Showing papers by "Helena I. S. Nogueira published in 2011"
TL;DR: In this article, an iron-III mono-substituted Keggin-type polyoxotungstate of formula α-[PW11FeIII(H2O)O39]4− and a sandwich-type tungstophosphate with the formula B-α-[(PW9O34)2FeIII4(H 2O)2]6− were synthesized.
51 citations
TL;DR: In this article, a surface-enhanced Raman scattering (SERS) spectrum was recorded in silver colloid and the vibrational wavenumbers and corresponding vibrational assignments were examined theoretically using quantum mechanical calculations.
38 citations
TL;DR: In this paper, a series of experiments were carried out on Ag/polymer nanocomposites submitted to temperature variations below and above the polymer glass transition temperature (Tg) in order to conclude about the effect of temperature processing conditions on the composites' SERS activity.
Abstract: Nanocomposites containing Ag nanoparticles (average diameter ∼11 nm) dispersed in poly(tert-butylacrylate) were prepared by in situpolymerizationvia miniemulsions and constitute active and versatile SERS substrates. The use of this synthetic strategy enables the dual use of the final composites as SERS substrates, both as aqueous emulsions and as cast films, shown here by several measurements using thiosalicylic acid as the testing analyte. The main advantage of these types of materials is related to the potential to scale up and the widespread use of handy substrates, using technology already available. This requires homogeneous composite substrates with SERS activity and this was demonstrated here by means of confocal Raman microscopy. Finally, a series of experiments were carried out on Ag/polymer nanocomposites submitted to temperature variations below and above the polymer glass transition temperature (Tg) in order to conclude about the effect of temperature processing conditions on the composites' SERS activity.
31 citations
TL;DR: In this article, a new europium(III) supramolecular adduct constructed from α-Keggin-type [PW12O40]3− anions, benzo-15crown-5 and dibenzo-30crown 10 molecules, was prepared and its crystal structure determined by single-crystal X-ray diffraction.
2 citations