Carbon nanotube sponges are synthesized by chemical vapor deposition, in which nanotubes are self‐assembled into a three‐dimensionally interconnected framework. The sponges are very light, highly porous, hydrophobic in pristine form, and can be elastically and reversibly deformed into any shape. The sponges can float on water surfaces and absorb large‐area spreading oil films (see images), suggesting promising environmental applications.

A facile solvent-exchange strategy is devised to fabricate anti-drying, self-healing and transparent organohydrogels for stretchable humidity sensing applications.

Development of sorbent materials with high selectivity and sorption capacity, easy collection and recyclability is demanding for spilled oil recovery. Although many sorption materials have been proposed, a systematic study on how they can be reused and possible performance degradation during regeneration remains absent. Here we report magnetic carbon nanotube sponges (Me-CNT sponge), which are porous structures consisting of interconnected CNTs with rich Fe encapsulation. The Me-CNT sponges show high mass sorption capacity for diesel oil reached 56 g/g, corresponding to a volume sorption capacity of 99%. The sponges are mechanically strong and oil can be squeezed out by compression. They can be recycled using through reclamation by magnetic force and desorption by simple heat treatment. The Me-CNT sponges maintain original structure, high capacity, and selectivity after 1000 sorption and reclamation cycles. Our results suggest that practical application of CNT macrostructures in the field of spilled oil recovery is feasible.

Ionic hydrogels, a class of intrinsically stretchable and conductive materials, are widely used in soft electronics. However, the easy freezing and drying of water-based hydrogels significantly limit their long-term stability. Here, a facile solvent-replacement strategy is developed to fabricate ethylene glycol (Eg)/glycerol (Gl)-water binary antifreezing and antidrying organohydrogels for ultrastretchable and sensitive strain sensing within a wide temperature range. Because of the ready formation of strong hydrogen bonds between Eg/Gl and water molecules, the organohydrogels gain exceptional freezing and drying tolerance with retained deformability, conductivity, and self-healing ability even stay at extreme temperature for a long time. Thus, the fabricated strain sensor displays a gauge factor of 6, which is much higher than previously reported values for hydrogel-based strain sensors. Furthermore, the strain sensor exhibits a relatively wide strain range (0.5−950%) even at −18 °C. Various human motions with different strain levels are monitored by the strain sensor with good stability and repeatability from −18 to 25 °C. The organohydrogels maintained the strain sensing capability when exposed to ambient air for nine months. This work provides new insight into the fabrication of stable, ultrastretchable, and ultrasensitive strain sensors using chemically modified organohydrogel for emerging wearable electronics.

No abstract

Porous carbon nanotube networks represent a type of material that can achieve both structural robustness and high flexibility. We demonstrate here controlled synthesis of soft to hard sponges with densities ranging from 5 to 25 mg/cm(3), while retaining a porosity of >99%. The stable sponge-like structure allows excellent compressibility tunable up to 90% volume shrinkage, and the ability to recover most of volume by free expansion. Electrical resistivity of the sponges changes linearly and reversibly after 300 cycles of large-strain compression. Nanotubes forming the three-dimensional scaffold maintain good contact and percolation during large-strain deformation, polymer infiltration, and cross-linking process, suggesting potential applications as strain sensors and conductive nanocomposites.

Nanotube–Si heterojunction solar cells are fabricated by coating a thin film of double‐walled carbon nanotubes on n‐type silicon wafers. These solar cells show power‐conversion efficiencies in the range of 5–7%. The nanotubes perform multiple functions in the cells, including charge separation, charge transport, and charge collection.

Flexible pressure sensors are of great importance to be applied in artificial intelligence and wearable electronics. However, assembling a simple structure, high-performance capacitive pressure sensor, especially for monitoring the flow of liquids, is still a big challenge. Here, on the basis of a sandwich-like structure, we propose a facile capacitive pressure sensor optimized by a flexible, low-cost nylon netting, showing many merits including a high response sensitivity (0.33 kPa) in a low-pressure regime (<1 kPa), an ultralow detection limit as 3.3 Pa, excellent working stability after more than 1000 cycles, and synchronous monitoring for human pulses and clicks. More important, this sensor exhibits an ultrafast response speed (<20 ms), which enables its detection for the fast variations of a small applied pressure from the morphological changing processes of a droplet falling onto the sensor. Furthermore, a capacitive pressure sensor array is fabricated for demonstrating the ability to spatial pressure distribution. Our developed pressure sensors show great prospects in practical applications such as health monitoring, flexible tactile devices, and motion detection.