Traditional hydrogels are easily frozen or evaporated under colder or hotter temperatures, resulting in their performance degradation. In this paper, polyacrylic acid, sodium alginate, carbon nanotubes, water, and glycerol are used to synthesize self-healing, wearable, freezing resistance, and dry resistance conductive hydrogels with interpenetrating crosslinking network structure. The dynamic cross-linking network structure of the hydrogel can rapidly recover and restructure after damage. In addition, the conductive hydrogels exhibit excellent adhesion to various materials (including PTFE, iron, glass, plastic, and skin). Conductive hydrogel has excellent strain-electric sensing properties, and has high sensitivity, significant stability and repeatability. The conductive hydrogel can be used to test the movement of fingers and knee joints by strain sensing, and has excellent, sensitive, and stable resistance response. Therefore, the conductive hydrogel can be used as a wearable strain sensor for real-time detection of human joint movement. The hydrogel has better environmental adaptability and broad application prospects.
The structural diversity of polyphenols and the inherent limitations of current extraction techniques pose a challenge to extract polyphenols using a simple and green method. Hence, in this study, a method was developed to simultaneously fractionate multiple classes of polyphenols by only varying ethanol-water solutions. Honeybush tea, which is rich in polyphenols, was selected as a model for this study. Solvent extraction followed by solid-phase extraction (SPE) was developed to obtain a polyphenol-rich fraction from six honeybush samples. Based on a gradient elution programme (10%, 30%, 50%, 70% and 90% (v/v) ethanol-water solution) of SPE, the Strata X cartridge showed a better recovery of most targeted polyphenols under 0.9 mL of the drying volume and 1 mL min−1 of the dispensing speed. The elution programme for fractionating most polyphenols was as follows: single elution with 50% ethanol, followed by twice elution with 70% ethanol. The antioxidant capacity was used to analyse the differences among the polyphenol-rich fractions from six honeybush samples. Principal component analysis (PCA) revealed that unfermented C. genistoides (GG) has the greatest antioxidant capacity among the honeybush species studied. Additionally, mangiferin, isomangiferin and vicenin-2 were the main contributors to the antioxidant capacity in six honeybush fractions according to the correlation study. 相似文献