Effect of low and high methoxyl citrus pectin on the properties of polypyrrole based electroactive hydrogels. (2nd January 2017)

• Record Type: Journal Article
• Authors: Lopes, Laís C.; Simas-Tosin, Fernanda F.; Cipriani, Thales R.; Marchesi, Luís F.; Vidotti, Marcio; Riegel-Vidotti, Izabel C.
• Is Part Of: Carbohydrate polymers. Volume 155(2016)
• Page Start: 11
• Page End: 18
• Publication Date: 2017-01-02
• Subjects: Electroactive hydrogel -- pH-sensitive -- Pectin -- Polypyrrole; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2016.08.050
• Languages: English
• ISSNs: 0144-8617

Abstract

Graphical abstract: Highlights: ⿢ Low and high methoxyl citrus pectin were obtained through dialysis. ⿢ Polypyrrole was synthetized in the presence of low and high methoxyl citrus pectin. ⿢ The properties of polypyrrole/pectin hydrogels depend on the methoxyl content. ⿢ Polypyrrole/citrus pectin hydrogels are electroactive. Abstract: Electroactive hydrogels were prepared using commercial citric pectin, either raw (PC) or purified through dialysis (dPC), and chemically synthesized polypyrrole (PPy). 1 H 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.