Patterning surfaces using tip-directed displacement and self-assembly

An atomic force microscopy (AFM)-based procedure, a nanopen reader and writer (NPRW), is developed to produce nanometer scale patterns on surfaces. In each NPRW experiment, a self-assembled monolayer serves as the resist, while an AFM tip displaces the resist molecules from desired locations by using a high shear force. The AFM tip is precoated with adsorbate molecules which can adsorb to the newly exposed substrate areas. This procedure combines the advantages of two recently developed AFM lithography methods: nanografting(Xu, S.; Liu, G. Y. Langmuir 1997, 13, 127) and dip-pen nanolithography (Piner, R. D,; Zhu, J.; Xu, F.; Hong, S.; Mirkin, C. A. Science 1999, 283, 661). NPRW is easy to complete and able to produce desired patterns with multiple components. In addition, NPRW can reach high spatial resolution, independent of the texture of the paper and the humidity of the environment. The size and geometry of these nanopatterns are well preserved because the resist molecules efficiently prevent diffusion and smearing.