Gas bubbles of nanometer size were produced on atomically flat solid surfaces and imaged by atomic force microscopy (AFM) in tapping mode in water. In AFM images, nanobubbles appeared like bright spheres. Some of the bubbles remained stable for hours during the experiments. The bubbles were disturbed under high load during AFM imaging. A related mechanism is discussed.

Improving the energy output of batteries at sub-zero temperatures is crucial to the long-term application of advanced electronics in extreme environments. This can generally be accomplished by employing high-voltage cathodes, applying Li metal anodes, and improving the electrolyte chemistry to provide facile kinetics at ultralow temperature. However, systems capable of all three of these have seldom been studied. Herein, we demonstrate the design of such a system through solvent fluorination, applying a 1 M LiPF6 in a methyl 3,3,3-trifluoropionate (MTFP)/fluoroethylene carbonate (FEC) (9:1) electrolyte that simultaneously provided high-voltage cathode and Li metal anode reversibility at room temperature. This performance was attributed to the production of fluorine-rich interphases formed in the MTFP-based system, which was investigated by X-ray photoelectron spectroscopy (XPS). Furthermore, the all-fluorinated electrolyte provided 161, 149, and 133 mAh g–1 when discharged at −40, −50, and −60 °C, respectively, far exceeding the performance of the commercial electrolyte. This work provides new design principles for high-voltage batteries capable of ultra-low-temperature operation.

A method has been developed for imaging single-stranded DNA with the atomic force microscope (AFM). phi X174 single-stranded DNA in formaldehyde on mica can be imaged in the AFM under propanol or butanol or in air. Measured lengths of most molecules are on the order of 1 mu, although occasionally more extended molecules with lengths of 1.7 to 1.9 mu are seen. Single-stranded DNA in the AFM generally appears lumpier than double-stranded DNA, even when extended. Images of double-stranded lambda DNA in the AFM show more sharp kinks and bends than are typically observed in the electron microscope. Dense, aggregated fields of double-stranded plasmids can be converted by gentle rinsing with hot water to well spread fields.

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