Síntese e Caracterização de Nanocompósitos de Polímero Condutor

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Síntese e Caracterização de Nanocompósitos de Polímero Condutor

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Síntese e caracterização de filmes de polipirrol para aplicação como sensor eletroquímico de ácido ascórbico

O ácido ascórbico (AA) é uma importante vitamina presente em diversos alimentos como frutas, verduras e legumes, e que desempenha importante papel na saúde humana, sendo, portanto, a determinação de sua concentração em alimentos e suplementos muito importante para avaliação da qualidade dos mesmos. Diversos métodos são empregados para determinação de sua concentração, dentre eles destaca-se o eletroquímico por se tratar de um método que possibilita a determinação da concentração in situ, sendo mais simples e rápido do que os demais, além de seu baixo custo. Sensores eletroquímicos baseados em polímeros condutores vêm sendo amplamente estudados e aplicados pois possibilitam a combinação das propriedades do polímero e de seus dopantes para obtenção de um material com melhoras no seu desempenho. Neste trabalho foi proposta a síntese de nanocompósitos de polipirrol (PPI) dopado com índigo carmim (IC) e dodecil sulfato de sódio (DS), juntamente com nanopartículas de prata (NPAg), através do método de eletropolimerização in situ. Através de espectroscopia UV-Vis e microscopia eletrônica de varredura verificou-se que a incorporação de DS na matriz do polímero, contribui para o aumento do grau de dopagem e rugosidade. A presença de NPAg e DS contribuíram para melhorar a performance do sensor eletroquímico na determinação do AA. O eletrólito constituído de solução tampão fosfato com pH 3 foi o mais adequado determinação deste analito. Através da curva de calibração foi encontrada uma faixa linear de 0,2 a 2,0 mmol.L-1 e um limite de detecção (LD) de 8,82 μmol.L-1 e 14,5 μmol.L-1 para os filmes PPI-IC-DS e PPI-IC-DS-NPAg, respectivamente. A análise de interferentes mais comumente encontrados em amostras que contém AA mostrou que os materiais obtidos são sensíveis e seletivos para determinação de AA. Portanto, o método proposto é eficiente para obtenção de um sensor eletroquímico de ácido ascórbico, sendo promissor para aplicação em amostras reais.Ascorbic acid (AA) is an important vitamin present in many foods, such as fruits and vegetables, and plays an important role in human health. Therefore, the determination of its concentration in foods and supplements is very important to evaluate their quality. Several methods are used to determine its concentration, among which the electrochemical stands out because it is a method that allows the determination of concentration in situ, is simpler, faster and less expensive than others similar devices. Electrochemical sensors based on conductive polymers have been widely studied and applied because they allow the combination of polymer and dopants properties to obtain a material with improved performance. In this work, the synthesis of polypyrrole (PPI) doped with indigo carmim (IC) and sodium dodecyl sulfate (DS) with silver nanoparticles (NPAg) nanocomposites was proposed using in situ electropolymerization method. Analysis of UV-Vis spectroscopy and scanning electronic miscroscopy showed an increase of doping degree and roughness. The presence of AgNP, in addition to DS, improved the sensor performance on the determination of AA. The phosphate buffer solution with pH 3 was found as the more appropriated electrolyte to determine this analyte. The PPI-IC-DS and PPI-IC-DS-NPAg responded to AA in a linear range from 0.2 to 2.0 mmol.L-1, presenting a limit of detection (LOD) of 8.82 μmol.L-1 and 14.5 μmol.L-1, respectively. Analysis of interference using usual chemical species in samples with AA showed a sensitive and selective material to AA determination. Therefore, the proposed method is efficient to obtain an electrochemical sensor for ascorbic acid, in addition is promising for application in real samples

Simple one-step method to synthesize polypyrrole-indigo carmine-silver nanocomposite

A nanocomposite of indigo carmine doped polypyrrole/silver nanoparticles was obtained by a one-step electrochemical process. The nanocomposite was characterized by scanning electron microscopy, infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and cyclic voltammetry. The simple one-step process allowed the growth of silver nanoparticles during the polymerization of polypyrrole, resulting in films with electrochromic behavior and improved electroactivity. In addition, polypyrrole chains in the nanocomposite were found to present longer conjugation length than pristine polypyrrole films

Simple one-step method to synthesize polypyrrole-indigo carmine-silver nanocomposite

A nanocomposite of indigo carmine doped polypyrrole/silver nanoparticles was obtained by a one-step electrochemical process. The nanocomposite was characterized by scanning electron microscopy, infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and cyclic voltammetry. The simple one-step process allowed the growth of silver nanoparticles during the polymerization of polypyrrole, resulting in films with electrochromic behavior and improved electroactivity. In addition, polypyrrole chains in the nanocomposite were found to present longer conjugation length than pristine polypyrrole films

Simple one-step method to synthesize polypyrrole-indigo carmine-silver nanocomposite

A nanocomposite of indigo carmine doped polypyrrole/silver nanoparticles was obtained by a one-step electrochemical process. The nanocomposite was characterized by scanning electron microscopy, infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and cyclic voltammetry. The simple one-step process allowed the growth of silver nanoparticles during the polymerization of polypyrrole, resulting in films with electrochromic behavior and improved electroactivity. In addition, polypyrrole chains in the nanocomposite were found to present longer conjugation length than pristine polypyrrole films

Simple one-step method to synthesize polypyrrole-indigo carmine-silver nanocomposite

A nanocomposite of indigo carmine doped polypyrrole/silver nanoparticles was obtained by a one-step electrochemical process. The nanocomposite was characterized by scanning electron microscopy, infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and cyclic voltammetry. The simple one-step process allowed the growth of silver nanoparticles during the polymerization of polypyrrole, resulting in films with electrochromic behavior and improved electroactivity. In addition, polypyrrole chains in the nanocomposite were found to present longer conjugation length than pristine polypyrrole films