Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Conductive hydrogels, particularly soft systems, face the key challenge of integrating high mechanical robustness, excellent conductivity, and self-healing. This study introduces β-cyclodextrin-functionalized carbon nanotubes to create a hydrogel achieving a low modulus while also delivering enhanced toughness, remarkable self-healing efficiency, and superior conductivity for flexible strain and stress sensing applications.

ABSTRACT
Conductive hydrogels hold great promise for applications in flexible sensors. However, for such soft hydrogel systems, achieving a synergistic integration of high mechanical robustness, excellent conductivity, and outstanding self-healing capability remains a significant challenge. To address this issue, this study introduces β-cyclodextrin-functionalized multi-walled carbon nanotubes (β-CD@MWCNTs) combined with a dynamic redox initiation system undergoing rapid polymerization to prepare hydroxyethyl cellulose/polyacrylic acid/β-CD@MWCNTs (HEC/PAA/β-CD@MWCNTs) semi-interpenetrating network hydrogels. The incorporated β-CD@MWCNTs serve as additional physical crosslinking points within the system, which not only markedly enhance the mechanical properties of the hydrogel—including fracture strain (1407.28%), toughness (734.71 kJ m−3)—while retaining the low modulus (13.08 kPa) characteristic of typical hydrogels, but also confer a remarkable self-healing capability (with up to 88.65% healing efficiency for elongation at break). Furthermore, β-CD@MWCNTs can form a stable ion-electron synergistic conductive pathway with Fe3+, endowing the hydrogel with excellent electrical conductivity (37.21 mS cm−1) and high strain sensitivity (gauge factor [GF] = 3.77). This study introduces functionalized carbon nanotubes, providing a novel strategy for developing high-performance conductive hydrogels that combine low modulus with high stretchability, excellent conductivity, and self-healing capability, underscoring their broad application potential in flexible sensing including human motion monitoring, information encryption, and handwriting anti-counterfeiting.