2D laser lithography on silicon substrates via photoinduced copper-mediated radical polymerization

A 2D laser lithography protocol for controlled grafting of polymer brushes in a single-step is presented. A series of polyacrylates were grafted from silicon substrates via laser-induced copper-mediated radical polymerization. Film thicknesses up to 39 nm were reached within 125 mu s of exposure to UV laser light (351 nm). Successful block copolymerization underpinned the controlled nature of the grafting methodology. The resolution of a small structure of grafted PHEA reached 270 mu m and was limited by the type of laser used in the study. Further, a checkerboard pattern of PtBA and POEGA was produced and imaged via time-of-flight secondary ion mass spectrometry (ToF-SIMS), and X-ray photoelectron spectroscopy (XPS).