Stretchable, healable, biocompatible, and conductive hydrogels are one of the promising candidates for both wearable electronics and environmental remediation applications. To date, the design of hydrogels that integrate ultrafast self-healing with high efficiency (seconds), high stretchability, and biocompatibility and reversibility into one system is not an easy task. Herein, we demonstrate a general oxidation approach to accelerate the hydrogelation of hPEI-based double network gels via the generation of fluorescent polymer clusters at room temperature or triggered by the heating–cooling process. The resulting ohPEI hydrogel has the merit of biocompatibility over most reported hPEI hydrogels for strain sensors. It shows a high conductivity (1.3 S/m), an ultrafast self-healing ability (<3 s, 98% healing efficiency within 60 s), a high stretchability (∼1850 and ∼7000% in deformation), and reversible adhesivity on various material surfaces. The excellent performance of the hydrogel is ascribed to the cooperative and hierarchical interactions of four types of dynamic combinations, including the reversible borate bond, hydrogen bonding, electrostatic interaction, and polymer cluster interactions. The reversible fabrication process by the one-spot method (just by simple mixing of the components) and superior properties of the hydrogel make it an ideal candidate for a wearable strain sensor to monitor human motions and physiological activities. Moreover, it is also a good hydrogel absorbent for phase separation absorption of volatile organic compounds with a high capacity (for acetone: 4.75 g g–1), reusability, and an easy handling process.

A huge amount of data inundated in our daily life; there is an ever-increasing need to develop a new strategy of information encryption–decryption–erasing. Herein, a polymeric DCTpy/PAM hydrogel has been fabricated to store information via controllable Eu3+/Zn2+ ionoprinting for hierarchical and multidimensional information decryption. Eu3+ and Zn2+ have a competition and dynamic interaction toward DCTpy under NH3 stimuli in the polymeric DCTpy/PAM hydrogel network. The Eu(III)/Zn(II)@DCTpy/PAM hydrogel exhibits light red fluorescence of Eu3+ due to the antenna effect. Upon the addition of NH3, dissociation of the Eu3+–DCTpy complex takes place, and the Zn(II)/DCTpy/NH3 complex is formed with both ICT (intramolecular charge-transfer) and PET (photo-induced electron-transfer) process characteristics that exhibits yellow emission color. Subsequently, HCl can quench the fluorescence of the resulting hydrogel. By integrating transparency, adhesiveness, and programmable stimuli responsiveness of the hydrogel blocks in to one system, complex, multistage, and time-controlled information storage–encryption–decryption–erasing in sequence with multidimensions is illustrated via the molecule diffusion method. This work provides a novel and representative strategy in fabricating information encryption–decryption-erasing materials with high capacity and complexity by a simple terpyridine-based hydrogel.