Dependence of PSS Diffusion in Multilayers of Entangled PDADMA on Temperature and Salt Concentration: More than One Diffusion Constant

<div> <div> <div> <p>The model and analysis methods developed in this work are generally applicable to any polymer electrolyte/cation-anion combination, but we focus on the currently most prominent polymer electrolyte material system: poly(ethylene) oxide/Li- bis(trifluoromethane) sulfonamide (PEO + LiTFSI). The obtained results are surprising and challenge the conventional understanding of ionic transport in polymer electrolytes: the investigation of a technologically relevant salt concentration range (1 - 4 M) revealed the central role of the anion in coordinating and hindering Li ion movement. Our results provide insights into correlated ion dynamics, at the same time enabling rational design of better PEO-based electrolytes. In particular, we report the following novel observations. 1. Strong binding of the Li cation with the polymer competes with significant correlation of the cation with the salt anion. 2. The appearance of cation-anion clusters, especially at high concentration. 3. The asymmetry in the composition (and therefore charge) of such clusters; specifically, we find the tendency for clusters to have a higher number of anions than cations.</p> </div> </div> </div>

Download Full-text

Effect of High Salt Concentration on Ion Clustering and Transport in Polymer Solid Electrolytes: a Molecular Dynamics Study of PEO-LiTFSI

10.26434/chemrxiv.6294941 ◽

2018 ◽

Author(s):

Nicola Molinari ◽

Jonathan P. Mailoa ◽

Boris Kozinsky

Keyword(s):

Polymer Electrolyte ◽

Salt Concentration ◽

Rational Design ◽

Material System ◽

Ion Dynamics ◽

High Concentration ◽

Anion Clusters ◽

Poly Ethylene Oxide ◽

Poly Ethylene

<div> <div> <div> <p>The model and analysis methods developed in this work are generally applicable to any polymer electrolyte/cation-anion combination, but we focus on the currently most prominent polymer electrolyte material system: poly(ethylene) oxide/Li- bis(trifluoromethane) sulfonamide (PEO + LiTFSI). The obtained results are surprising and challenge the conventional understanding of ionic transport in polymer electrolytes: the investigation of a technologically relevant salt concentration range (1 - 4 M) revealed the central role of the anion in coordinating and hindering Li ion movement. Our results provide insights into correlated ion dynamics, at the same time enabling rational design of better PEO-based electrolytes. In particular, we report the following novel observations. 1. Strong binding of the Li cation with the polymer competes with significant correlation of the cation with the salt anion. 2. The appearance of cation-anion clusters, especially at high concentration. 3. The asymmetry in the composition (and therefore charge) of such clusters; specifically, we find the tendency for clusters to have a higher number of anions than cations.</p> </div> </div> </div>

Download Full-text

Effects of Red Pepper, Salt-Fermented Anchovy Extracts and Salt Concentration on the Tastes of Kimchi

Journal of the Korean Society of Food Science and Nutrition ◽

10.3746/jkfn.2003.32.3.346 ◽

2003 ◽

Vol 32 (3) ◽

pp. 346-349 ◽

Cited By ~ 8

Keyword(s):

Salt Concentration ◽

Red Pepper

Download Full-text

Synthesis and conformation of sequential basic polypeptides with branched and linear side chains

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19852925 ◽

1985 ◽

Vol 50 (12) ◽

pp. 2925-2936 ◽

Cited By ~ 2

Author(s):

Štěpánka Štokrová ◽

Jan Pospíšek ◽

Jaroslav Šponar ◽

Karel Bláha

Keyword(s):

Amino Acid ◽

Salt Concentration ◽

Salt Solution ◽

Theoretical Work ◽

Side Chain ◽

Amino Acid Residues ◽

Cd Spectra ◽

Low Salt ◽

Conformational Freedom ◽

Basic Polypeptides

Polypeptides (Lys-X-Ala)n and (Lys-X-Gly)n in which X represents residues of isoleucine and norleucine, respectively, and polypeptide (Tle-Lys-Ala)n, were synthesized via polymerization of 1-hydroxysuccinimidyl esters of the appropriate tripeptides to complete previously studied series. Circular dichroism (CD) spectra of the respective polymers were measured as a function of pH and salt concentration of the medium. The results were correlated with those obtained previously with the same series containing different amino acid residues at the X-position. The helix forming ability of the polypeptides (Lys-X-Ala)n with linear X side chain was found to be independent of the length. In the series (Lys-X-Gly)n the unordered conformation was the most probable one except (Lys-Ile-Gly)n. This polymer assumed the β conformation even in low salt solution at neutral pH. An agreement with some theoretical work concerned with the restriction of conformational freedom of amino acid residue branching at Cβ atom with our experimental results is evident.

