Received: 10 December 2020 Accepted: 3 February 2021
The present work reports the construction of polypyrrole (PPy) hydrogels directly with the as-synthesized PPy nanotubes (PPy-NTs) through infiltration of poly vinyl alcohol (PVA) and poly(acrylic acid) (PAA) solutions. This method avoids the time-consuming purification of the in-situ formed conducting hydrogels and provides a facile way to incorporate nanostructured conducting polymers evenly into the hydrogel matrix. PPy-NTs/PVA/PAA hydrogels with dual cross-linking networks were prepared through multiple freeze-thawing cycles followed by coordination with iron (III) ions. The tensile and compression strength of the hydrogels are ca. 54 kPa and 160 kPa, respectively. The PPy-NTs/PVA/PAA hydrogel was mainly electronic conducting dominated, and it showed the highest conductivity of ca. 0.04 S/cm after swollen in 0.2 M HCl (with 2wt% of PPy-NTs). Benefited from the high aspect ratio and high conductivity of PPy nanotubes, it is probable to mediate the PPy content and the integrity of the electronic conducting pathways to develop high-performance hydrogel materials used as strain sensors.