Hua Yuan,Jiaqi Zhang,Caixia Li,Jie Xin Wang,Yuan Le
Currently, flexible capacitive pressure sensors (CPSs) with excellent performances are highly desired in the field of wearable electronics. Raw material selection, rational structure design and simple preparation method are both worth considering. In this work, a simple strategy to construct flexible ionic fiber CPSs based on chrome shavings is proposed. Ionic donor, water-soluble ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate [EMIM][OTF] mixed with the fully swollen chrome shavings collagen fibers (CFs) to obtain the ionic fiber via drying. Chrome shavings CFs support rough surfaces and porous structures, ionic liquids provide ionic conductive sensing properties. The prepared ionic fiber displays outstanding sensing performances due to the synergistic effect of flexible fibrous matrix and ionic donor. The optimized ionic fiber CPS exhibits high sensitivities of 5.37 kPa-1 (0-1.2 kPa), 1.7 kPa-1 (1.2-7 kPa), 0.95 kPa-1 (7-15.8 kPa) and achieves the recognition of human activity signals. Meanwhile, the sensor displays outstanding environmental adaptability and the application potential in the field of temperature sensing. This work offers a new approach for preparing high-performance and cost-effective fiber-based CPSs, as well as the resource utilization and high-value utilization of chrome shaving CFs.
Renewable bio-based electromagnetic interference (EMI) shielding materials receive increasing attention undoubtedly. However, there is still a challenge to use raw biomass materials to construct a significant structure through an effortless and environmental route for EMI shielding applications. Herein, for the first time, we demonstrated a hybrid composite of multi-walled carbon nanotube/polypyrrole/chrome-tanned collagen fiber (MWCNT/PPy/CF), which utilized waste chrome shavings as a matrix. X-ray photoelectron spectroscopy reveals that the chromium on the CF has a binding effect on the PPy layer, which endows the tight integration between the CF and PPy layer. After the MWCNT network was loaded on the PPy layer, this ternary structure could provide stable conductive paths and a rich number of polarized interfaces. The MWCNT/PPy/CF composite exhibits superior electrical conductivity (354 ± 52 S/m), higher than PPy/CF (222 ± 38 S/m) and MWCNT/CF (104 ± 11 S/m), owing to the synergy of dual conductive structures. Notably, the shielding effectiveness (SE) value of the MWCNT/PPy/CF composite reaches 30 dB in the X band at a thickness of 0.48 mm. The shielding effectiveness of reflection (SER) (9.1 dB) is similar to that of PPy/CF (8.2 dB), while the shielding effectiveness of absorption (SEA) is significantly improved from 15.3 dB (PPy/CF) to 20.4 dB (MWCNT/PPy/CF) due to the additional coverage of the MWCNT network. This indicates the synergy between the MWCNT network and conductive PPy/CF skeleton. This work provided a method to prepare sustainable and low-cost renewable EMI shielding materials using chrome shavings. Meanwhile, this novel structure combining a conductive skeleton and heterostructure can be considered as a potential application in relevant fields.
危险品化学品经营许可证（带存储）