Mixed monolayers of a new chiral amino acid porphyrin (Py) and arachidic ac
id (AA) at the air/water interface were studied The diagrams obtained by pl
otting the mean area per molecule as a function of molar fraction of Py sho
wed positive deviations from ideal conditions at Low surface pressure (pi)
such as pi = 5 and 15 mN m(-1) and showed ideal miscible behavior at high s
urface pressures, such as pi = 25 mN m(-1). Vertical uniformity of the mixe
d LB films was demonstrated by UV-visible and fluorescence spectra. Aggrega
tes were present when the mixed him was transferred at various surface pres
sures and at different molar ratios of Py and AA. When the molar ratio of P
y was increased from 0.05 to 1.00, the absorption peak of the Soret band ba
thochromically shifted ca. 5.3 nm. When the deposited pressure is increased
from 5 to 30 mN m(-1), the absorption peak of Soret band of 1:4 Py-AA mixe
d LB film bathochromically shifted ca. 3.7 nm, and the absorbance increased
linearly. Low angle X-ray diffraction results showed that the mixed LB fil
ms had a periodic layer structure with a layer spacing of ca. 5.5 nm. (C) 2
000 Elsevier Science B.V. All lights reserved.