Single-ion-conducting nanocomposite polymer electrolytes based on PEG400 and anionic nanoparticles: Part 2. Electrical characterization

Molecular relaxation and polarization phenomena of twelve single-ion-conducting nanocomposite polymer electrolytes (nCPEs) are studied using Broadband Electrical Spectroscopy (BES). The electrolytes are obtained by combining PEG400 oligomers with increasing amounts of anionic nanofiller comprised of fluorinated-TiO₂ associated with Li⁺ cations (LiFT^®), resulting in [PEG400/(LiFT)_y] systems with 0 ≤ y ≤ 26.4. This new class of [PEG400/(LiFT)_y] electrolytes allows us to achieve a significant single-ion conductivity (1.1·10⁻⁵ S cm⁻¹ at 30 °C for n_Li/n_O = 0.113) without the addition of lithium salts. To the best of our knowledge, this is the highest conductivity value reported for this class of electrolytes. This study, in conjunction with the results reported in Part 1, leads us to hypothesize a conduction mechanism in terms of two types of long-range charge-transfer processes. The first charge-transfer occurs at the interface between the filler nanoparticles and filler-PEG domains, while the second occurs through the PEG400 matrix with the assistance of polymer segmental motion. The measured Li⁺ transference numbers confirm that the studied materials are single-ion conductors.     

Effect of subcritical CO2 on the structural and electrical properties of ORMOCERS-APE systems based on Zr and Al

Two series of hybrid inorganic-organic polymer electrolytes of the organically modified ceramics as polymer electrolytes (ORMOCERS-APE) type with formulas {Al[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n (1.85 ≤ ρ ≤ 2.24, 0 ≤ z ≤ 1.06) and {Zr[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n (1.80 ≤ ρ ≤ 1.99, 0 ≤ z ≤ 0.90) were treated with CO₂ in subcritical conditions (293 K and 5 MPa). The effect of CO₂ on the samples was investigated by using ESEM, thermal analysis (TG and DSC) and broad band dielectric spectroscopy (BDS).Both complexes {Al[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n and {Zr[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n after CO₂ treatment exhibited a change in the segmental relaxation with respect to the untreated samples. This phenomenon has been interpreted in terms of higher portion of free volume in the samples. The CO₂ treatment primarily lowered the conductivity of {Al[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n complexes of about one order of magnitude, as opposed to {Zr[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n complexes, where an increment of two orders of magnitude was observed. In both cases the conductivity of the treated and untreated materials versus the reciprocal absolute temperature presents the typical Vogel-Tamman-Fulcher (VTF) behavior. The different effects on the conductivities of the treated complexes are explained in terms of the modified anion-trapping ability of Al centers and in terms of the interactions of subcritical CO₂ with the host polymer and the salt. Insight about the conductivity mechanisms were provided by the study of the VTF parameters and the relaxation times determined from the Debye peaks of the imaginary resistivity, the imaginary permittivity and the correlated motion analysis.     

Opening Doors to Future Electrochemical Energy Devices: The Anion‐Conducting Polyketone Polyelectrolytes

The numerous potential benefits of incorporating anion‐exchange membranes (AEMs), in place of proton‐exchange membranes (PEMs), in energy storage and conversion technologies renders their development of fundamental importance for the continued evolution of alternative energy systems. However, the widespread implementation of AEMs is currently plagued by a range of problems including lower conductivity (with respect to PEMs), poor stability, and high cost. This study reports the conversion of polyketone, one of the world's most mass produced and cheap polymers, to a new highly tuneable polymer architecture, functionalized polyketone (FPK), that demonstrates a range of excellent properties rendering it a significant prospect for AEM materials. The thermal, processing, and ion‐conducting properties of FPK are governed by the amount and nature of the newly formed N‐substituted pyrrole pendant side groups. At 80 °C, the quarternized pyridyl FPK derivative (4MPyrFPK) yields ion‐conductivities of 8.6 and 10.5 mS cm^?1 in the iodide and hydroxide forms. In addition, the hydroxide form of 4MPyr‐FPK demonstrates remarkable stability toward the typically problematic alkaline conditions. No chemical decomposition is observed to the membrane after imbibing it in KOH solution for 72 h, and furthermore, the ion‐conductivity is demonstrated to remain constant for at least 30 d at 80 °C.     

