10.1021/acsami.9b21659.s001 Zhihui Qin Zhihui Qin Xia Sun Xia Sun Qingyu Yu Qingyu Yu Haitao Zhang Haitao Zhang Xiaojun Wu Xiaojun Wu Mengmeng Yao Mengmeng Yao Wenwen Liu Wenwen Liu Fanglian Yao Fanglian Yao Junjie Li Junjie Li Carbon Nanotubes/Hydrophobically Associated Hydrogels as Ultrastretchable, Highly Sensitive, Stable Strain, and Pressure Sensors American Chemical Society 2020 conductive hydrogel fatigue resistance hydrogel network anti-fatigue conductive nanocomposite hydrogel pressure sensors strain sensitivity hydrogel-based sensors carbon nanotubes MJ anti-fatigue property Pressure Sensors Conductive hydrogels amphiphilic sodium dodecyl sulfate gauge factor large-pressure region skin-like sensors uniform dispersion wearable strain CNT surface hydrogel matrix Stable Strain strain ranges 2020-01-17 16:40:07 Journal contribution https://acs.figshare.com/articles/journal_contribution/Carbon_Nanotubes_Hydrophobically_Associated_Hydrogels_as_Ultrastretchable_Highly_Sensitive_Stable_Strain_and_Pressure_Sensors/11638239 Conductive hydrogels have become one of the most promising materials for skin-like sensors because of their excellent biocompatibility and mechanical flexibility. However, the limited stretchability, low toughness, and fatigue resistance lead to a narrow sensing region and insufficient durability of the hydrogel-based sensors. In this work, an extremely stretchable, highly tough, and anti-fatigue conductive nanocomposite hydrogel is prepared by integrating hydrophobic carbon nanotubes (CNTs) into hydrophobically associated polyacrylamide (HAPAAm) hydrogel. In this conductive hydrogel, amphiphilic sodium dodecyl sulfate was used to ensure uniform dispersion of CNTs in the hydrogel network, and hydrophobic interactions between the hydrogel matrix and the CNT surface formed, greatly improving the mechanical properties of the hydrogel. The obtained CNTs/HAPAAm hydrogel showed excellent stretchability (ca. 3000%), toughness (3.42 MJ m<sup>–3</sup>), and great anti-fatigue property. Moreover, it exhibits both high tensile strain sensitivity in the wide strain ranges (gauge factor = 4.32, up to 1000%) and high linear sensitivity (0.127 kPa<sup>–1</sup>) in a large-pressure region within 0–50 kPa. The CNTs/HAPAAm hydrogel-based sensors can sensitively and stably detect full-range human activities (e.g., elbow rotation, finger bending, swallowing motion, and pronouncing) and handwriting, demonstrating the CNTs/HAPAAm hydrogel’s potential as the wearable strain and pressure sensors for flexible devices.