Cellulose Acetate Fibers with Fluorescing Nanoparticles for Anti-counterfeiting and pH-sensing Applications

Abstract

Fluorescent silica nanoparticles, Cornell dots (Cdots), were incorporated into electrospun celluloseacetate (CA) fibers. Two types of C dots were usedin this study. The first type was comprised of afluorescent dye-containing silica core surrounded bya silica shell. These nanoparticles fluoresce at 572nm when exposed to 541 nm light. Increasing C dotloading in the spinning dope above 10% w/w did notresult in an increase in C dot content within the finalfibers. Scanning electron microscopy indicated thatthe nanoparticle incorporation had very little effecton the fiber morphology. The mechanicalproperties of the electrospun fabrics were notnegatively affected by C dot addition, even thoughfinal loading constituted nearly one-third of theweight of the fibers. A second type of C dots, withboth a fluorescent core and a pH-sensitive shell, werealso incorporated in CA fibers. These C dotsfluoresce at both 572 nm as described above, and at518 nm, when exposed to 488 nm light.Fluorescence intensity at 541 nm increased withincreasing pH. For both nanoparticle-incorporatedfabrics, the resulting fibers are white under ambientlighting, and fluoresce at their given wavelengths oflight.