Fabricating ultra-robust hydrogels with adhesive properties by restraining crack propagation with bamboo cellulose-based carbon nanomaterials
Xin Duan, Huanxin Huo, Hongshan Li, Yihong Gao, Haoran Shi, Feng Kuang, Yumeng Chen, Jianyong Wan, Jingjie Shen, Guanben Du, Long Yang
Abstract
The bamboo fiber functionalized with phthalic anhydride underwent carbonization, yielding bamboo cellulose-derived carbon nanomaterials (C-BCN). These C-BCN were subsequently integrated into an acrylamide precursor solution to synthesize an ultra-robust, fatigue-resistant conductive hydrogel (PAM-C-BCN). During in situ polymerization, the abundant active sites on the C-BCN surface facilitated covalent cross-linking with the polyacrylamide (PAM) matrix. This interfacial interaction promoted strong adhesion between the PAM chains and the carbon nanostructures, forming a densely interpenetrated network through macromolecular entanglement. The synergistic coupling of the rigid C-BCN framework with the flexible polymer chains conferred exceptional mechanical resilience and energy dissipation capabilities to the composite hydrogel. Compared to the PAM hydrogel, the PAM-C-BCN hydrogel exhibited an improvement in mechanical properties, with a fracture strength of 363 kPa (a 2.5% increase), an elongation of approximately 2 254% (a 2.0% increase), a fracture energy of 30 kJ/m 2 (a 3.1% increase), and a toughness of 3.04 MJ/m 3 (a 4.1% increase). Moreover, PAM-C-BCN hydrogel demonstrated high adhesion (up to 7.5 kPa on pigskin) and conductivity (0.21 S/m). This strategy required neither complex design nor processing, offering a simple and efficient approach with great potential for hydrogel applications requiring high mechanical performance. At the crack tip of PAM-C-BCN hydrogel, C-BCN exhibited superior crack propagation resistance compared to SiO 2 nanoparticles. Importantly, this strategy offered valuable insights for developing tough and stretchable hydrogels.