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An electrode of hydrated tungsten oxide (WO3⋅nH2O) embedded chitosan‐co‐polyaniline (CHIT‐co‐PANI) composite was electrochemically prepared on an indium tin oxide (ITO) coated glass surface using mineral acid as a supporting electrolyte. The resulting CHIT‐co‐PANI/WO3⋅nH2O/ITO electrode was characterized using ultraviolet‐visible spectroscopy (UV‐vis), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and scanning electron microscopy (SEM). The composite electrode exhibited a three‐dimensional nanofibrous structure with the diameter of the nanofibers ranging from 20 to 100 nm. The CHIT‐co‐PANI/WO3⋅nH2O/ITO electrode allowed for the low potential detection of NO2gas in acidic medium. The NO2gas sensing characteristics were studied by measuring change in the current with respect to concentration and time. Using the CHIT‐co‐PANI/WO3⋅nH2O/ITO electrode, NO2gas was detected electrochemically without interference at pH 2.0 and 0.25 V vs. Ag/AgCl. The current of the electrochemical cell with the CHIT‐co‐PANI/WO3⋅nH2O/ITO electrode decreased linearly with an increase in NO2gas concentration in a range from 100 to 500 ppb with a response time of eight seconds.

Poly(ɛ-caprolactone) (PCL)/montmorillonite (MMT) nanocomposites were prepared by in situ ring‐opening polymerization of ɛ‐caprolactone in the presence of MMT modified by hydroxyl‐group containing alkylammonium cation (Cloisite®30B) in a single mode microwave oven. For the polymerization mixtures, plateaus or exothermal peaks were observed in their temperature‐time profiles and can be attributed to the heat‐generating nature of the ring‐opening polymerization. The morphologies of the nanocomposites showed a predominantly exfoliated structure. The mechanical properties of the nanocomposites were evaluated via dynamic mechanical analysis. Compared with that of the recovered PCL matrix, the mechanical properties of the PCL/Cloisite®30B nanocomposites showed obvious improvement.

PLLA-MPEG diblock copolymers with a controlled number‐average molar mass ranging from 7 330 to 117 610 g · mol−1 and an L‐lactide conversion ranging from 65.1 to 97.3% were synthesized effectively in 20 min at 100 °C by MPEG‐initiated ROP of L‐lactide under microwave irradiation. Prolonged microwave irradiation time led to the degradation of the copolymers because the ROP reaction and the thermal degradation reaction occurred simultaneously at the later stage of the reaction process. The differential scanning calorimetric and thermogravimetric study indicated that higher melting temperatures and thermal stability were obtained for PLLA‐MPEG diblock copolymers with longer PLLA segments.

PCL/clay nanocomposites were prepared by microwave‐assisted in situ ROP of ε‐caprolactone in the presence of either unmodified clay (Cloisite® Na+) or clay modified by quaternary ammonium cations containing hydroxyl groups (Cloisite 30B). This PCL showed significantly improved monomer conversion and molecular weight compared with that produced by conventional heating. An intercalated structure was observed for the PCL/Cloisite Na+nanocomposites, while a predominantly exfoliated structure was observed for the PCL/Cloisite 30B nanocomposites. Microwave irradiation proved to be an effective and efficient method for the preparation of PCL/clay nanocomposites.

Poly(L‐lactide)‐block‐poly(ethylene glycol)‐block‐poly(L‐lactide) (PLLA‐PEG‐PLLA) triblock copolymers were synthesized effectively by poly(ethylene glycol) initiated ring‐opening polymerization (ROP) of L‐lactide under microwave irradiation. The products were characterized by 1H NMR, GPC, and DSC. The experimental results have demonstrated that PLLA‐PEG‐PLLA triblock copolymer with a number‐average molar mass of 28 230 g · mol−1and an L‐lactide conversion of 92.4% could be synthesized after the L‐lactide/PEG2000 reaction mixture was irradiated for 3 min at 100 °C. The L‐lactide/PEG feed ratio had a strong influence on the microwave‐assisted ring‐opening polymerization, in which higher L‐lactide/PEG feed ratios led to copolymers with higher molar masses and lower L‐lactide conversions. Prolonged microwave irradiation at 100 °C did not change the molar mass of the copolymers significantly. The DSC study indicated that higher glass transition and melting temperatures were obtained for PLLA‐PEG‐PLLA triblock copolymers with longer PLLA segment length. The synthesis of the triblock copolymers via microwave heating was much faster than via conventional heating.

