We have investigated nitrogen doping effects on the structure and crystallinity of bamboo-shaped multiwalled carbon nanotubes (BS-MWNTs) by means of x-ray photoemission spectroscopy (XPS) and transmission electron microscopy. By controlling the NH3/C2H2 flow ratio during the chemical vapor deposition, the nitrogen concentrations of 0.4% to 2.4% were obtained. According to the XPS measurements, the increasing nitrogen concentration gave rise to an increase of the N-sp3 C bonds as well as the deterioration of the crystallinity of the BS-MWNTs. Besides, the N-sp3 C bonds were found to prevail over the N-sp2 C bonds above 5% nitrogen concentration. At higher nitrogen concentrations, the BS-MWNTs showed shorter compartment distances, presumably due to the suppressed surface diffusion of carbon on the catalyst particles.

Direct 3d printing for functional modules and their assembly into an integrated microfluidic device.

Sensors with autonomous self-healing properties offer enhanced durability, reliability, and stability. Although numerous self-healing polymers have been attempted, achieving sensors with fast and reversible recovery under ambient conditions with high mechanical toughness remains challenging. Here, a highly sensitive wearable sensor made of a robust bio-based supramolecular polymer that is capable of self-healing via hydrogen bonding is presented. The integration of carbon fiber thread into a self-healing polymer matrix provides a new toolset that can easily be knitted into textile items to fabricate wearable sensors that show impressive self-healing efficiency (>97.0%) after 30 s at room temperature for K+/Na+ sensing. The wearable sweat-sensor systemcoupled with a wireless electronic circuit board capable of transferring data to a smart phonesuccessfully monitors electrolyte ions in human perspiration noninvasively in real time, even in the healed state during indoor exercise. Our smart sensors represent an important advance toward futuristic personalized healthcare applications.

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