Micro∕nanoscopic patterning of polymeric materials by atomic force microscope assisted electrohydrodynamic nanolithography

In this work, we address the spatiotemporal evolution of micro∕nanoscopic pattern formation on polymer films by atomic force microscope (AFM) assisted electrohydrodynamic (EHD) nanolithography. This patterning method combines the locality and site specificity of AFM and the surface wave amplification of EHD instability for pattern creation and is capable of generating a series of structures corresponding to the zeroth- to second-order wave patterns. Detailed simulations in the framework of nonlinear three-dimensional analysis are presented to elucidate the localized EHD pattern formation. The experimental and theoretical results are quantitatively compared to address the characteristics of the AFM-assisted EHD pattern formation. The impact of key experimental parameters such as the tip bias voltage and bias duration on the formation rate, morphology, and lateral dimension of the wave patterns are discussed. The AFM assisted EHD nanolithography would open new route to the fabrication of complex polymer nanostructures.