Abstract

The synthetic conjugated poly(1, 4-arylene-2, 5-thienylene) containing benzo[c][2,1,3]thiadiazolemonomeric units (Bz-PAT) is proposed as active layer for the selective detection of mercuric ions. TheBz-PAT polymer chemical structure induces the formation of a disordered film with numerous vacanciesand the size of these defects could be exploited for a reversible trapping of mercuric ions. For thesereasons the Langmuir-Schaefer (LS) deposition method has been employed for transferring Bz-PATlayers with the desired accurate bi-dimensional organization control of the layer and with a high controlof the deposition parameters. In this contribution, the frequency variation of a quartz crystal microbalancewith 10, 20, 30 and 40 LS runs of Bz-PAT has been investigated in response to the injection of aqueoussolutions of HgCl2, Pb(NO3)2, NiCl2, CdCl2 and ZnSO4 at different concentrations (0.5 mM, 1 mM, 5mM). An almost linear dependence on the number of the LS layers and hence on the film thickness,measured by means of ellipsometric spectroscopy, has been found in terms of sensor response toconcentration of Hg2+ ions fluxed. By means of UV-Vis spectroscopy, the variations in the ?-?*absorption band of the polymer, attributed to the thiophene segment, induced by HgCl2 injection has beenanalyzed and explained as a consequence of the electron transfer from the mercuric ion to the polymersolid film. These results, together with the linear relation found between the number of deposited layersand LS film thickness, suggest that the sensing mechanism can be explained both by an electroninteraction active layer and analyte and a diffusion mechanism of Hg2+ into the solid film that reaches anasymptotic value at 30 runs (about 80 nm), then a higher number of layers does not influence the sensorsensibility.

Autore Pugliese

• Hassan Omar Omar

Tutti gli autori

• Giancane G.; Bettini S.; Pagano R.; Operamolla A.; Hassan Omar O; Babudri F.; Farinola G.M.; Valli L.

Titolo volume/Rivista

Journal of nanoscience and nanotechnology

Anno di pubblicazione

2014

ISSN

1533-4880

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

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Numero di citazioni Scopus

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Settori ERC

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Codici ASJC

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