Reversible nanoscale local wettability modifications by thermochemical nanolithography

Recently, the development of a versatile thermochemical nanolithography (TCNL) technique was reported. It allows for simultaneous control of the local chemistry and topography of thin polymer films. This technique can pattern sub-15 nm chemical and topographical features at the rate of 1.4 mm per second by inducing thermally-activated chemical reactions by means of a heated atomic force microscope (AFM) tip. TCNL is achievable in different environments and can easily be adapted to a variety of substrates and chemical functionalities. Here, we demonstrate that a thin polymer film can be chemically modified twice using TCNL to tune its wettability. We are able to write hydrophilic nanopatterns over a hydrophobic polymer surface in a first heating step and then revert back to a hydrophobic nanopattern in a second heating step. This capability is particularly useful in data storage application and complex nanofluidic device design.