ATOMIC-FORCE MICROSCOPY IMAGES OBTAINED WITH C-60 MODIFIED TIPS

We prepared thioacetate derivatives of C-60 for studying tip-substrate interactions in farce microscopy. They are expected to make ideal hyd rophobic surfaces over tips that are covered with thin gold films, Com pound (1) has two attaching points by short chain to minimize damping of forces that is expected to be distinct in the case of long chain mo lecules, while compound (2) is only one attaching point with a long ch ain. Adsorption kinetics studies by microgravimetry using a quartz cry stal microbalance and by contact angle measurements were performed to confirm chemisorption of the prepared compounds. Topographic images of highly oriented pyrolytic graphite attained using tips coated with th ese compounds do not show deterioration in resolution compared with im ages obtained using bare tips. On comparing force-distance curves, com pound (2) showed a possibility to be advantageous for force measuremen t experiments because surfaces covered with compound (2)were found to be more hydrophobic than others. (C) 1996 American Vacuum Society.