Increase In Ion Concentration Research Articles

Randomised study of intra-oral kinetics of fluoride-containing toothpastes

ObjectivesThis randomised, controlled, analyst blind, crossover study aimed to evaluate and compare salivary fluoride and calcium ion concentration over 60 min following brushing with an assigned treatment and following an orange juice (OJ) or deionised (DI) water rinse 60 min post-brushing. MethodsStudy treatments, both containing 1150 ppm fluoride as NaF and 5% w/w KNO3, were the Test (including 1.2 % w/w cocamidopropyl betaine) and Comparator (including tetrasodium pyrophosphate and sodium lauryl sulphate) toothpastes. Twenty nine participants were randomised to treatment. ResultsA sharp increase in salivary fluoride ion concentration immediately post-brushing with either toothpaste decreased over time. Fluoride concentration following Test toothpaste use was numerically higher than the Comparator at all timepoints, with a significant difference from 10 min post-brushing (p < .05). Following the 60 min rinse, there were no significant differences between the Test or Comparator + OJ groups in salivary fluoride concentration but the Test + DI water group was significantly lower than Test (p < .001) or Comparator (p < .001) + OJ groups. A reduction in salivary calcium ion concentration was seen immediately post-brushing and after the OJ rinse with both toothpastes. Significant differences were observed in favour of the Test toothpaste at all timepoints (p < .05) and for Test and Comparator + OJ group (p < .001) compared with Test + DI water rinse. Both treatments were generally well-tolerated. ConclusionsThis study demonstrated that toothpaste formulations with identical declared fluoride concentrations and the same fluoride source give rise to differing intraoral fluoride concentrations over time, which are potentially related to different formulation excipient effects. Clinical significanceBy understanding the interaction of toothpaste formulation excipients in the oral environment, formulations can be developed that maximise retention of fluoride in the oral environment.

Influence of zeta potential of ZrO2 and Al2O3 nanoparticles on removal of metal ions by hybrid electrospun polyamide 6 membrane: Kinetics of adsorption and fouling mechanisms

AbstractElectrostatic charging of the adsorbent is a critical method for the selective removal of metal ions fromacidic wastewater. In this study, electrospun polyamide 6 (PA6) membranes were separately incorporated with Al2O3 and ZrO2 nanoparticles (NPs), and their ability in the removal of cations (eg, Al3+ and Fe3+) were evaluated by static adsorption and filtration methods. The impact of various parameters, namely microstructure, surface porosity, functional molecular groups, and hydrophobicity of membranes on the removal process, was investigated. By evaluating the zeta (ζ) potential of oxide ceramic NPs, it was found that the Al2O3 and ZrO2 NPs had positive and negative electrostatic charges inacidic solution, respectively. The results showed that the incorporation of negatively charged ZrO2 NPs improved both the static adsorption and filtration removal capability of the PA6 membrane. The maximum adsorption efficiency of Al3+ and Fe3+ cations was 52.43% and 54.11%, and the highest filtration efficiency of the mentioned cations obtained by electrospun hybrid ZrO2 incorporated PA6 membrane was 98.6% and 99.3%, respectively. It was also found that the adsorption of both Al3+ and Fe3+ cations correlated well with the pseudo‐second‐order kinetic model. The results also demonstrated that the dominant blocking models were switched with the increase in the initial concentration of metal ions from 5 ppm‐70 ppm.

Effects of pozzolanic reaction on carbonation degree and strength of steel slag compacts containing zeolite

In this paper, a novel method, zeolite partially replacing steel slag, was proposed to futher improve the properties (compressive strength and carbonation degree) of steel slag compacts futher after CO2 curing. Inductively coupled plasma (ICP) results illustrated that the Ca, and, Fe ion concentrations in the steel slag matrix substituted by 5 wt% zeolite (water-to-solid ratio of 10) were 78.19 mg/L and 4.09 mg/L, 19.3% and 99.0% higher than that of pure steel slag after 1 d of hydration curing respectively. The decreased crystallite size of C4AF and increase in Fe ion concentration illustrates that zeolite with pozzolanic properties could react with CaO-FeOX matrix components such as brownmillerite (C4AF), to produce C-S-H gel, which possesses higher solubility than the CaO-FeOX matrix, to improve the Ca ion concentration. In terms of the compressive strength and carbonation degree results, the optimum zeolite substitution ratios were 5 wt% and 15 wt%, respectively. After 1 d hydration and 2 h of carbonation curing, the compressive strength of the steel slag compacts with 5 wt% zeolite (CSZ5) was 14% higher than that of pure steel slag compacts (CSZ0). With respect to carbonation degree, the steel slag substituted with 15 wt% zeolite (CSZ15) had a 10.2% higher carbonation level than that of CSZ0.

