Bi. Seo et al., HYDRATION NUMBER OF CALCIUM PALMITATE LB FILM DEPOSITED ON A PIEZOELECTRIC QUARTZ-CRYSTAL PLATE, Thin solid films, 329, 1998, pp. 722-725
The calcium palmitate monolayer formed from palmitic acid on calcium-c
ontaining substrate can be examined regarding the study of hydration b
y applying the quartz crystal microbalance (QCM) technique. Monolayers
of calcium palmitate were deposited on piezoelectric crystal plate by
the Langmuir-Blodgett (LB) technique. Analysis of complete conversion
to calcium palmitate was performed by identification of its infrared
spectra. The estimation of the hydration for the multilayered calcium
palmitate is compared with the data of the multilayered calcium steara
te in the literature. The QCM measurement for determining hydration nu
mber is based on the results of McCaffrey, particularly employed in th
e treatment of drying in vacuum (R.R. McCaffrey, S. Bruckenstein, P.N.
Prasad, Langmuir 2 (1986) 228). In our experiments, the frequency cha
nge of the oscillating quartz transducer for the skimmed calcium palmi
tate also increased after drying in vacuum. Hydration behavior of the
multilayered calcium palmitate LB film is discussed, and it was shown
that the hydration of calcium palmitate exists as monohydrate, though
its hydrophobicity is relatively a little low compared with that of ca
lcium stearate, which has a longer hydrocarbon chain length. (C) 1998
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