Controlled Fabrication of Fluorescent Barcode Nanorods

We report a novel technique for generating polymer fluorescent barcode nanorods by reactive ion etching of polymer multilayer films using nonclose-packed (ncp) colloidal microsphere arrays as masks. The fluorescent polymer multilayer films were spin-coated on a substrate, and ncp microsphere arrays were transferred onto these films. The exposed polymers were then etched away selectively, leaving color-encoded nanorods with well-preserved fluorescent properties. By modifying the spin-coating procedure, the amount of polymer in each layer could be tuned freely, which determined the relative fluorescence intensity of the barcode nanorods. These nanorod arrays can be detached from the substrate to form dispersions of coding materials. Moreover, the shape of the nanorods is controllable according to the different etching speeds of various materials, which also endows the nanorods with shape-encoded characters. This method offers opportunities for the fabrication of novel fluorescent barcodes which can be used for detecting and tracking applications.