Evaluation of genotoxicity and cytotoxicity, metal ion release induced by metals from orthodontic appliances – An in vivo study

Aim: To estimate the concentration of metal ions (Ni, Cr, Fe and Co), cytotoxicity and genotoxicity of buccal mucosal cell in patients being treated with fixed orthodontic appliances. Materials and Methods: A total of 50 patients aged between 14-30 years of age were included in the study. Three samples of buccal cells were collected from each orthodontic patient at the following times: T (0) – before insertion of the appliance, T (1) – 3 months after insertion of the appliance, T (2) – 6 months after insertion of the appliance. Metal ion concentration of buccal cells was evaluated using atomic absorption spectrophotometer (AAS). The buccal cells were also evaluated for genotoxicity (DNA damage) and cytotoxicity (cellular viability) using alkaline comet assay and tryphan blue exclusion dye test respectively. Results: It was noted that there was a significant (p&lt;0.001) increase in the metal ion concentrations in the buccal cell sample. The comet assay results showed significant DNA damage in the buccal cells whereas the cellular viability showed a decrease over the study period but the decrease was insignificant. Conclusion: The buccal mucosa cells of patients treated with fixed orthodontic appliances over a period of six months showed significant increases in nickel, chromium, iron and cobalt content, with significant DNA damage and insignificant decrease in cellular viability. Further studies should be carried out to evaluate the effects of these changes over the course of the treatment.

Terbium-functionalized silica nanoparticles for metal ion sensing by fluorescence quenching

We describe preparation of a new luminescent material based on silica nanoparticles functionalized with terbium (Tb3+) complex of a polyamino polycarboxylic chelator, which displayed fluorescence when dispersed in aqueous and organic solvents. The functionalized material, TbL@SiO2, was firstly characterized by FTIR, UV–Vis and photoluminescent (PL) measurements. Further, it was used for various metal ions sensing as monitored by fluorescence quenching, indicating the highest decrease for iron(III), copper(II) and cobalt(II) metal ions. The calculated Stern-Volmer constants (KSV) equalled 2.21 × 105 M−1 for Fe3+, 6.81 × 105 M−1 for Cu2+ and 9.26 × 105 M−1 for Co2+, while the resulted lower detection limits reached 0.17 μM, 0.10 μM and 0.13 μM for Fe3+, Cu2+ and Co2+ respectively. In addition, the quenching mechanism was investigated through lifetime measurements which revealed a dynamic nature upon increase of the transition metal ion concentration. This was evidenced by changes in the emission lifetime (from τ0 = 1600 μs to τq = 1102 μs, thus a decrease of 31% in lifetime in presence of 8.6 μM Cu2+), most probably due to the collision interactions that affected the energy transfer of the ligand towards terbium ions.

The gravistimulation-induced very slow Ca2+ increase in Arabidopsis seedlings requires MCA1, a Ca2+-permeable mechanosensitive channel

Gravity is a critical environmental factor affecting the morphology and function of plants on Earth. Gravistimulation triggered by changes in the gravity vector induces an increase in the cytoplasmic free calcium ion concentration ([Ca2+]c) as an early process of gravity sensing; however, its role and molecular mechanism are still unclear. When seedlings of Arabidopsis thaliana expressing apoaequorin were rotated from the upright position to the upside-down position, a biphasic [Ca2+]c-increase composed of a fast-transient [Ca2+]c-increase followed by a slow [Ca2+]c-increase was observed. We find here a novel type [Ca2+]c-increase, designated a very slow [Ca2+]c-increase that is observed when the seedlings were rotated back to the upright position from the upside-down position. The very slow [Ca2+]c-increase was strongly attenuated in knockout seedlings defective in MCA1, a mechanosensitive Ca2+-permeable channel (MSCC), and was partially restored in MCA1-complemented seedlings. The mechanosensitive ion channel blocker, gadolinium, blocked the very slow [Ca2+]c-increase. This is the first report suggesting the possible involvement of MCA1 in an early event related to gravity sensing in Arabidopsis seedlings.

