Tianmeng Liu,Shuqiang Xiong,Qinchao Sun,Junrong Yu,Yan Wang,Zuming Hu
Aerogel fibers are a new kind of fibrous materials with high porosity and low thermal conductivity, which hold great promise in applications of thermal insulation and personal protection. However, the great differences in mechanisms of gel transformation and fiber spinning, the contradiction between spinnability of spinning solution and crosslinking structure of the gel network, and the difficulty in balancing the key properties of fiber have significantly limited the practical applications of aerogel fibers. Herein, we report a novel “redox-responsive sol-gel transition spinning” method for the continuous spinning of polybenzimidazole/cobalt ion (Co) aerogel fibers, which utilizes the coordination property changes of imidazole ligands and Co with different redox states. The weak coordination interaction between imidazole and Co2+ endows the polybenzimidazole/Co2+ solution with good fluidity and spinnability, while the rapid and uniform oxidation of imidazole/Co2+ to strong imidazole/Co3+ complex in the spinning process allows the construction of a robust crosslinked network. Aerogel fibers obtained with optimal synthetic parameters demonstrate the homogeneous microporous structure in both internal and surface, high mechanical strength, low thermal conductivity, excellent thermal stability, and flame resistance. Furthermore, stretching treatment of organogel fibers prior to drying significantly improves the mechanical properties of aerogel fibers with strength as high as 240.6 MPa. These properties make the aerogel fibers promising for protection applications under extreme environments. The non-covalent crosslinking also permits the recycling of aerogel fibers by dissociation and reconstruction of the coordination bonds. This work is expected to provide a facile approach for continuous spinning of high-performance and recyclable aerogel fibers.
Shaoji Wu,Caihong Gong,Zichao Wang,Sijia Xu,Wen Feng,Zhiming Qiu,Yurong Yan
Hydrogel fibers have attracted substantial interest for application in flexible electronics due to their ionic conductivity, high specific surface area, and ease of constructing multidimensional structures. However, universal continuous spinning methods for hydrogel fibers are yet lacking. Based on the hydrophobic mold induced regional heterogeneous polymerization, a universal self-lubricating spinning (SLS) strategy for the continuous fabrication of hydrogel fibers from monomers is developed. The universality of the SLS strategy is demonstrated by the successful spinning of 10 vinyl monomer-based hydrogel fibers. Benefiting from the universality of the SLS strategy, the SLS strategy can be combined with pre-gel design and post-treatment toughening to prepare highly entangled polyacrylamide (PAM) and ionic crosslinked poly(acrylamide- co -acrylic acid)/Fe 3+ (W-PAMAA/Fe 3+ ) hydrogel fibers, respectively. In particular, the W-PAMAA/Fe 3+ hydrogel fiber exhibited excellent mechanical properties (tensile stress > 4 MPa, tensile strain > 400%) even after 120 days of swelling in the pH of 3–9. Furthermore, owing to the excellent multi-faceted performance and one-dimensionality of W-PAMAA/Fe 3+ hydrogel fibers, flexible sensors with different dimensions and functions can be constructed bottom-up, including the one-dimensional (1D) strain sensor, two-dimensional (2D) direction sensor, three-dimensional (3D) pressure sensor, and underwater communication sensor to present the great potential of hydrogel fibers in flexible electronics.
危险品化学品经营许可证（带存储）