2 research outputs found
Atomic Force Microscopy (AFM)-Based Nanografting for the Study of Self-Assembled Monolayer Formation of Organophosphonic Acids on Al<sub>2</sub>O<sub>3</sub> Single-Crystal Surfaces
Adsorption, stability, and organization kinetics of organophosphonic
acids on single-crystalline alumina surfaces were investigated by
means of atomic force microscopy (AFM)-based imaging, nanoshaving,
and nanografting. AFM friction and phase imaging have shown that chemical
etching and subsequent annealing led to heterogeneities on single-crystalline
surfaces with (0001) orientation. Self-assembly and stability of octadecylphosphonic
acid (ODPA) were shown to be strictly dependent upon the observed
heterogeneities of the surface termination, where it was locally shown
that ODPA can loosely or strongly bind on different terminations of
the crystal surface. Organization kinetics of ODPA was monitored with
nanografting on (0001) surfaces. Supported by measurements of surface
wettability and diffuse reflectance infrared Fourier transform spectroscopy
(DRIFTS), it was demonstrated that the lack of organization within
the protective adsorbed hexylphosphonic acid (HPA) monolayer on alumina
surfaces facilitated the reduced confinement effect during nanografting,
such that kinetics information on the organization process of ODPA
could be obtained