Inclusion of thiol DAB dendrimer/CdSe quantum dots based in a membrane structure: Surface and bulk membrane modification

The behavior of a fluorescent nanocomposite, obtained by means of a thiol polypropylenimine dendrimer of third generation coated with CdSe quantum dots, and embedded in a hydrophilic cellulosic membrane as support is electrochemically studied in order to evaluate its applicability as a sensor in liquid media. The characterization of the nanocomposite by TEM and EDAX shows uniform nano morphology (size comprised in the range 60–90 nm) and composition, respectively. The analysis of the engineered hybrid cellulose-dendrimer quantum dots material by confocal fluorescence microscopy indicates almost mono-dispersion distribution of the nanocomposite when irradiated under UV light, while its presence on the film surface was determined by X-ray photoelectron spectroscopy. Impedance spectroscopy measurements performed with dry membrane samples show a decrease in the conductivity and dielectric constant of the modified membrane in comparison with the raw support. Electrical changes in the modified film associated to the presence of Cd(II) uptakes from a Cl2Cd solution were also obtained. These results support the possible application of this nanocomposite material as heavy metal sensor in liquid media.

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► Fluorescent nanocomposite based in CdSe quantum dots (QDs) coated by thiol polypropylenimine (DAB).
► Bulk chemical characterization by TEM and EDAX
► Inclusion of the S-DAB-CdSe QDs in a cellulosic support and its characterization by Fluorescence and XPS.
► Electrical characterization by Impedance Spectroscopy of dry and wet samples containing a heavy metal.