Quantification of diffusion coefficient distribution (DCD) and correlation with molecular weight distribution (MWD) of polymers is still an issue in pulsed field-gradient nuclear magnetic resonance (PFG-NMR). The conventional scaling law utilized so far to relate diffusion coefficient and molecular weight only holds true for the determination of MWD at sufficiently low concentrations. To extend measurement limits and to get a good signal-to-noise ratio, an exponential correlation is introduced to describe the effect of polymer concentration on diffusion in PFG-NMR. Two model polymers (polystyrene and poly(methyl methacrylate)) dissolved in deuterated chloroform are studied at different concentrations in the range of 0.16-8 wt%. The DCDs are determined by modeling the measured signal attenuation with three methods (gamma distribution, log normal distribution, and tailored norm regularization). It is shown that the proposed method applies to the PFG-NMR measurements on polymer solutions over a wide concentration range, providing almost the same MWDs as those obtained at low concentrations. The MWDs retrieved from NMR experiments agree well with those by size exclusion chromatography.

We present a study of the radial structure of a spherical polyelectrolyte brushes by anomalous small-angle X-ray scattering. The spherical polyelectrolyte brushes consist of a solid poly(styrene) core of ca. 100 nm diameter onto which long linear chains of poly(acrylic acid) (PAA) are densely grafted. A sufficiently high pH, these polyelectrolyte chains are fully charged. Rubidium ions are used as counterions because their adsorption edge (15 199.6 eV) can be conventiently reached by synchrotron radiation. By performing small-angle X-ray scattering studies at different energies of the incident radiation, the contribution of the Rb + counterions can be analyzed separately. The scattering contribution of the counterions can be derived and compared to the scattering intensity of the entire particle. The distributions of the macro-ion and of the counterions are shown to be very similiar. This shows that the counterions must be confined within the brush.

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A newly developed high frequency spark provides a green, sustainable and versatile platform for manufacturing diverse sub-10 nm particles with well-defined chemical composition that serve as key building blocks.

A major challenge in nanotechnology is that of determining how to introduce green and sustainable principles when assembling individual nanoscale elements to create working devices.For instance, textile nanofinishing is restricted by the many constraints of traditional pad-drycure processes, such as the use of costly chemical procedures to produce nanoparticles (NPs), the high liquid and energy consumption, the production of harmful liquid waste, and multi-step batch operations. By integrating low-cost, scalable, and environmentally benign aerosol processes of the type proposed here into textile nanofinishing, these constraints can be circumvented while leading to a new class of fabrics. The proposed one-step textile nanofinishing process relies on the diffusional deposition of aerosol NPs onto textile fibers. As proof of this concept, we deposit Ag NPs onto a range of textiles and assess their antimicrobial properties for two strains of bacteria (i.e., Staphylococcus Aureus and Klebsiella Pneumoniae).The measurements show that the logarithmic reduction in bacterial count reaches ca. 5.5 (corresponding to a reduction efficiency of 99.96%) when the Ag loading is one order of magnitude less (10 ppm; i.e., 10 mg Ag NPs per kg of textile) than in the textiles treated by traditional wet-routes. The antimicrobial activity does not increase in proportion to the Ag content above 10 ppm as a consequence of a "saturation" effect. Such low loading for

Using the magnetocaloric effect in nanoparticles holds great potential for efficient refrigeration and energy conversion. The most promising candidate materials for tailoring the Curie temperature to room temperature are rare-earth-based magnetic nanoalloys. However, only few high-nuclearity lanthanide/transition-metal nanoalloys have been produced so far. Here we report, for the first time, the observation of magnetic response in spark-produced LaFeSi nanoalloys. The results suggest that these nanoalloys can be used to exploit the magnetocaloric effect near room temperature; such a finding can lead to the creation of unique multicomponent materials for energy conversion, thus helping toward the realization of a sustainable energy economy.

Superabsorbent polymer (SAP) hydrogels have pronounced water‐absorbing and water‐storing capacities, which are essential for numerous potential applications. It remains a challenge to better understand the network topology because of their amorphous and anisotropic structures. Synthesis parameters such as monomer concentration, degree of neutralization and crosslinking, and surface crosslinking are varied to correlate structural changes in the network with low‐field proton double‐quantum (1H DQ) NMR results. 1H DQ‐NMR data are processed by a reliable, user‐independent analysis approach to determine the fractions of network defects, of mobile sol components, and of network chains as well as the residual dipolar coupling distribution in SAPs. In addition, results obtained by applying different distributions to describe the DQ buildup curves are quantified and compared. The correlation between topological and synthesis parameters as well as the impact of temperature, swelling, and solvent of SAP on DQ signals is investigated and discussed.

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