Preparation of Functional Alternating Polymer Brushes and Their Orthogonal Surface Modification through Microcontact Printing

This paper reports microcontact printing (CP) to immobilize an alkoxyamine initiator (regulator) on glass and silicon substrates and subsequent surface-initiated alternating nitroxide-mediated copolymerization (siNMP) of hexafluoroisopropyl acrylate (HFIPA) and 7-octenylvinyl ether (OVE). The resulting patterned polymer brushes are analyzed by using atomic force microscopy (AFM). In addition, site-specific post-functionalization of the alternating polymer brushes by applying two orthogonal surface reactions is achieved with thiols and amines through CP. The versatility of this post-polymerization modification approach is demonstrated by site-selective immobilization of small organic molecules, fluorophores, and ligands providing a binary bioactive surface. The successful side-by-side orthogonal immobilization is verified by using X-ray photoelectron spectroscopy (XPS) and fluorescence microscopy.