Single-walled carbon nanotubes (SWCNTs) exhibit strong antibacterial activities. Direct contact between bacterial cells and SWCNTs may likely induce cell damages. Therefore, the understanding of SWCNT-bacteria interactions is essential in order to develop novel SWCNT-based materials for their potential environmental, imaging, therapeutic, and military applications. In this preliminary study, we utilized atomic force microscopy (AFM) to monitor dynamic changes in cell morphology and mechanical properties of two typical bacterial models (gram-negative Escherichia coli and gram-positive Bacillus subtilis) upon incubation with SWCNTs. The results demonstrated that individually dispersed SWCNTs in solution develop nanotube networks on the cell surface, and then destroy the bacterial envelopes with leakage of the intracellular contents. The cell morphology changes observed on air dried samples are accompanied by an increase in cell surface roughness and a decrease in surface spring constant. To mimic the collision between SWCNTs and cells, a sharp AFM tip of 2 nm was chosen to introduce piercings on the cell surface. No clear physical damages were observed if the applied force was below 10 nN. Further analysis also indicates that a single collision between one nanotube and a bacterial cell is unlikely to introduce direct physical damage. Hence, the antibacterial activity of SWCNTs is the accumulation effect of large amount of nanotubes through interactions between SWCNT networks and bacterial cells.

Two‐dimensional lead and tin halide perovskites were prepared by intercalating the long alkyl group 1‐hexadecylammonium (HDA) between the inorganic layers. We observed visible‐light absorption, narrow‐band photoluminescence, and nanosecond photoexcited lifetimes in these perovskites. Owing to their hydrophobicity and stability even in humid air, we applied these perovskites in the decarboxylation and dehydrogenation of indoline‐2‐carboxylic acids. (HDA)2PbI4 or (HDA)2SnI4 were investigated as photoredox catalysts for these reactions, and quantitative conversion and high yields were observed with the former.

Customized hybrid carbon fiber supercapacitors with energy across two orders and power across four orders of magnitude.

No abstract

Smart textiles are intelligent devices that can sense and respond to environmental stimuli. They require integrated energy storage to power their functions. An emerging approach is to build integratable fiber/yarn-based energy storage devices. Here, we demonstrated all-carbon solidstate yarn supercapacitors using commercially available activated carbon and carbon fiber yarns for smart textiles. Conductive carbon fibers concurrently act as current collectors in yarn supercapacitors and as substrates for depositing large surface area activated carbon particles.Two hybrid carbon yarn electrodes were twisted together in polyvinyl alcohol/H 3 PO 4 polymer gel, which is used as both electrolyte and separator. A 10-cm long yarn supercapacitor, with the optimum composition of 2.2 mg/cm activated carbon and 1 mg/cm carbon fiber, shows a specific length capacitance of 45.2 mF/cm at 2 mV/s, an energy density of 6.5 µWh/cm, and power density of 27.5 µW/cm. Since the yarn supercapacitor has low equivalent series resistance at 4.9 Ω/cm, longer yarn supercapacitors up to 50 cm in length were demonstrated, yielding a high total capacitance up to 1164 mF. The all-carbon solid-state yarn supercapacitors also exhibit excellent mechanical flexibility with minor capacitance decreases upon bending or being crumpled.Utilizing three long yarn supercapacitors, a wearable wristband was knitted; this wristband is capable of lighting up an LED indicator, demonstrating strong potential for smart textile applications.An emerging approach of building energy storage devices for smart textiles is to directly incorporate energy storage materials at the formation stage of textile fibers, and then integrate multiple fibers into energy storage fabrics. Researchers are exploring different nanomaterials for energy storage, such as carbon nanotubes, graphene, and many metal oxide nanoparticles.However, different nanomaterials have their specific weakness which limits their practical applications, for example, the high cost of single walled carbon nanotubes, the lack of scalable production of amorphous Ni(OH) 2 , 1 the potential health and environmental toxicity of RuO 2 and some other carbon nanomaterials. 2-4 Activated carbon derived from biomaterials or polymer precursors is the most widely used electrode material in commercial supercapacitors nowadays.Carbon fibers with excellent electrical conductivity and mechanical strength, made from polyacrylonitrile or pitch, are produced in large quantity with billions of dollars market. We envisage that it is a practical and promising approach to efficiently incorporate activated carbon into weavable/knittable carbon fiber yarns, which combines the good capacitive energy storage property of activated carbon with excellent electrical conductivity and mechanical flexibility of carbon fibers. Yarn supercapacitors can be assembled using such hybrid carbon fibers of activated carbon and carbon fibers as electrodes, which unveil strong potential for smart textile applications in the near future.conducting polymers...