Cat-Tail-Like Mesostructured Silica Fibers Decorated with Gold Nanowires: Synthesis, Characterization, and Application as Stretchable Sensors.

Gold-nanowires (AuNWs)-coated mesostructured silica fibers that have the appearance of a cat's tail have been successfully designed and synthesized. The silica fibers had a Brunauer-Emmett-Teller (BET) surface area of 347 m2  g-1 and Barret-Joyner-Halenda (BJH) pore size of 3.8 nm. Negatively charged gold seeds could be anchored onto the surface of mesoporous silica fibers through electrostatic attraction. Further treatment with growth solution (including HAuCl4 , 4-mercaptobenzoic acid, and ascorbic acid) enabled successful growth of vertically aligned AuNWs with controllable lengths on the silica fiber surfaces. These coaxial mesostructured silica microfibers conjugated with AuNWs exhibit excellent stability and real-time response with high durability (≥2500 cycles) as a sensitive flexible microelectronic material. The fabricated device is able to detect the human pulse (measured at the wrist), as well as small-amplitude finger motion.