Flexibility, waterproof and breathability of substrates are the key issues restricting the application of electronic skin. Composite nanofibrous membranes (CNFMs) as substrates of electronic skin are prepared from polyvinylidene fluoride and silver nitrate blended solution by electrospinning technique. The microstructure and performances of the CNFMs are characterized by scanning electron microscopy, x-ray diffraction, capillary pore size analyzer, gravimetric method, water vapor permeability tester, optical contact angle tester, water permeability tester, intelligent electronic strength tester, hand-held electronic thickness meter and seveneasy conductivity meter. The results indicate that with the introduction of silver nitrate, the waterproof and breathability of CNFMs are balanced and optimized. The moisture permeability increases by 22%–69% from 2915.9 g · m−2 · 24 h−1 of pristine nanofibrous membrane (PNFM) to 3801.2–4151.5 g · m−2 · 24 h−1 of CNFMs and the hydraulic pressure decreases from 23.4 kPa to 21.6–16.5 kPa. However, the change of contact angle is irregular, which depends on the presence of like lotus-leaf-papillae morphology on fiber surface. The tensile strength of CNFMs decreases greatly and the elongation increases by 3–8 times from 7.7% of PNFM to 25.1%–63.2% of the CNFMs. The improvement of CNFMs flexibility is attributed to the hierarchical roughness of nanofiber surface, the unlock bonding between fibers and various combination forms of silver particles in CNFMs. Thus it was suitable to be applied as the substrate of electronic skin.

Flexible alumina (Al2O3)/carbon (C) composite nanofibers film has been fabricated via electrospinning, followed by pre-oxidation and carbonization. Polyacrylonitrile (PAN)/Polyvinylpyrrolidone (PVP) and aluminum hydroxyacetate (Al(OH)C4H6O4) acted as carbon precursor and Al2O3 precursor, respectively. The obtained Al2O3/C nanofibers films were systematically characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), energy dispersive spectrometer (EDS), X-ray diffractometer (XRD) and flexural tests. The results indicated that Al2O3/C composite nanofibers with rough surface consisted of graphitic phase and γ-Al2O3 phase. The Al2O3 covering on the surface of nanofibers improved the flexibility of carbon nanofibers (CNFs) film. Moreover, with the amount of Al2O3 increasing, both flexural rigidity and flexural modulus of Al2O3/C nanofibers film decreased drastically. In the other words, the flexibility of CNFs film improved greatly. The Al2O3/C nanofibers film with the mass ratio of Al(OH)C4H6O4: PAN being 4:1 exhibited flexural modulus that was about 11 times lower than that of CNFs film without Al2O3, suggesting that the highly flexible Al2O3/C nanofibers film was obtained.

Charge transfer reactions between C60, C70 and pyridine.

Fiber air dispersion system (FADS) is a new flexible ventilation terminal in ventilated areas. It can be used in both air transmission and air diffusion. The cloth duct made of flame retardant polyester is critical. The conditioned air can be dispersed to environment by not only micro pores in the fabric but also slot and orifice on the fabric. The micro-pores in the fabric exist in the yarns and fibers. The laser can be used to cut the slot and orifice on the fabric. They can be designed based on the application. In this paper, air dispersion models and basic characteristics of fiber air dispersion system were introduced. Based on computational fluid mechanics theory, the flame retardant cloth ducts (FRCD) is regard as an isotropic porous media. The air dispersion physical model for micro porous that sends the air to the environment was established. And the Carman-kozeny equation was used in this model, which was described the airflow field in the FRCD. Finally the airflow field in the FRCD was numerically simulated with the FLUENT software based on the finite element method. The air flow resistance of the fabrics was calculated by the Darcy model.