Two-step local functionalization of fluoropolymer Dyneon THV microfluidic materials by scanning electrochemical microscopy combined to click reaction

We propose an original two-step strategy combining the use of scanning electrochemical microscopy (SECM) and molecular chemistry via a “click” reaction (copper (I)-catalyzed azide alkyne cycloaddition (CuAAC)) to locally functionalize Dyneon THV surfaces, an attractive fluoropolymer for microfluidic applications. The first step consists in the local reduction of THV using a SECM tip to activate the surface by the creation of a locally carbonized zone and notably the formation of surface alkyne functions. This is then followed by a direct CuAAC reaction with an azide-bearing ligand for its local immobilization. The proof of concept is demonstrated by efficient local functionalization of the substrate with a fluorescent dye stable up to 6 months. Surface modifications were characterized by IR-ATR, XPS, and fluorescence microscopy.