The wettability of a thin polymer film was modified twice by thermochemical nanolithography. By means of a first local chemical modification induced by an atomic force microscope tip heated to , hydrophilic patterns are written over an originally hydrophobic polymer surface. By further heating to , a second chemical modification reverses the local wettability change introduced by the first chemical modification. This write-read-overwrite capability can be particularly useful in the design of complex nanofluidic devices.
REFERENCES
The thermal cantilevers used in this study have a normal spring constant of about . We have used the same thermal cantilever for the friction measurements both on the macroscopically treated samples and on the locally tip-treated samples.