Characterization of surface forces via atomic force microscopy

The accepted theory that reconciles attractive and repulsive forces has become known as the Deryaguin-Landau-Verwey-Overbeek (DLVO) theory and may be simply stated as VS = VC + VA + V R, where VS is the total potential, VC is the core repulsive potential due to Pauli exclusion, VA is the Van der Waals attractive potential, and VR is the double-layer repulsive potential. The DLVO theory is widely regarded as a cornerstone for understanding colloidal systems and forces on the molecular scale.; The objective of this study is the characterization of forces between two surfaces using an atomic force microscope (AFM). Quantitative investigations have been made using an AFM of surfaces forces present between standard Si 3N4 tips and mica substrates in air, water, ethanol, and hexane. Silica spherical probes have been used to investigate the nature of forces over Si, mica, and aminopropyltriethoxysilane coated mica.; Modeling of selected data has yielded results consistent with the expected behavior of the Casimir effect. Additionally, phenomenon previously unreported in the literature for similar AFM investigations is presented.