Direct conversion of Teflon into nanodiamond films

Abstract

We report a novel nonequilibrium approach for direct laser writing diamond by melting amorphous polytetrafluoroethylene (PTFE:(C2F4) n) in ambient conditions. The nanosecond laser pulses disintegrate PTFE, forming the undercooled molten carbon. This undercooled molten carbon regrows into diamond during the ultrafast melt quenching process, which lasts for ∼100 ns. HRTEM imaging, SAED, Raman, and EEL spectroscopy investigations confirm the first-order phase transformation of PTFE into single-crystalline <110> oriented diamond, which is associated with ultrafast unseeded crystallization. Our experimental findings open up a new pathway for the selective conversion of organic polymers into nano and microdiamonds and thin films with laser-writing.