A highly elastic and sensitive sensor based on GSP/HPAM composited hydrogel

Development of conductive hydrogels to mimic the structures and properties of human skin has attracted enormous scientific interests. However, applications of such materials are often restricted by their poor mechanics and moderate sensitivities. Herein, a highly-stretchable, self-healing, and conductive hydrogel, comprised of grape seed extracted polymer and hydrophobically associated polyacrylamide (GSP-HPAM), was fabricated by simple mixing and in-situ polymerization. Compared with the single HPAM gels, the rigid GSP polymer could form sufficient hydrogen bonds and ionic interactions, which endowed the gel with effective energy dissipation mechanism and greatly improved the uniformity of network. As a result, the GSP-HPAM gel exhibited enhanced mechanics, that is, the tensile strength, strain, and compression stress of GSP-HPAM hydrogel were 0.7 MPa, 3000% and 28.3 MPa, respectively. Furthermore, the gel demonstrated linear strain-dependant conductivity between 0% and 1000% with gauge factor around 3.43, superior to most hydrogel-based strain sensors. In addition, the gel was able to monitor human body motion, such as, finger bending and pulse rate. This multiple functional gel might find potential applications in artificial skin, soft robotics, and wearable devices.