Download Full-text

Temperature and concentration dependence of equivalent conductivity in Ca(NO3)2-CaI2-H2O system

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19801639 ◽

1980 ◽

Vol 45 (6) ◽

pp. 1639-1645 ◽

Cited By ~ 1

Author(s):

Jindřich Novák ◽

Ivo Sláma

Keyword(s):

Linear Function ◽

Concentration Dependence ◽

Mole Fraction ◽

Constant Temperature ◽

Salt Concentration ◽

Free Water ◽

Water Molecules ◽

Equivalent Conductivity ◽

Calcium Salts ◽

Fraction I

The dependence of the equivalent conductivity on the temperature and composition of the Ca(NO3)2-CaI2-H2O system was studied. The ionic fraction [I-]/([I-] + [NO-3]) was changed from 0.1 to 0.5, the mole fraction of calcium salts (assumed in anhydrous form in the presence of free water molecules) was 0.075-0.200. The equivalent conductivity was found to be a linear function of the ionic fraction at constant temperature and salt concentration.

Download Full-text

Diffusion

10.1093/oso/9780198753919.003.0014 ◽

2018 ◽

Author(s):

Ginestra Bianconi

Keyword(s):

Random Walks ◽

Spectral Properties ◽

Diffusion Constant ◽

Network Structures ◽

Multilayer Networks ◽

Multilayer Network ◽

Lévy Walk ◽

Number Of Layers ◽

Levy Walk ◽

Speed Up

This chapter addresses diffusion, random walks and congestion in multilayer networks. Here it is revealed that diffusion on a multilayer network can be significantly speed up with respect to diffusion taking place on its single layers taken in isolation, and that sometimes it is possible also to observe super-diffusion. Diffusion is here characterized on multilayer network structures by studying the spectral properties of the supra-Laplacian and the dependence on the diffusion constant among different layers. Random walks and its variations including the Lévy Walk are shown to reflect the improved navigability of multilayer networks with more layers. These results are here compared with the results of traffic on multilayer networks that, on the contrary, point out that increasing the number of layers could be detrimental and could lead to congestion.

Download Full-text

Bottlebrush polymers in the melt and polyelectrolytes in solution share common structural features

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1916362117 ◽

2020 ◽

Vol 117 (10) ◽

pp. 5168-5175 ◽

Cited By ~ 4

Author(s):

Joel M. Sarapas ◽

Tyler B. Martin ◽

Alexandros Chremos ◽

Jack F. Douglas ◽

Kathryn L. Beers

Keyword(s):

Neutron Scattering ◽

Correlation Length ◽

Salt Concentration ◽

Polymer Concentration ◽

Structural Features ◽

Peak Position ◽

Correlation Peak ◽

Grafting Density ◽

Scattering Measurements ◽

Polyelectrolyte Solutions

Uncharged bottlebrush polymer melts and highly charged polyelectrolytes in solution exhibit correlation peaks in scattering measurements and simulations. Given the striking superficial similarities of these scattering features, there may be a deeper structural interrelationship in these chemically different classes of materials. Correspondingly, we constructed a library of isotopically labeled bottlebrush molecules and measured the bottlebrush correlation peak position q*=2π/ξ by neutron scattering and in simulations. We find that the correlation length scales with the backbone concentration, ξ∼cBB−0.47, in striking accord with the scaling of ξ with polymer concentration cP in semidilute polyelectrolyte solutions (ξ∼cP−1/2). The bottlebrush correlation peak broadens with decreasing grafting density, similar to increasing salt concentration in polyelectrolyte solutions. ξ also scales with sidechain length to a power in the range of 0.35–0.44, suggesting that the sidechains are relatively collapsed in comparison to the bristlelike configurations often imagined for bottlebrush polymers.

Download Full-text

GERMINATION AND VIGOUR IN SEEDS OF THE COWPEA IN RESPONSE TO SALT AND HEAT STRESS

Revista Caatinga ◽

10.1590/1983-21252019v32n115rc ◽

2019 ◽

Vol 32 (1) ◽

pp. 143-151 ◽

Cited By ~ 1

Author(s):

Luma Rayane de Lima Nunes ◽

Paloma Rayane Pinheiro ◽

Charles Lobo Pinheiro ◽

Kelly Andressa Peres Lima ◽

Alek Sandro Dutra

Keyword(s):

Salt Stress ◽

Heat Stress ◽

High Temperature ◽

Low Temperature ◽

Vigna Unguiculata ◽

Salt Concentration ◽

Dry Weight ◽

Germination Percentage ◽

Different Types ◽

Different Temperatures

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.

Download Full-text