Transparent and Mechanically Robust Single‐Network Hydrogels Enabled by Anionic‐Regulated Supramolecular Cross‐linking for Low‐Temperature Human‐Machine Interfaces

ABSTRACT Hydrogel sensors are considered to be one of the promising electronic systems for human‐machine interfaces, but high transparency at the expense of mechanical performance has offset their advantages, which significantly limits their practical applications. Herein, we present one type of single‐network hydrogel constructed by the copolymerization of acrylamide and 𝛼,ω‐diacryloyl poly(ethyleneglycol) in the presence of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The covalent cross‐linking among polymers reinforces the skeleton stability, while the high solubility of LiTFSI promotes its uniform molecular‐level dispersion throughout the polymer network. The high ionic mobility and reversible dynamic hydrogen bonds between TFSI − and polymer networks unlock homogeneous supramolecular cross‐linking, which effectively reduces light scattering and facilitates hierarchical energy dissipation in hydrogels. The transmittance and toughness are as high as 98.93% and 915.04 ± 180.88 kJ m −3 , respectively, which greatly surpass those of other anionic filler counterparts. The resultant hydrogel sensor could serve as a human‐machine interface for gesture recognition with accuracy exceeding 93% even under low‐temperature environments, which enables non‐contact manipulation of robotic hands for grasping objects. This work holds great promise for developing intelligent human‐machine interfaces to execute hazardous and high‐precision tasks.