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Effect of low and high methoxyl citrus pectin on the properties of polypyrrole based electroactive hydrogels

2016; Elsevier BV; Volume: 155; Linguagem: Inglês

10.1016/j.carbpol.2016.08.050

1879-1344

Laís C. Lopes, Fernanda Fogagnoli Simas, Thales R. Cipriani, Luís F. Marchesi, Márcio Vidotti, Izabel C. Riegel‐Vidotti,

Hydrogels: synthesis, properties, applications

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.