Reactive dissolution and its effects on electrical conduction, morphological change and chemical transformation in thin fi lms of Mg, AZ31B Mg alloy, Zn, Fe, W, and Mo in de-ionized (DI) water and simulated body fl uids (Hanks' solution pH 5-8) are systematically studied, to assess the potential for use of these metals in water-soluble, that is, physically "transient", electronics. The results indicate that the electrical dissolution rates in thin fi lms can be much different that traditionally reported corrosion rates in corresponding bulk materials. Silicon metal oxide fi eld effect transistors (MOSFETs) built with these metals demonstrate feasibility for use in transient electronics.

We report a simple and effective way of fabricating high-quality carbon nanoscrolls (CNSs), using isopropyl alcohol solution to roll up monolayer graphene predefined on SiO(2)/Si substrates. Transmission electron microscopy studies reveal that the CNS has a tube-like structure with a hollow core surrounded by graphene walls 0.35 nm apart. Raman spectroscopy studies show that the CNS is free of significant defects, and the electronic structure and phonon dispersion are slightly different from those of two-dimensional graphene. Finally, the CNS-based device is fabricated, directly on the SiO(2)/Si substrate. Electrical-transport measurements show that its resistance is weakly gate-dependent but strongly temperature-dependent. In addition, the CNS can sustain a high current density up to 5 x 10(7) A/cm(2), indicating that it is a good candidate for microcircuit interconnects. The controlled fabrication of high-quality CNSs may open up new opportunities for both fundamental and applied research of CNSs.

We use time-domain thermoreflectance (TDTR), and the generation and detection of longitudinal and surface acoustic waves, to study the thermal conductivity, heat capacity, and elastic properties of thin films of poly­(vinyl alcohol) (PVA), poly­(acrylic acid) (PAA), polyacrylamide (PAM), poly­(vinyl­pyrrolidone) (PVP), methyl cellulose (MC), poly­(4-styrene­sulfonic acid) (PSS), poly­(N-acryloyl­piperidine) (PAP), poly­(methyl methacrylate) (PMMA), and a polymer blend of PVA/PAA. The thermal conductivity of six water-soluble polymers in the dry state varies by a factor of ≈2, from 0.21 to 0.38 W m–1 K–1, where the largest values appear among polymers with a high concentration of hydrogen bonding (PAA, PAM, PSS). The longitudinal elastic constants range from 7.4 to 24.5 GPa and scale linearly with the shear elastic constants, suggesting a narrow distribution of Possion’s ratio 0.35 < ν < 0.40. The thermal conductivity increases with the average sound velocity, as expected based on the model of the minimum thermal conductivity. The thermal conductivity of polymer blends of PVA (0.31 W m–1 K–1) and PAA (0.37 W m–1 K–1) is in agreement with a simple rule of mixtures.

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