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Flexible elastomer material with high stretchability and self-healing performance is the preferred substrates for preparing multi-function flexible sensors and bionic electronic skin. However, it is still a great challenge to...

Flexible WPU elastic films with superior self-healing based on synergic effects between host–guest interactions and hydrogen bonds.

In the past two decades, ionic conductive hydrogel has attracted tremendous research interests for their intrinsic characteristics in the field of flexible sensor. However, synchronous achievement of high mechanical strength, satisfied ionic conductivity, and broad adhesion to various substrates is still a challenge. Herein, a novel zwitterionic composite hydrogel that displayed excited strechability (up to 900%), satisfied strength (about 30 kPa), high ionic conductivity (1.2 mS cm−1), and adhesion to polar and nonpolar materials is fabricated though the combination of waterborne polyurethanes (PU) and poly(sulfobetaine zwitterion‐co‐acrylamide) (SAm). Especially, this facile strategy demonstrates that PU has a synergistic effect on enhancing mechanical strength and ionic conductivity for ionic conductive hydrogel. Moreover, the hydrogel‐based strain/stress sensor shows high sensitivity, wide sensing range, great stability, and accuracy for human body movements detecting and voice recognition. This novel ionic conductive hydrogel has promoted the development of wearable devices.

In this study, nitrogen‐doped carbon dots (N‐C‐dots) are synthesized via a green and gentle electrochemical‐hydrothermal method. The N‐C‐dots are grafted into the backbone of waterborne polyurethane (WBPU) synthesized from hexamethylene diisocyanate and polycarbonate diol (PCDL). Due to the introduction of N‐C‐dots, the WBPU is functionalized including being able to self heal and specifically identified Fe3+. The self‐healing performance of the WBPU‐N‐C‐dots film is principally attributed to the hydrogen bonding effect of the WBPU and the N‐C‐dots. On the other hand, based on the quenching of fluorescent characteristics of the WBPU‐N‐C‐dots film, it is successfully used in the detection of Fe3+, showing a wide detection range, good selectivity, and high sensitivity. What's more, the tensile strength of the sample is enhanced from 3.50 to 7.12 MPa when the N‐C‐dots content is increased in the WBPU and the thermal stability is improved as a result of the formation of the more thermally‐stable network structures. Interestingly, compared to the traditional solution detection in WBPU‐N‐C‐dots emulsion with the limit of detection of 2.23 × 10−6 m, the detection has the lower limit of detection of 2.19 × 10−6 m in the WBPU‐N‐C‐dots film. These results show that the WBPU‐N‐C‐dots film exhibits great application as an intelligent response‐type material.

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Cationic water-based polyurethane(CWPU) was synthesized to explore aloe-emodin modifies to obtain CWPU materials with better comprehensive performance. It provides a simple way to synthesize antibacterial waterborne polyurethane, which is to introduce the end-blocking group of herbal extracts into the structure. It contains synergistic antibacterial effect of herbal antibacterial and quaternary ammonium ion on Escherichia coli . It makes the material resist the erosion of bacterial, and increase the service life of materials. When the pH value of the environment changes, the UV absorbance of the aloe-emodin modified cationic water-based polyurethane(AE-CWPU) also changes. Therefore, within a certain detection range, AE-CWPU has great applications in the field of smart response materials. The modified thermodynamic properties have been improved, and the mechanical properties basically maintained the maximum stress, and the elongation at break was reduced.