Droplet attraction: Surfactants responsive to magnetic fields are reported for the first time. This new class of magnetic ionic liquid surfactants (MILSs; see picture) shows remarkable effects on surface and interfacial tension and allows access to magneto‐responsive emulsions and new methods of separation, recovery, catalysis, and potential magnetophoretic applications.

Multi-functional nanoparticles possessing magnetic, up-conversion fluorescence and bio-affinity properties were synthesized and characterized. The particles have a core/shell structure. Iron oxide nanoparticles of 5-15 nm diameter were synthesized as the magnetic core. The core was covered with ytterbium and erbium co-doped sodium yttrium fluoride (NaYF 4 :Yb,Er), an efficient infrared-to-visible up-conversion phosphor. The phosphor shell was prepared by co-precipitation of the rare-earth metal salts with fluoride in the presence of EDTA and the magnetic nanoparticle. After the magnetic/fluorescent hybrid particle was coated with SiO 2 and activated with glutaraldehyde, streptavidin was immobilized on the particle. The magnetic/fluorescent nanoparticles were found by transmission electron microscopy to be well-dispersed spherical particles with an average diameter of 68 nm. Both energy dispersive X-ray microanalysis and X-ray fluorescence spectra revealed the existence of iron in the particle. Measurements performed on a vibrating sample magnetometer obtained a strong magnetic response for the particle and fluorescence measurements demonstrated its up-conversion property. X-Ray diffraction analysis suggests the phosphor shell has the same structure as the pure NaYF 4 :Yb,Er nanoparticles we prepared in a previous study (G.

This paper reports the molecularly imprinted polymer (MIP)-based fluorescence nanosensor which is developed by anchoring the MIP layer on the surface of silica nanospheres embedded CdSe quantum dots (QDs) via a surface molecular imprinting process. The molecularly imprinted silica nanospheres (CdSe@SiO 2 @MIP) were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), IR spectroscopy, and so forth, which demonstrated the formation of uniform core-shell lambda-cyhalothrin(LC)-imprinted silica nanospheres. The synthesized CdSe@SiO 2 @MIP shows higher photostability, and allows a highly selective and sensitive determination of LC via FL intensity decreasing when removal of the original templates. The CdSe@SiO 2 @MIP was applied to detect trace LC in water without the interference of other pyrethroids and ions. Under optimal conditions, the relative FL intensity of CdSe@SiO 2 @MIP decreased linearly with the increasing LC in the concentration in the range of 0.1-1000 μM with a detection limit (3σ) of 3.6 μg 3 L -1 . It is found that LC can quench the luminescence of CdSe@ SiO 2 @MIP in a concentration-dependent manner that is best described by a Stern-Volmer-type equation. The possible mechanism is discussed.Semiconductor quantum dots (QDs) as high luminescence nanocrystals has attracted considerable attention in recent years, owing to their unique optical and electronic properties, 1,2 such as sharp emission band with broad excitation, and strong resistance to photobleaching. Since Chen and Rosenzweig reported the first practical use of CdS QDs as chemical sensors to determine Zn(II) and Cu(II) ions in aqueous media, 3 a number of QD-based sensors have been reported. [4][5][6][7][8][9][10] For instance, Chen and co-workers have synthesized 15-crown-5 functionalized CdSe/ZnS QDs as a sensing unit toward K þ in aqueous solution. 4 We reported that cyclodextrin modified CdSe/ ZnS QDs allowed a highly sensitive determination of environmental pollutant phenols. 6 Recently, Johnson and coworker have developed a single QD-based aptameric sensor that is capable of sensing the presence of cocaine. 7 Owing to the sustained interest of selective chemo-sensor in environmental monitoring, the design of sensing devices based on QDs is a topic of great interest.In general, surface functionalization is a key to fabricate QD-based probes because of surface modification affording not only the excellent stability of the QDs but also the desired surface binding sites. Among the numerous modifications for QDs, the incorporation of QDs in silica has received considerable attention in the past few years. [11][12][13][14][15] Silica is a good option for the inert material,

acrylamide (tNEA), was synthesized. Atom transfer radical polymerization of tNEA using a poly(ethylene glycol) (PEG) macroinitiator afforded three acid-labile thermoresponsive block copolymers: PEG-b-PtNEA 27 , PEG-b-PtNEA 56 , and PEG-b-PtNEA 73 . These block copolymers are water-soluble at low temperatures (<13 °C). Thermally induced phase transition behaviors, including the critical aggregation temperatures (CATs), of these polymers were investigated by light scattering and 1 H NMR. The results indicated that the longer the PtNEA chain length, the lower the CAT. Upon heating above the CATs, all the three polymers underwent a phase transition and formed polymeric micelles or micelle-like nanoparticles with PEG as the shell and PtNEA block as the core. Both the sizes and morphologies of the micelles were found to be affected by the heating rate and the salt concentration in the buffers. The micelles, formed through a fast heating procedure in the buffer with a relatively high salt concentration, have a smaller size and a more compacted structure. pH-dependent destabilization of the polymeric micelles prepared from PEG-b-PtNEA 73 was studied by using light scattering and Nile Red fluorescence. The results demonstrated that hydrophobic Nile Red could be loaded in the micelles that were stable at pH 7.4, but destabilized in mildly acidic media. The dissociation of the micelles and the subsequent release of Nile Red were induced by the acid-triggered hydrolysis of the orthoester groups, which was proved by the 1 H NMR spectra.