Atomic force microscopy is an imaging tool used widely in fundamental research,
although it has, like other scanned probe microscopies, provided only limited information
about the chemical nature of systems studied. Modification of force
microscope probe tips by covalent linking of organic monolayers that terminate
in well-defined functional groups enables direct probing of molecular interactions
and imaging with chemical sensitivity. This new chemical force microscopy
technique has been used to probe adhesion and frictional forces between distinct
chemical groups in organic and aqueous solvents. Contact mechanics provide a
framework to model the adhesive forces and to estimate the number of interacting
molecular groups. In general, measured adhesive and frictional forces follow
trends expected from the strengths of the molecular interactions, although solvation
also plays an important role. Knowledge of these forces provides a basis
for rationally interpretable mapping of a variety of chemical functionalities and processes such as protonation and ionization.[ 来自科研家族 晶体材料家族 ]

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