Structured Polymer Brushes by AFM Lithography

An alternative approach to obtain structured polymer brushes by mechanical nano-scratching with atomic force microscopy (AFM) lithography, was reported. It was observed that site-selective immobilization of functionalized materials like dyes into these structured polymer brushes can be achieved. The thin films of brush polymers were prepared using NMP on oxidized Si wafers containing a 300-nm oxide layer. Immobilization of the polymerization initiators was carried out using transsilyletherification on the oxidized Si wafer. Surface-initiated radical polymerization (SIP) was carried out by placing the initiator-covered wafer into neat styrene or neat n-butyl acrylate in the presence of sacrificial alkoxyamine. It was observed that polymer brushes with a thickness of 20-30nm can be structured and scratched down to the substrate with single scan lines without dragging of material.