Composite monolayers of cadmium stearate and polyaniline processed wit
h camphor sulphonic acid have been obtained at the air-water interface
and subsequently transferred onto substrates as uniform Langmuir-Blod
gett multilayers. Pressure-area (Pi-A) isotherm studies indicated that
polyaniline molecules are not squeezed out of the cadmium stearate ma
trix during compression or in the compressed state. Monolayer stabilit
y is seen to decrease when the polymer content is increased beyond 60%
(in weight) which is probably associated with the formation of microa
ggregates that also affected the monolayer surface potential at large
areas per molecule. With increasing amount of polyaniline in the mixtu
re, a transition from Y-type to Z-type deposition has been observed. T
ransferred multilayer LB films were characterized by UV-vis, FTIR, XRD
, surface potential, and de electrical conductivity measurements. UV-v
is results indicated that though the polyaniline was in the doped stat
e in the spreading solution, the transferred films were in the emerald
ine base state. FTIR studies revealed that the transferred films mainl
y contained cadmium stearate salt in addition to polyaniline. XRD resu
lts indicated that the stacking order is dependent on the polyaniline
content in the composite films, the order was found to decrease upon i
ncreasing the polymer amount. The uniformity of transferred films was
confirmed by surface potential studies. A possible packing arrangement
in these composite Langmuir and Langmuir-Blodgett films has been prop
osed. (C) 1998 Elsevier Science Limited.