Summary:Microwave‐assisted ring‐opening polymerization of ε‐caprolactone in the presence of 1‐butyl‐3‐methylimidazolium tetrafluoroborate ionic liquid using zinc oxide as a catalyst is investigated. By adding 30 wt.‐% ionic liquid, poly(ε‐caprolactone) with a weight‐average molar mass of 28 500 g · mol−1is obtained at 85 W for 30 min. The results indicate that the polymerization could be efficiently enhanced in the presence of ionic liquids under microwave irradiation because ionic liquids can effectively absorb microwave energy.

Adipocyte-cancer cell crosstalk plays a key role in tumorigenesis and metastasis. In this issue of Matter, Gu and colleagues applied adipocytes as a drug depot for effective chemotherapy and tumor microenvironment modulation.

To fulfill the increasing demand for radiofrequency (RF) wireless communication capacity for epidermal electronics, stretchable integrated circuits (ICs) in the gigahertz (GHz) range are desirable. Lumped RF inductors, as a key component in RFICs, typically dominate a large portion of the circuit/chip area and therefore make such inductors mechanically stretchable is critical for GHz-frequency stretchable RFICs. Most of the reported stretchable inductors operate in the MHz frequency range. The only GHz stretchable inductor shows a quality factor of about 2, limiting its potential RF applications. Here, stretchable inductors with a high quality factor of Q> 12.6 and resonance operation frequency of fres> 11.6 GHz are demonstrated by combining microspirals with stretchable structures, overcoming all of the shortcomings of previous demonstrations. Furthermore, a stretchable 1.5–2.6 GHz filter with a peak insertion loss of −2.3 dB at 1.8 GHz is developed, showing negligible performance changes under stretching or on the skin to demonstrate the utility in practical wireless applications like GSM and Bluetooth (2.45 GHz) bands. The demonstrations can facilitate multiple GHz epidermal RFICs in the future.

This corrects the article DOI: 10.1038/ncb3530

Polycrystalline GeSn thin films on Si substrates with a Sn composition up to 4.5% have been fabricated and characterized. The crystalline structure, surface morphology, and infrared (IR) absorption coefficient of the annealed GeSn thin films were carefully investigated. It was found that the GeSn thin films with a Sn composition of 4.5% annealed at 450 °C possessed a desirable polycrystalline structure according to X-ray diffraction (XRD) analyses and Raman spectroscopy analyses. In addition, the absorption coefficient of the polycrystalline GeSn thin films in the IR region was significantly better than that of the single crystalline bulk Ge.

Bond-breaking and oxidation occur during broadband ultraviolet light (UV light) illumination of the polyimide film in the air according to spectroscopic analysis. Surface tension and polarity are increased based on the measurements of contact angles. The liquid-crystal (LC) pretilt angles of the rubbed polyimide films are reduced by both unpolarized and polarized UV light illumination. Both the LC alignment and pretilt angle are generated on unrubbed polyimide films through the photoalignment process. The mechanism of photoalignment of LC is discussed.

A numerical simulation of a novel wide viewing angle twisted-nematic liquid crystal display (TN-LCD) structure has been performed. The simulated results indicate that this new structure can provide an excellent gray level separation and a 50 : 1 contrast ratio that extends up to around ±60° along both the vertical (V) and horizontal (H) directions. No reverse image is expected over the ±65°H/±80°V range. No excessively dark or excessively bright images are observed over the entire viewing angle range of the display. The fabrication process to achieve this novel structure is also proposed.