Chemical modification and structural rearrangements of polyketone‐based polymer membrane

Alternating polyketones constitute a very interesting class of polymers, which can be modified for the preparation of functional polymers. The chemical modification of polyketone using 1,2‐diaminopropane was used to prepare a conductive membrane. This paper is focused on the synthesis and structural rearrangements of polyamine for preparing anion‐exchange membranes by the solvent casting technique. According to the Paal‐Knorr mechanism, 1,4‐dicarbonyl of polyketone reacts with 1,2‐diaminopropane to form a pyrrole ring along the polyketone backbone. In addition, the so‐modified polyamines can undergo structural rearrangements to form N‐substituted pyrrole crosslinked with dihydropyridine units. The conversion degree and the N content are quite low. The pathway reactions have been proposed on the basis of ¹H‐NMR, ultraviolet–visible, and Fourier transform infrared results. Scanning electron microscopy, differential scanning calorimetry, and X‐ray diffraction techniques were used to study the morphological, thermal, and structural characteristics of the modified polyketone, as well as the correspondoing membrane. The experimental results indicated that the membrane is a potential candidate for energy conversion technology. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45485.     

Production of lipid microparticles containing bioactive molecules functionalized with PEG

The functionalization of bioactive principles is a relevant issue as it allows increasing their stability, to raise the hydrophilic properties of hydrophobic materials, to reduce the absorption from macrophages and the proteolytic degradation. For this reason, we have functionalized a model protein (Ribonuclease A) with polyethylene glycol (PEG₅₀₀₀).We have investigated the production of lipid/PEG particles incorporating this active principle by a supercritical fluid technology (particles from gas saturated solution, PGSS) to obtain solid micro- and nanoparticles.Runs were carried out to study the process conditions; thus, the effects of the operative variables, such as temperature, pressure and organic solvent, were optimized to obtain micrometric particles.The particles produced were characterized by static light scattering (SLS) to determine their mean and distribution size. The better operative conditions were employed to produce microparticles incorporating Ribonuclease A (RNAse) as both native and PEGylated form.The BCA test was applied to determine the maximum amount of protein incorporated in the particles and the in vitro release. The retained enzymatic activity of proteins after the PEGylation and after the micronization process was also determined by spectrophotometric evaluation.     

Iodide-conducting plastic crystals based on N,N-dimethyl-2-(methylsilyloxy) ethanaminium cations (MESEA) for application in dye-sensitized solar cells

This report describes the synthesis and the properties of twelve iodide-conducting Plastic Crystal Electrolytes (PCEs) based on N,N-dimethyl-2-(methylsilyloxy) ethanaminium cations (MESEAⁿ⁺) and I⁻/I₃⁻ anions for application in dye-sensitized solar cells (DSSCs).     

New corrosion cast media and its ability for SEM and light microscope investigation

SEM of corrosion casts (CC) provides the opportunities to study the vessels and ducts in the phyllogenetic and ontogenetic (age‐related) settings, as well as the pathogenesis, compensation, and sanogenesis in different diseases and experimental models. Along with the refinement of SEM CC, the requirements toward casting media (CM) as nontoxicity, low viscosity, quick polymerization, resistance to corrosion solutions, availability, and so on, gradually has developed. We aimed to adapt the sets widely used in dental practice toward the modern requirements to the CC. The following ratio of the components of Protacryl‐M and Aycryl‐C sets were used for the preparation CM—0.25 g MAYCRYL Powder +0.08 g Benzoyl Peroxide +5.0 ml Protacryl‐M liquid component +0.2 Redont Colour (dye concentrate). The obtained solidifying mass was injected in the blood vessels and biliary ducts of the adult Wistar white rats. The SEM of CC of different organs’ vascular networks, as well as a biliary tract, reveals that offered CM excellently replicates the forms and branching features of studied tubular structures of all sizes and gives the adequate imprinting of their luminal surfaces. Besides, CM may provide the replication of perivascular spaces and give the casts having no analogous in the appropriate literature. The CM prepared by us perfectly reproduces all possibilities of famous rubbers widely used for the casting of different vascular–ductular structures. Besides, it presents the new implications, which should be implemented in the profound research of the connective‐tissue skeleton of different organs.     

