“…Polydiacetylene (PDA) is photopolymerized by ultraviolet (UV) or γ-ray irradiation without chemical initiators or catalysts and possesses unique colorimetric (blue-to-red) and fluorogenic (nonfluorescent-to-fluorescent) properties. − On the basis of these unique properties, PDA has been utilized to fabricate patterned images on solid substrates, which might be highly useful for colorimetric sensors, − arrayed sensor systems, − and molecular cryptography for the detection of counterfeit currency. , For the generation of well-defined PDA patterns, a variety of techniques, including photolithographic methods, ,,− micromolding in capillaries, macro- or microarray spotting, , microcontact printing, patterning with a scanning tunneling microscopy (STM) tip, hydrophobic film-based prepatterning, and electrodynamic jet printing, have been exploited employing an aqueous vesicle, self-assembled layers, and a solution of monomers dissolved in an organic solvent.…”