The behavior of 2-(docosylamino)-5-nitropyridine (DCANP) spreading
monolayers was investigated as
a function of temperature, pH, and subphase composition. The
interactions of DCANP monolayers with
copper ions dissolved into the subphase at different concentrations
were also studied. The investigations
were carried out by measuring surface pressure and surface
potential−area isotherms. Langmuir−Blodgett
(LB) films transferred from pure water and copper aqueous subphases
were also studied by Fourier transform
infrared (FTIR), UV−vis, and electron paramagnetic resonance (EPR)
spectroscopies, X-ray photoelectron
spectroscopy (XPS), ellipsometry, and refractive index measurements.
The interactions between copper
ions and DCANP molecules were investigated by means of various
techniques in the bulk phase, in
monolayers, and in LB films. Clear evidence of interactions
between DCANP and copper ions was provided
only from EPR spectroscopy in the LB films, because of the very small
molar ratio of bound/free DCANP
in the LB films. The refractive index of Cu-doped LB films was
shown to be increased by the presence
of metal ions.