On the Langmuir-Blodgett transfer of copper tetra-tert-butyl phthalocyanine monolayers in the presence of arachidic acid

This study investigated the influence of arachidic acid as a transfer promoter on the deposition of multilayer copper tetra-tert-butyl phthalocyanine (CuTTBPc) Langmuir-Blodgett (L-B) films on both hydrophilic glass and hydrophobic silanized-glass substrates. With the addition of arachidic acid in a CuTTBPc monolayer at the air/water interface, two transitions corresponding to monolayer collapse were observed in the surface pressure-area isotherm. However, the added arachidic acid had no effect on area relaxation of a CuTTBPc monolayer at 20 mN m(-1). The up-stroke L-B transfer of a CuTTBPc monolayer at 20 mN m(-1) onto a glass substrate was perfect with a transfer ratio of 1.0, but most of the deposited film respread onto the interface during the following down-stroke deposition. It appears that the addition of arachidic acid with a molar fraction of 0.5 caused insignificant influence on the continuous L-B deposition of CuTTBPc films on glass substrates. On a silanized-glass substrate, imperfect Y-type multilayer CuTTBPc L-B films could be fabricated with transfer ratios around 0.5. The presence of arachidic acid in a CuTTBPc monolayer may considerably improve the down-stroke first layer deposition with a transfer ratio close to one. Moreover, the following up-stroke deposition quality of the L-B films was strongly affected by the molar fraction of arachidic acid. (C) 2002 Elsevier Science B.V. All rights reserved.