Mk. Ram et al., EFFECT OF ANNEALING ON PHYSICAL-PROPERTIES OF CONDUCTING POLY(ORTHO-ANISIDINE) LANGMUIR-BLODGETT-FILMS, Thin solid films, 302(1-2), 1997, pp. 89-97
Langmuir-Blodgett (LB) films of poly(ortho-anisidine) (POAS) have been
fabricated at pH 1 of the subphase, where the doping during the monol
ayer formation is essential for high quality of the ultrathin films. P
OAS LB films have been systematically characterized using low-angle X-
ray diffraction, UV-Vis and FTIR spectroscopic, current-voltage and ca
pacitance-frequency measurements, respectively. The effect of annealin
g on the physical properties of POAS LB films has been studied as a fu
nction of temperature (from 60 to 150 degrees C). It has been shown th
at annealing causes changes in structural, optical and electrical char
acteristics of POAS LB films. The decrease in thickness (from 24 to 18
.1 Angstrom) of each monolayer of POAS film has been observed for anne
aling at 150 degrees C. The value of conductivity of POAS LB film has
been shown to be varying from 0.4 to 10(-8) S cm(-1) as a function of
annealing temperature. The continuous shift of the UV absorption bands
from 840 to 590 nm with annealing temperature is arising due to the s
imultaneous change of charge defects in POAS LB films. Differential sc
anning calorimetry studies show a complete evaporation of dopant ions
occurring at 180 degrees C in the powder form of POAS, whereas complet
e removal of dopants ions for LB films have been observed for annealin
g at 150 degrees C. The Cole-Cole plot obtained at 80 degrees C for PO
AS LB film shows a mark deviation from a semicircle which indicates th
e operation of complex behaviour in the POAS LB films. It also shows t
he typical behaviour of interfacial polarization caused by the contact
effect of POAS LB firms with chromium metal of interdigited electrode
s for annealing at 150 degrees C. (C) 1997 Elsevier Science S.A.