We show that by using an original method, bulk graphite can be bonded onto borosilicate glass or potentially any insulating substrate with ionic conductivity and then cleaved off to leave single or few layer graphene on the substrate, identified optically and with Raman spectroscopy. This simple, inexpensive and fast method leads to the preparation of large area graphene and single or few-layer films of layered materials in general. We have prepared mm size few-layer graphene samples and also measured I-V characteristics in a FET. This opens up perspectives both for fundamental research as well as for applications.
A rational
design of adsorbents with high uptake efficiency and fast kinetics
for highly toxic pollutants is a key challenge in environmental remediation.
Here, we report the design of a well-defined thioether-crown-rich
porous calix[4]arene-based mesoporous polymer S-CX4P and
its utility in removal of highly relevant toxic mercury (Hg2+) from water. The polymer shows an exceptional, record-high uptake
efficiency of 1686 mg g–1 and the fastest initial
adsorption rate of 278 mg g–1 min–1. Remarkably, S-CX4P can effectively remove Hg2+ from high concentration (5 ppm) to below the acceptable limit for
drinking water (2 ppb) even in the presence of other competitive metals
at high concentrations. In addition, the polymer can be easily regenerated
at room temperature and reused multiple times with negligible loss
in uptake rate and efficiency. The results demonstrate the potential
of rationally designed thioether-crown-rich polymers for high performance
mercury removal.
A parallel array of isolated metal nanowires is expected to be hydrophilic. We show, however, that a clustering of such nanowires brought about by vacuum drying produces a 'dual-scale roughness' and confers a strongly hydrophobic property to the surface. The mean size of the nanowire clusters as well as the contact angle are both found to be related to the wire length, and the critical wire length above which the surface becomes hydrophobic is ≈10 µm. Surface roughness is generally known to enhance water-repellent properties, but this is the first report of roughness-induced hydrophobicity on a bare (uncoated) metallic surface.
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