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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Multivariate statistical analysis of chemical and electrochemical oscillators for an accurate frequency selection

Texto completo
Autor(es):
Kitagaki, Bianca T. [1] ; Pinto, Maria R. [1] ; Queiroz, Adriana C. [1, 2] ; Breitkreitz, Marcia C. [1] ; Rossi, Federico [3] ; Nagao, Raphael [1, 2]
Número total de Autores: 6
Afiliação do(s) autor(es):
[1] Univ Estadual Campinas, Inst Chem, BR-13083970 Campinas, SP - Brazil
[2] Univ Estadual Campinas, Ctr Innovat New Energies, BR-13083841 Campinas, SP - Brazil
[3] Univ Siena, Dept Earth Environm & Phys Sci DEEP Sci, Pian Mantellini 44, I-53100 Siena - Italy
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: Physical Chemistry Chemical Physics; v. 21, n. 30, p. 16423-16434, AUG 14 2019.
Citações Web of Science: 0
Resumo

The effect of experimental parameters on the frequency of chemical oscillators has been systematically studied since the first observations of clock reactions. The approach is mainly based on univariate changes in one specific parameter while others are kept constant. The frequency is then monitored and the effect of each parameter is discussed separately. This type of analysis, however, does not take into account the multiple interactions among the controllable parameters and the synergic responses on the oscillation frequency. We have carried out a multivariate statistical analysis of chemical (BZ-ferroin catalyzed reaction) and electrochemical (Cu/Cu2O cathodic deposition) oscillators and identified the contributions of the experimental parameters on frequency variations. The BZ reaction presented a strong dependence on the initial concentration of sodium bromate and temperature, resulting in a frequency increase. The concentration of malonic acid, the organic substrate, affects the system but with lower intensity compared with the combination of sodium bromate and temperature. On the other hand, the Cu/Cu2O electrochemical oscillator was shown to be less sensitive to changes in the temperature. The applied current density and pH were the two parameters which most perturbed the system. Interestingly, the frequency behaved nonmonotonically with a quadratic dependence. The multivariate analysis of both oscillators exhibited significant differences-while the homogenous oscillator displayed a linear dependence with the factors, the heterogeneous one revealed a more complex dependence with quadratic terms. Our results may contribute, for instance, in the synthesis of self-organized materials in which an accurate frequency selection is required and, depending on its value, different physicochemical properties are obtained. (AU)

Processo FAPESP: 17/05592-4 - Resolução espaço-temporal de óxidos metálicos superficiais em osciladores eletroquímicos
Beneficiário:Maria Rodrigues Pinto
Linha de fomento: Bolsas no Brasil - Mestrado
Processo FAPESP: 17/22387-5 - Oscilações e multiestabilidade em reações orgânicas de relevância prebiótica
Beneficiário:Bianca Tieme Kitagaki
Linha de fomento: Bolsas no Brasil - Iniciação Científica
Processo FAPESP: 16/01817-9 - Desenho e controle de padrões eletroquímicos auto-organizados
Beneficiário:Raphael Nagao de Sousa
Linha de fomento: Auxílio à Pesquisa - Apoio a Jovens Pesquisadores
Processo FAPESP: 17/11986-5 - Divisão de Pesquisa 1 - portadores densos de energia
Beneficiário:Ana Flávia Nogueira
Linha de fomento: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia