Developing a ternary conductive hydrogel of polyacrylamide, polyaniline, and carbon nanotube: A potential chemiresistive gas sensor

Abstract

Over the past few years, conductive hydrogels have received increasing attention for numerous electronic applications because of the concurrent provision of electrical conductivity, flexibility, and conformability. In the present study, a polyaniline-based conductive hydrogel was synthesized. Carbon nanotubes (CNTs) were associated with the hydrogel to impart higher electrical conductivity to the hydrogel, and ternary composites of polyacrylamide (PAM), polyaniline (PANI), and CNT were developed. To fulfill this, at first, CNT surface was decorated with carboxyl functionalities, and the carboxyl decorated CNT was included into the composition in two manners: firstly, CNTs were included during acrylamide polymerization, whereas in the second manner, CNTs were incorporated during aniline polymerization. The composite hydrogels' chemical, swelling, morphological, and electrical properties were evaluated. The experimental results corroborated that in the latter case, abundant intermolecular interactions were developed between the PANI chains and the CNT surface. Moreover, the swelling value was increased by 9% comapred to the former case. In the former case, a porous microstructure and in the latter case a fibrous microstructure was dominated. And more importantly, the electrical conductivity of the hydrogel in the latter case was 104 folds higher than that in the former case. The ternary composition prepared with the latter manner was employed for sensing the ammonia gas, and the analyses unveiled that the hydrogel represents an appropriate response in the range of 10.43%–16.87% to various concentrations of the target gas and has the potential to be a thriving chemiresistive gas sensor.