Switching the handedness, or the chirality, of a molecule is of great importance in chemistry and biology, as molecules of different handedness exhibit dramatically different physiological properties and pharmacological effects. Here we experimentally demonstrate handedness switching in metamaterials, a new class of custom-designed composites with deep subwavelength building blocks, in response to external optical stimuli. The metamolecule monolayer flips the ellipticity and rotates the polarization angle of light in excess of 10° under optical excitation, a much stronger electromagnetic effect than that of naturally available molecules. Furthermore, the experimentally demonstrated optical switching effect does not require a structural reconfiguration, which is typically involved in molecular chirality switching and is inherently slow. The handedness switching in chiral metamolecules allows electromagnetic control of the polarization of light and will find important applications in manipulation of terahertz waves, such as dynamically tunable terahertz circular polarizers and polarization modulators for terahertz radiations.

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Carboxymethyl cellulose (CMC) is one of the most promising cellulose derivatives. Due to its characteristic surface properties, mechanical strength, tunable hydrophilicity, viscous properties, availability and abundance of raw materials, low-cost synthesis process, and likewise many contrasting aspects, it is now widely used in various advanced application fields, for example, food, paper, textile, and pharmaceutical industries, biomedical engineering, wastewater treatment, energy production, and storage energy production, and storage and so on. Many research articles have been reported on CMC, depending on their sources and application fields. Thus, a comprehensive and well-organized review is in great demand that can provide an up-to-date and in-depth review on CMC. Herein, this review aims to provide compact information of the synthesis to the advanced applications of this material in various fields. Finally, this article covers the insights of future CMC research that could guide researchers working in this prominent field.

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A major challenge in optics is how to deliver and concentrate light from the micron-scale into the nano-scale. Light can not be guided, by conventional mechanisms, with optical beam sizes significantly smaller than its wavelength due to the diffraction limit. On the other hand, focusing of light into very small volumes beyond the diffraction limit can be achieved by exploiting the wavelength scalability of surface plasmon polaritons. By slowing down an optical wave and shrinking its wavelength during its propagation, optical energy can be compressed and concentrated down to nanometer scale, namely, nanofocusing. Here, we experimentally demonstrate and quantitatively measure the nanofocusing of surface plasmon polaritons in tapered metallic V-grooves down to the deep subwavelength scale - approximately lambda/40 at wavelength of 1.5 micron - with almost 50% power efficiency.

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Monodisperse cyclic poly(oxyethylene) (CPOE) was synthesized from linear dihydroxy-terminated poly(oxyethylene) (LPOE) with molecular weights from 400 to 1500 g/mol. Blends of CPOE with LPOE were prepared and examined with pulsed-field-gradient (PFG) 1 H NMR and rheology to determine the self-diffusion coefficient (D) and zero-shear viscosity (η) in the melt. Single average diffusion coefficients were measured for all blends. For blends prepared from components with equivalent molecular weights >400 g/mol, the D's are suppressed and the η's are enhanced in comparison with predictions based on binary mixing rules. This is attributed to topological threading of rings onto linear chains. Blends of perdeuterated LPOE with hydrogenous CPOE (1500 g/mol) were prepared and examined with PFG NMR. The resulting D's, representing only the CPOE in the blends, are smaller than the average D's measured for the fully hydrogenous blends at a given composition, indicating that complete averaging of the component molecular dynamics does not occur in these binary blends. Extrapolation to zero CPOE concentration yielded the trace D for 1500 g/mol CPOE in LPOE (2.8 × 10 -12 m 2 /s at 56°C). This trace D, assumed characteristic of threaded conformations, was used with the pure-component D's and a three-term mixing rule to determine the percentage of rings threaded as a function of CPOE concentration. The results are in qualitative and quantitative agreement with published modeling studies.