Visible-Light Transparent, Ultrastretchable, and Self-Healable Semicrystalline Fluorinated Ionogels for Underwater Strain Sensing
Jingxiao Chen, Yufeng Wang, Le Li, Yue‐E Miao, Xu Zhao, Xiu‐Ping Yan, Chao Zhang, Wei Feng, Tianxi Liu
Abstract
The development of ultrastretchable ionogels with a combination of high transparency and unique waterproofness is central to the development of emerging skin-inspired sensors. In this study, an ultrastretchable semicrystalline fluorinated ionogel (SFIG) with visible-light transparency and underwater stability is prepared through one-pot copolymerization of acrylic acid and fluorinated acrylate monomers in a mixed solution of poly(ethylene oxide) (PEO) and fluorinated ionic liquids. Benefiting from the formation of the PEO-chain semicrystalline microstructures and the abundant noncovalent interactions (reversible hydrogen bonds and ion–dipole interactions) in an ionogel, SFIG is rendered with room-temperature stable cross-linking structures, providing high mechanical elasticity as well as high chain segment dynamics for self-healing and efficient energy absorption during the deformation. The resultant SFIG exhibits excellent stretchability (>2500%), improved mechanical toughness (7.4 MJ m –3 ), and room-temperature self-healability. Due to the high compatibility and abundance of hydrophobic fluorinated moieties in the ionogel, the SFIG demonstrates high visible-light transparency (>97%) and excellent waterproofness. Due to these unique advantages, the as-prepared SFIG is capable of working as an ultrastretchable ionic conductor in capacitive-type strain sensors, demonstrating excellent underwater strain-sensing performances with high sensitivity, large detecting range, and exceptional durability. This work might provide a straightforward and efficient method for obtaining waterproof ionogel elastomers for application in next-generation underwater sensors and communications.