Chitosan-coated magnetic nanoparticles (CMNP) were obtained at 70 °C and 80 °C in a one-step method, which comprises precipitation in reverse microemulsion in the presence of low chitosan concentration in the aqueous phase. X-ray diffractometry showed that CMNP obtained at both temperatures contain a mixture of magnetite and maghemite nanoparticles with ≈4.5 nm in average diameter, determined by electron microscopy, which suggests that precipitation temperature does not affect the particle size. The chitosan coating on nanoparticles was inferred from Fourier transform infrared spectrometry measurements; furthermore, the carbon concentration in the nanoparticles allowed an estimation of chitosan content in CMNP of 6%–7%. CMNP exhibit a superparamagnetic behavior with relatively high final magnetization values (≈49–53 emu/g) at 20 kOe and room temperature, probably due to a higher magnetite content in the mixture of magnetic nanoparticles. In addition, a slight direct effect of precipitation temperature on magnetization was identified, which was ascribed to a possible higher degree of nanoparticles crystallinity as temperature at which they are obtained increases. Tested for Pb2+ removal from a Pb(NO3)2 aqueous solution, CMNP showed a recovery efficacy of 100%, which makes them attractive for using in heavy metals ion removal from waste water.

This article deals with the plasma-surface modification of cellulose nanocrystals and their employment as reinforcement additive of ABS.

Syntheses of biolestomers through the coordination polymerization of terpenes, such as ocimene (Oc), β-myrcene (My) andtrans-β-farnesene (Fa), using catalyst systems based on neodymium versatate (NdV3) are reported in this work. All polymerization products were characterized by size exclusion chromatography, differential scanning calorimetry and nuclear magnetic resonance in order to determine their macromolecular, thermal and structural characteristics. The NdV3in combination with diisobutylaluminum hydride as cocatalyst and diethylaluminum chloride (DEAC) as halogen source was found effective for Oc polymerizations providing polyocimenes with molecular weights (Mn) in the order of 20 to 57 Kg/mol, broad molecular weight distributions (Mw/Mn) since 3.8 until 8.2, preferablycis-1,4 content (61-69 %) and glass transition temperatures (Tg) in the range of-30 to-26 °C. On the other hand, the same NdV3but now activated by modified methylaluminoxane and DEAC was found considerably active in My and Fa polymerizations, affording polymyrcenes and polyfarnesenes withMnbetween 155 and 243 Kg/mol, as well asMw/Mnranging between 3.1-3.9 and 1,4 content values were found higher than 94 % for this subfamily of polyterpenes, being the 3,4 content the complement for completing 100 %. Moreover, it was demonstrated thatTgof polyterpenes studied depends on the size of pendant group, shifting it towards lower temperatures as increasing the size of the pendant group.

In this work, we report the fabrication of self-assembled zinc oxide nanorods grown on pentagonal faces of silver nanowires by using microwaves irradiation. The nanostructures resemble a hierarchal nanoantenna and were used to study the far and near field electrical metal-semiconductor behavior from the electrical radiation pattern resulting from the phase map reconstruction obtained using off-axis electron holography. As a comparison, we use electric numerical approximations methods for a finite number of ZnO nanorods on the Ag nanowires and show that the electric radiation intensities maps match closely the experimental results obtained with electron holography. The time evolution of the radiation pattern as generated from the nanostructure was recorded under radio frequency signal stimulation, in which the generated electrical source amplitude and frequency were varied from 0 to 5 V and from 1 to 10 MHz, respectively. The phase maps obtained from electron holography show the change in the distribution of the electric radiation pattern for individual nanoantennas. The mapping of this electrical behavior is of the utmost importance to gain a complete understanding for the metal-semiconductor (Ag/ZnO) heterojunction that will help to show the mechanism through which these receiving/transmitting structures behave at nanoscale level.

Arrays of metallic thermocouples in the shape of spiral nanoantennas are proposed as infrared detectors, which use the thermoelectric properties of the metallic interfaces to generate electrical DC signals. The responsivity of these types of antennas is evaluated from both theoretical and numerical perspectives pointing out its potential as infrared sensors. Moreover, the same structures can be used to characterize the state of polarization of the optical near fields with a spatial resolution comparable to the wavelength.