Toward the Chemistry of Carboxylic Single-Walled Carbon Nanotubes by Chemical Force Microscopy

Abstract

The present article describes the immobilization of chemically shortened single-walled carbon nanotubes (SWNTs) onto atomic force microscopy (AFM) tips using a novel wet chemistry procedure. Preliminary results on the measurement of dissociation properties of carboxylic acid groups at the open end of the shortened SWNTs in aqueous solution by chemical force microscopy (CFM) are also described. The as-prepared long SWNTs were cut into short tubes by chemical oxidation, which produced −COOH groups at the open ends of the tubes. The shortened SWNTs were covalently attached to AFM tips by surface condensation between AFM tips modified with primary amino-terminated self-assembled monolayers (SAMs) and the carboxylic groups at the exposed end of the tube. The nanotube orientation on the AFM tips was demonstrated using AFM force calibration mode. The dissociation properties of carboxylic groups at the end of SWNTs were investigated by measuring the adhesion force between SWNTs modified AFM tips and hydroxyl-term...