped ZnS nanoparticles (diameter ca. 5 nm) coated with hexadecylamine or octadecylamine surfactant in dodecane have been measured in the absence and after the introduction of trace amounts of water. Initially, or at very low water content, the water molecules cause the nanoparticles to aggregate and adsorb on the hydrophilic mica surfaces, resulting in a long‐range exponentially decaying repulsive force between the surfaces. After longer times (> 20 h), water bridges nucleate and grow between the nanoparticles and mica surfaces, and attractive capillary forces then cause a long‐range attraction and a strong (short‐range) adhesion. It is found, as has previously been observed in nonaqueous bulk colloidal systems, that even trace amounts of water have a profound effect on the interactions and structure of nanoparticle assemblies in thin films, which in turn affect their physical properties. These effects should be considered in the design of thin‐film processing methodologies.