title: Effect of low and high methoxyl citrus pectin on the properties of polypyrrole based electroactive hydrogels.
abstract: Electroactive hydrogels were prepared using commercial citric pectin, either raw (PC) or purified through dialysis (dPC), and chemically synthesized polypyrrole (PPy).1H NMR analyses showed that PC is a low methoxyl pectin (degree of methoxylation, DM=46%) and dPC is a high methoxyl pectin (DM=77%). The pyrrole polymerization was monitored through UV-vis spectroscopy and both samples were observed to be good stabilizers for PPy in aqueous medium. The dispersions were used to prepare the hydrogels h-PC-PPy and h-dPC-PPy. The hydrogel h-dPC-PPy has a higher swelling index (SI≈25%) at pH 1.2 than the hydrogel h-PC-PPy (SI≈7%). Contrastingly, at pH 6.8 both hydrogels lost their mechanical integrity. Raman spectroscopy revealed that PPy is more oxidized in h-PC-PPy. Nevertheless, both hydrogels are electroactive and therefore can be considered for applications in which the control of the degree of swelling is desired.
authors.affiliation: Grupo de Pesquisa em Macromoléculas e Interfaces, Departamento de Química, Universidade Federal do Paraná - UFPR, CxP 19032, CEP 81531-980, Curitiba, PR, Brazil.
authors.forename: Laís C
authors.initials: LC
authors.lastname: Lopes
authors.affiliation: Grupo de Pesquisa em Macromoléculas e Interfaces, Departamento de Química, Universidade Federal do Paraná - UFPR, CxP 19032, CEP 81531-980, Curitiba, PR, Brazil.
authors.forename: Fernanda F
authors.initials: FF
authors.lastname: Simas-Tosin
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná - UFPR, CxP 19046, CEP 81531-980, Curitiba, PR, Brazil.
authors.forename: Thales R
authors.initials: TR
authors.lastname: Cipriani
authors.affiliation: Grupo de Pesquisa em Macromoléculas e Interfaces, Departamento de Química, Universidade Federal do Paraná - UFPR, CxP 19032, CEP 81531-980, Curitiba, PR, Brazil; Universidade Tecnológica Federal do Paraná, Av. Monteiro Lobato s/n Km 04, CEP 84016-210 Ponta Grossa, PR, Brazil.
authors.forename: Luís F
authors.initials: LF
authors.lastname: Marchesi
authors.affiliation: Grupo de Pesquisa em Macromoléculas e Interfaces, Departamento de Química, Universidade Federal do Paraná - UFPR, CxP 19032, CEP 81531-980, Curitiba, PR, Brazil.
authors.forename: Marcio
authors.initials: M
authors.lastname: Vidotti
authors.affiliation: Grupo de Pesquisa em Macromoléculas e Interfaces, Departamento de Química, Universidade Federal do Paraná - UFPR, CxP 19032, CEP 81531-980, Curitiba, PR, Brazil. Electronic address: izabel.riegel@ufpr.br.
authors.forename: Izabel C
authors.initials: IC
authors.lastname: Riegel-Vidotti
keywords: Electroactive hydrogel; Pectin; Polypyrrole; pH-sensitive