Tough, adhesive, self-healing, fully physical crosslinked κ-CG-K+/pHEAA double-network ionic conductive hydrogels for wearable sensors. (30th November 2021)

• Record Type: Journal Article
• Authors: Xu, Jianxiong; Guo, Ziyu; Chen, Yin; Luo, Yuecong; Xie, Shaowen; Zhang, Yutong; Tan, Haihu; Xu, Lijian; Zheng, Jie
• Is Part Of: Polymer. Volume 236(2021)
• Publication Date: 2021-11-30
• Subjects: Conductive hydrogels -- Double-network hydrogels -- κ-carrageenan -- Adhesiveness -- Strain sensor; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.124321
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: The development of multiple-functional conductive hydrogels with combined merits of high mechanical strength, fast self-healing, strong surface adhesion, and strain sensibility has proved to be a highly demanded, but extremely challenging task for different applications. Herein, we designed, synthesized, and characterized fully physically crosslinked double-network (DN) hydrogels of κ-carrageenan/poly( N -hydroxyethyl acrylamide) (κ-CG-K + /pHEAA DN gels) using a facile heating-cooling-photopolymerization process. The resultant κ-CG-K + /pHEAA gels exhibited highly mechanical (tensile strength of 2.02 MPa, tensile strain of 1550%, and elastic modulus of 0.91 MPa) and self-healing properties owing to the interpenetrating DN structures and reversible hybrid ionic-hydrogen bond cross-linking networks. In parallel to high mechanical properties in bulk, κ-CG-K + /pHEAA gels also demonstrated their high surface adhesion of ∼773 J/m 2 on different untreated hard substrates (i.e., titanium, aluminum, ceramic, and glass), which stemmed from the rich-functional groups (hydroxyl and amide) in pHEAA polymer chains. Moreover, the DN gels also presented conductivity, strain sensitivity with gauge factor ( GF ) = 2.48, and sensing stability due to the presence of K + and stretching-dependent resistance variations. Such a unique combination of high mechanical, adhesive, and conductive properties in κ-CG-K + /pHEAA gels allows us to further fabricate them into gel-based strain sensors with high and rapid sensitivity for detecting subtle strain-induced human motions. The design concept and hydrogel system from this work provide a new angle for broad human-machine interface applications. Graphical abstract: Fully physically crosslinked κ-CG-K + /pHEAA DN hydrogels with a combination of superior mechanical, self-healing, conductive, and adhesive properties were successfully prepared and fabricated into wearable strain sensors for human motion monitoring. Image 1 Highlights: ● Fully physically crosslinked κ-CG-K + /pHEAA DN hydrogels were successfully prepared by using a facile process. ● The DN hydrogels achieved combined merits of superior mechanical, self-healing, conductive, and adhesive properties. ● The DN hydrogels can be fabricated into strain sensors with stable and high sensitivity for human motions monitoring.