Method for optimizing coating properties based on an evolutionary algorithm approach

In industry as well as many areas of scientific research, data collected often contain a number of responses of interest for a chosen set of exploratory variables. Optimization of such multivariable multiresponse systems is a challenge well suited to genetic algorithms as global optimization tools. One such example is the optimization of coating surfaces with the required absolute and relative sensitivity for detecting analytes using devices such as sensor arrays. High-throughput synthesis and screening methods can be used to accelerate materials discovery and optimization; however, an important practical consideration for successful optimization of materials for arrays and other applications is the ability to generate adequate information from a minimum number of experiments. Here we present a case study to evaluate the efficiency of a novel evolutionary model-based multiresponse approach (EMMA) that enables the optimization of a coating while minimizing the number of experiments. EMMA plans the experiments and simultaneously models the material properties. We illustrate this novel procedure for materials optimization by testing the algorithm on a sol-gel synthetic route for production and optimization of a well studied amino-methyl-silane coating. The response variables of the coating have been optimized based on application criteria for micro- and macro-array surfaces. Spotting performance has been monitored using a fluorescent dye molecule for demonstration purposes and measured using a laser scanner. Optimization is achieved by exploring less than 2% of the possible experiments, resulting in identification of the most influential compositional variables. Use of EMMA to optimize control factors of a product or process is illustrated, and the proposed approach is shown to be a promising tool for simultaneously optimizing and modeling multivariable multiresponse systems.     

In vivo measurement of unattached radon progeny deposited in the human respiratory tract

Seven nose breathing and seven mouth breathing volunteers were exposed to atmospheres enriched with unattached radon progeny (218Po, 214Pb and 214Bi). The activity of these radionuclides deposited in the respiratory tract was measured in vivo after the exposures. The results of these measurements are in agreement with predictions calculated with the ICRP Publication 66 Human Respiratory Tract Model. Temporal analysis of the activity deposited in the heads of the volunteers leads to the conclusion that a significant amount of the deposited activity associated with particle diameters of about 1 nm is not subject to a fast transport to the gastrointestinal tract as generally reported for larger aerosol particles.     

Single-ion-conducting nanocomposite polymer electrolytes based on PEG400 and anionic nanoparticles: Part 1. Synthesis,structure and properties

The synthesis and the properties of single-ion-conducting nanocomposite polymer electrolytes (nCPEs) are described. The nCPEs are obtained by doping polyethylene glycol 400 (PEG400) with different amounts of a fluorinated TiO₂-based nanofiller (LiFT^®) that is surface-functionalized with Li⁺ cations. Electrolytes with general formula [PEG400/(LiFT)_y] and y = n_Ti/n_PEG ranging from 0 to 26.4 are obtained. The materials are characterized by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Fourier-Transform Infrared Spectroscopy in both the medium (FT-MIR) and far infrared (FT-FIR). In the [PEG400/(LiFT)_y] electrolytes the concentration of LiFT nanofiller strongly affects the thermal stability and transitions of PEG400. In addition, vibrational measurements allow us to reveal the interactions occurring between: (a) different PEG400 chains; (b) PEG400 and Li⁺ cations; and (c) PEG400 and LiFT nanoparticles (NPs). On LiFT nanofiller concentration, results show three compositional regions in [PEG400/(LiFT)_y] electrolytes which are correlated to the presence of three different interaction environments between LiFT NPs and PEG400 chains.