The contribution of carbon nanotubes as the building block of high-frequency electronic devices has received much interest due to their favorable characteristics. This Review focuses on the electromagnetic properties (see image) of individual as well as multiple- and single-walled carbon-nanotube arrangements primarily aimed at microwave, millimeter-wave, and THz electronics applications.

Direct imaging of water/air/solid interfaces: A “droplet-inside-view” method based on MAC-mode AFM and force–volume function is introduced to directly characterize the microscopic details of a three-phase interface. Researches of the Cassie state, the quasi-Wenzel state, and the transition of the two states for lotus leaves show (see image) that microscopic wetting behavior dominates the macroscopic wettability of micro-/nanoscale interfaces.

Formation of biopolymer-stabilized nanosuspensions followed by dextranase enzyme treatment is demonstrated for the liberation of monodisperse particles of controllable size up to 6 nm (see image). A range of metal oxide nanoparticles stabilized by remnant oligomer at ≈3 wt% are reliably prepared for applications that include catalysis and nanoparticle-based biosensors.

Structured polymer brushes are readily prepared by AFM lithography and show improved mechanical properties over structured polymer films obtained on spin-coated films by using the same method. The figure shows an array of 200-nm-diameter pillars obtained on a 30-nm-thick polystyrene brush by cross writing of single scan lines.

An atomic force microscopy topograph with a long and narrow (≈24 µm × 37 nm) graphene nanoribbon emerging from a graphite flake laying on a silicon oxide substrate is shown in the image. The sample is prepared by microcleavage using silicone stamps instead of cellophane tape. These nanoribbons present well-defined edges along the graphite crystallographic directions.

A dual-scale metal transfer technique is presented to generate metal patterns with two different length scales from a single master. An adhesive polymer layer is brought in contact with the metal-coated surface in two sequential steps to transfer metal layers from both ridges and valleys of the mold aided by the difference in adhesive force (see image).

Size-tuned thiol-capped bismuth telluride nanoparticles (see image) are synthesized and annealed to make phase-pure nanostructured material. These materials exhibit relatively high thermoelectric power and unusually low temperature-independent thermal conductivity, the latter due to phonon scattering.

Size (and position) matters: Site-controlled InGaAs quantum dots (QDs) of high homogeneity are grown on (111)B GaAs substrates patterned with submicrometer inverted pyramids (see AFM images). The strong dependence of the QD emission energy, E_QD, on the pyramids' position and size is investigated, and the possibility of using this dependence to fine-tune E_QD is discussed.

Electrospun nanoparticle–nanofiber composites (see image) are fabricated via a one-step synthesis wherein the electrospun polymer acts as both a reducing agent for the metal salt precursor and a protecting and templating agent for the ensuing nanoparticles. The in situ reduction is done under ambient conditions and is free of organic solvents and separate chemical reducers and stabilizers.

A useful tip: Tip-enhanced Raman spectroscopy reveals a wealth of chemical and structural information on a polymer-blend thin film with high lateral and depth resolution (see picture). The location of the polymers and local differences in the thickness of the films, as well as nanopores at the subsurface of the polymer film are detected.

The dispersion/precipitation process of gold nanocrystals in near-critical fluids (NcFs) can be fine-tuned by discrete variations in the fluid density and is largely dependent upon nanoparticle size. Larger nanocrystal cores lose dispersibility faster as density is decreased. The results show that size-selective transport, separation, and deposition of nanocrystals are possible in NcFs by choosing the appropriate solvent and density range (see image).

Polymeric nanoparticles containing a fluorescent dye and a photochromic spiropyran are prepared via a facile one-step miniemulsion polymerization (see image). UV and visible light can be applied to reversibly “switch on” and “switch off” the fluorescence emission of the fluorescent dye through the intraparticle fluorescence resonance energy-transfer process.