Remote multi-color excitation using femtosecond propagating surface plasmon polaritons in gold films.

We demonstrate dual-color nonlinear excitation of quantum dots positioned onto a gold film at distances up to 40 µm away from a micrometer sized focused laser spot. We attribute the observed remote nonlinear signal to the excitation of two independent surface plasmon polariton (SPP) modes excited at the laser spot in the gold film, which subsequently propagate in a collinear fashion to a distant site and provide the surface field required for nonlinear excitation of the target. This scheme decouples the illuminating photon flux from surface plasmon mediated nonlinear excitation of the target, which provides more control of unwanted heating effects at the target site and represents an attractive approach for surface-mediated femtosecond nonlinear examinations of molecules.

Novel Molecular Organic Framework Composite Molecularly Imprinted Nanofibrous Membranes with a Bioinspired Viscid Bead Structure for Selective Recognition and Separation of Atrazine.

In this work, novel atrazine (ATZ) molecularly imprinted nanofibrous membranes (A-MNMs) with a molecular organic framework (MOF)-based viscid bead structure were developed based on a natural spider-web-inspired strategy for selective separation of ATZ. Poly(vinylidene fluoride)/poly(vinyl alcohol) (PVDF/PVA) blended nanofibrous membranes as the basal membrane were synthesized by electrospinning technology combined with a chemical cross-linking procedure. The most critical design is that MOF nanocrystals as the matrix of the viscid bead structure were assembled on the PVDF/PVA blended nanofibrous membrane surface and the specific recognition sites were efficiently constructed on the surface and pores of the MOF-based viscid bead structure by a surface imprinting strategy. Significantly, the as-synthesized MOF-based viscid bead structure has an enhanced specific surface area, which helps to form abundant specific recognition sites in A-MNMs. Therefore, the A-MNMs with a spider-web-like structure presented an enhanced rebinding capacity (37.62 mg g-1) and permselectivity (permselectivity factors ß were 4.21 and 4.31) toward ATZ. Moreover, the A-MNMs display strong practicability in separation of ATZ from simulated environmental water samples. The presented work has shown tremendous potential for preparing natural spider-web-like molecularly imprinted membranes (MIMs) for selective separation of environment pollutants.