Preparation of Different Poly 3-Alkylthiophene Ultrathin Films at the Surface of Chemically Adsorbed Monolayer Having Thienyl Group

Abstract

Polymerization processes of two types ultrathin films containing polythienyl groups anchored to the substrate surface through siloxane bonds were investigated. When the oxidative polymerization on the Chemically Adsorbed (CA) monolayer prepared with 11-(3-thienylundecyl)trichlorosilane (TTS) was performed in the acetonitrile solution containing 3-octylthiophene monomer and FeCl₃, the thienyl groups in the CA monolayer and the outer 3-octylthiophene monomers were polymerized each other along the directions of both in-plane and out-of-plane of the CA monolayer. On the other hand, when the oxidative polymerization was performed without the additive 3-octylthiophene monomer, the long conjugated linkage of the thienyl groups was not formed in the CA monolayer. The highest conductivity of the film prepared with the additive 3-octylthiophene of about 10 nm thickness was 10⁻² S/cm.

Keywords:

• Monolayer
• 3-octylthiophene
• oxidative polymerization
• polythiophene
• self-assembled

Acknowledgments

The authors wish to thank Mr. Shinya Bito of Department of Advanced Materials Science, Faculty of Engineering, Kagawa University, for his experimental works and helpful comments. The authors also thank Mr. Ken Kitashouji, Predisent of NADO Institute, Ltd., for his synthesis and supplying the thienyl system CA reagents.