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Title: Direct determination of the local Hamaker constant of inorganic surfaces based on scanning force microscopy

The energetics involved in the bonding fluctuations between nanometer-sized silicon dioxide (SiO{sub 2}) probes and highly oriented pyrolytic graphite (HOPG) and molybdenum disulfide (MoS{sub 2}) could be quantified directly and locally on the submicron scale via a time-temperature superposition analysis of the lateral forces between scanning force microscopy silicon dioxide probes and inorganic sample surfaces. The so-called “intrinsic friction analysis” (IFA) provided direct access to the Hamaker constants for HOPG and MoS{sub 2}, as well as the control sample, calcium fluoride (CaF{sub 2}). The use of scanning probe enables nanoscopic analysis of bonding fluctuations, thereby overcoming challenges associated with larger scale inhomogeneity and surface roughness common to conventional techniques used to determine surface free energies and dielectric properties. A complementary numerical analysis based on optical and electron energy loss spectroscopy and the Lifshitz quantum electrodynamic theory of van der Waals interactions is provided and confirms quantitatively the IFA results.
Authors:
; ;  [1]
  1. Department of Chemical Engineering, University of Washington, Seattle, Washington 98195-1750 (United States)
Publication Date:
OSTI Identifier:
22310767
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BONDING; CALCIUM FLUORIDES; CONTROL; DIELECTRIC PROPERTIES; ELECTRONS; ENERGY-LOSS SPECTROSCOPY; FLUCTUATIONS; GRAPHITE; INTERACTIONS; MICROSCOPY; MOLYBDENUM SULFIDES; NUMERICAL ANALYSIS; SILICA; SILICON OXIDES; SURFACES; VAN DER WAALS FORCES