US Patent 7491422 - Dip pen nanolithography with polymer coated tip

http://www.freepatentsonline.com/7491422.html

This patent from Nanoink teaches improvements in Dip Pen Nanolithography that enhance the tip lifespan and increase the diffusion rate leading to higher speed processing.
Claim 1 reads:

1. A method of direct-write nanolithography comprising:

transporting an ink from a polymer-coated nanoscopic tip to a substrate to form a structure on the substrate,

wherein the ink comprises solvent and the structure comprises internal hollows from direct transfer of the solvent to the substrate,

wherein polymer adheres to the tip and is not transported to the substrate, and wherein the polymer is a hydrophobic elastomeric polymer having a glass transition temperature of about 25° C. or less.