Two new approaches for patterning polymer films using templates prepared by microcontact printing

Abstract

Two new methods for preparing micron-scale patterns of hyperbranched polymer films are reported. Both approaches rely on passivation of a reactive surface by microcontact printing (μ-CP) followed by polymer grafting to unpassivated regions of the surface. The first method involves patterning of a hyperbranched polymer composite film containing poly(amidoamine) dendrimers and Gantrez (an active anhydride copolymer) onto Au. These structures are prepared by partial passivation of an Au surface with an n-hexadecanethiol self-assembled monolayer (SAM) using μ-CP, followed by multiple covalent grafting iterations of the dendrimer/Gantrez polymer film onto the unpassivated regions. The second patterning method involves partial passivation of an activated mercaptoundecanoic acid (MUA) SAM, followed by modification of the unpassivated SAM with a layered poly(acrylic acid)/poly(ethylene glycol) (PAA/PEG) nanocomposite. The approach for fabricating these structures consists of formation of an activated MUA SAM, μ-CP of n-hexadecylamine (C16NH₂) to partially passivate the MUA SAM, and sequential covalent grafting of PAA and then PEG onto the unpassivated regions. Ellipsometry, Fourier transform infrared−external reflection spectroscopy (FTIR-ERS), optical microscopy, and tapping-mode atomic force microscopy (TM-AFM) provide evidence for the viability of these methods. For both types of films, lines of polymer having lateral dimensions of ∼20 μm and edge resolutions of <1 μm are obtained. The polymer thicknesses are on the order of 20−50 nm depending on the number of iterative polymer grafting steps.