Devices made from stretchable electronic materials could be incorporated into clothing or attached directly to the body. Such materials have typically been prepared by engineering conventional rigid materials such as silicon, rather than by developing new materials. Here, we report a class of wearable and stretchable devices fabricated from thin films of aligned single-walled carbon nanotubes. When stretched, the nanotube films fracture into gaps and islands, and bundles bridging the gaps. This mechanism allows the films to act as strain sensors capable of measuring strains up to 280% (50 times more than conventional metal strain gauges), with high durability, fast response and low creep. We assembled the carbon-nanotube sensors on stockings, bandages and gloves to fabricate devices that can detect different types of human motion, including movement, typing, breathing and speech.
Complex permittivity was obtained on glycerol, xylitol, sorbitol and sorbitol-xylitol mixtures in the supercooled liquid state in the frequency range between 10 microHz and 500 MHz at temperatures near and above the glass transition temperature. For all the materials, a dielectric relaxation process was observed in addition to the well-known structural alpha and Johari-Goldstein beta relaxation process [G. P. Johari and M. Goldstein, J. Chem. Phys. 53, 2372 (1970)]. The relaxation time for the new process is always larger than that for the alpha process. The relaxation time shows non-Arrhenius temperature dependence with correlation to the behavior of the alpha process and it depends on the molecular size systematically. The dielectric relaxation strength for the new process shows the effect of thermal history and decreases exponentially with time at a constant temperature. It can be considered that a nonequilibrium dynamics causes the new process.
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