Ding Cao

Flexible Self-Supporting Nanofibers Thin Films Showing Reversible Photochromic Fluorescence

Highly sensitive stimuli-responsive fluorescent films play an important role in smart sensors and readable optical devices. However, systems involving light-driven fluorescence changes are still limited compared with photochromic materials that simply change color upon photostimulation. Herein, by incorporation of stilbene-based molecules into a poly(vinyl alcohol) host, we have developed new flexible self-supporting nanofiber films that exhibited fast and obvious photochromic fluorescence (PCF). The reversible transfer between two fluorescent states can be easily recycled. Fluorescence microscopy and atomic force microscopy images supplied in situ evidence of changes in fluorescence and surface morphology, respectively. Density functional theoretical calculations showed that the PCF can be attributed to photoisomerization of the stilbene-based molecules. Therefore, based on the combination of experimental and theoretical studies, this work not only supplies new stilbene-based systems with light-induced fluorescence change, but also gives detailed understanding on the photoisomerization and PCF processes of the nanofibers systems. We anticipate that these PCF films can be applied in erasable memory devices and antiforgery materials, and that our strategy may be extended to other systems to fabricate multistimuli-responsive fluorescent materials.

Fast Removal of Cu (II) from Aqueous Solutions by PET Nanofibrous Membrane Modified with Acryamide

A novel nanofibrous membrane was used for removing Cu (II) from aqueous solutions. The poly (ethylene terephthalate) (PET) membranes were fabricated by electrospinning, and then grafted with acrylamide (AM) on the surface. The morphologies of the nanofiber was characterized by SEM, meanwhile, the chemical composition and element analysis on the membrane surface were measured by FT-IR and XPS, respectively. The Cu (II) adsorption experiment investigated the adsorption performance related to the pH value on. Equilibrium studies show that the adsorption process follows Langmuir model and the maximum adsorption capacity was estimated to be 183.25 [mg/g].