Banca de QUALIFICAÇÃO: FRANCISCO DHIÊGO SILVEIRA FIGUEIRÊDO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE: FRANCISCO DHIÊGO SILVEIRA FIGUEIRÊDO
DATA: 26/09/2013
HORA: 14:30
LOCAL: Departamento de Química
TÍTULO:

Developing of Prussian blue 2D plattaforms from layer-by-layer method, chitosan and carbon nanotubes

PALAVRAS-CHAVES:

Thin film, Prussian blue, carbon nanotube, biosensor

PÁGINAS: 6
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Inorgânica
ESPECIALIDADE: Campos de Coordenação
RESUMO:

In this work, nanostructured 2D platforms built up frum the biopolymer chitosan (Chit), carbon nanotubes single wall (CNT), complex Prussian blue (PB) polymer and sulfonated polystyrene (PSS) using layer-by-layer (LbL) technique. These nanomaterials were used to construct platforms containing three bilayers {Chit-PB/PSS}₃ and {Chit-CNT-PB/PSS}₃ onto glass tin oxide conductor. Chit-PB and Chit-CNT-PB nanocomposites, and {Chit-PB/PSS}₃ and {Chit-CNT-PB/PSS}₃ thin films were characterized by electronic spectroscopy and cyclic voltammetry techinques. From UV-Vis analysis, it was observed that nanocomposites exhibited a band at ~ 700 nm attributed to intervalence charge transfer (IVCT) from Fe²⁺-CN-Fe³⁺ fragment. Interesting, after NTC incorporation, the IVCT band was shifted after indicating strong interaction between CNT and PB species. Cyclic voltammograms of the platforms exhibited two electrochemical processes with E_(1/2) values at 146 mV (I) and 839 mV (vs SCE) assigned to the conversion of species [Fe²⁺, Fe^2+]/[Fe²⁺-Fe³⁺] and [Fe²⁺, Fe³⁺]/[Fe³⁺, Fe³⁺], respectively. Interesting to mention that both PB 2D platform (with or without CNT) showed good reversibility electrochemical criteria for lower scan rate (e.g. 10 and 50 mVs^-1) indicating slow charge transfer. Based on FT-IR analysis, we observe supramolecular interaction between CNT and PB due a) displacement of cyanide stretching (2079 cm^-1), indicating a π-π stacking which occurs between lateral wall carbon nanotube (electro-donor) and the cyanide group (electro-receiver) of PB and b) electrostatic interaction between PB and CNT, which it was confirmed from C=O stretching at 1714 cm^-1 and COO- symmetrical stretching at 1626 cm^-1. It is expected that the PB 2D platforms have applications in biomedical area including myoglobin biosensor construction.

MEMBROS DA BANCA:
Presidente - 1508806 - WELTER CANTANHEDE DA SILVA
Interno - 1357378 - CARLA VERONICA RODARTE DE MOURA
Interno - 1167626 - GRAZIELLA CIARAMELLA MOITA