The study of self-assembled monolayer surfaces prepared by microcontact printing methods using adhesive force mapping in water

H. Okui, Fuminobu Sato, U. Akiba, K. Suga, and M. Fujihira

Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan

In the present work, we applied chemical force microscopy (CFM) by mapping adhesive force using pulsed-force-mode atomic force microscopy (PFM-AFM) with chemically modified AFM tips [1] to study mixing of two components in patterned self-assembled monolayers (SAMs). The patterned SAMs were prepared by two types of microcontact printing methods. One is the wet-inking method, in which inking of the stamp was done by placing a thiol ethanol solution on it and then removing the excess solution under a stream of nitrogen. The other is the contact-inking method, in which an inker pad made of polydimetylsiloxane (PDMS) was dipped in a thiol ethanol solution overnight, then the excess solution was removed by a stream of nitrogen, and finally the stamp was placed on the inker pad impregnated with the thiol solution. Contamination due to vapor phase transfer during stamping and defects in printed areas due to insufficient ink transfer were studied by the present CFM in water.

1) M. Fujihira, M. Furugori, U. Akiba, and Y. Tani, Ultramicroscopy 86, 75 (2001).