Saltwater corrosion behaviour of equal channel angular pressed AZ80/91 Mg alloys

In this study, AZ80/91 Mg alloys were used to comprehend the electrochemical corrosion behaviour of coarse-grained and fine-grained Mg alloys in different concentration of NaCl solution as well as in the marine environment. The inadequate studies of the corrosion response of ECAPed AZ80 and AZ91 Mg alloy in a different environment were noticed. Accordingly, the current research presents and compares the corrosion behaviour of AZ80/91 Mg alloys in 2.5 wt% NaCl, 3.5 wt% NaCl solution and Natural Sea Water. Influence of corrosion media on coarse and fine-grained AZ80/91 Mg alloys was discussed in the results and discussion section. Corrosion attack of AZ80/91 Mg alloys under the above environment, increased with increase in chloride ion concentration and decreased with the ECAP passes.

Analysis of the Mechanical Properties and Mechanism of Zinc Ion‐Contaminated Red Clay

To study the effects of different concentrations of zinc ions on the mechanical strength, material composition, and microstructure of red clay, a triaxial test, an x‐ray diffraction test, an x‐ray fluorescence spectrometry test, a scanning electron microscopy test, and a mercury intrusion test were carried out on contaminated soil to investigate the mechanisms of zinc ion‐contaminated red clay. The results show that the higher the concentration of zinc ions, the smaller the shear strength and cohesion of the red clay. The internal friction angle is increased first and then decreased. From material composition, zinc ion makes montmorillonite and hemite disappear in red clay. With the increase of zinc ion concentration, quartz semiquantitative increase and kaolinite semiquantitative decrease and the content of SiO2, Fe2O3, and Na2O reduces. Microscopically, the structure of red clay changes from floc structure to granular and aggregate structure after the zinc ions are added, while the contact of the particles is converted to point contact. With the increase of the concentration of zinc ions, the porosity and the fractal dimension of the red clay gradually increase, and the stability of the granular structure is weakened.

Effect of natural additives on concrete mechanical properties

The construction industry commonly uses steel-reinforced concrete despite the high levels of pollution in its production process. In this research, it was studied the dossing effect of nopal mucilage and Ixtle fiber as additives for the enhancement of concrete’s mechanical properties: compression strength, flexural strength, heat transfer coefficient, ultrasonic pulse rate, ED-XRF, and roughness by fractal dimension analysis. It was found a remarkable improvement in mechanical properties when both natural additives are used. It was observed an increase of potassium and calcium ions concentration after additive dosing. This behavior determines the suitability of the blend for its application in the engineering and construction industry to reduce cement or steel use.

Influence of li1+ (alkali metal) ion on structural, optical and magnetic properties of nickel ferrite nanomaterials for multifunctional applications

Lithium substituted nickel ferrite nanoparticles, LixNi1-xFe2O4 (x = 0 and 0.5) synthesized using citrate precursor method at a low annealing temperature of 550 °C. The effect of Lithium on structural, morphology, magnetic and optical properties of nanoparticles has been studied. X-ray diffraction measurements show the formation of cubic spinal crystal. The crystallite size were evaluated by Williamson-Hall plot and found to be 26 nm and 24 nm respectively. Monotonically increase in lattice constant and lattice strain was observed with the substitution of Lithium atom. FTIR measurements show, two characteristics absorption peaks of cubic spinel ferrites at range around 580 cm−1 and 470 cm−1 wave number. Morphology of the sample was studied using Scanning Electron Microscopy and found change in agglomeration due to change in antiparticle interaction. The Indirect band gap were found 2.20 eV for Nickel ferrite and 2.28 eV for substituted Li ferrite. Photoluminescence spectra show that strong luminescence in visible range. Magnetic parameter such as remanence, coercivity, and saturation magnetization increases with increase in lithium ion concentration (Mr- 7.57 emu/g- 14.478 emu/g, Hc −178Oe-192Oe and (36.5 emu/g to 41.5 emu/g). Force constant and bond length were found to dependent on Lithium ion. Thus prepared Lithium substituted ferrite nanomaterials possess pure phase crystal, uniform growth in magnetism with luminescence in visible ranges, which can be useful for multifunctional applications in various areas of science and technology.

Bubbles: The Good, the Bad, and the Ugly

Bubbles are bad news for electrolysis due to undesired overpotentials, though their impact may be even further reaching than previously understood. In a recent report in Energy & Environmental Science, Kempler and researchers control the microstructure of electrodes to minimize overpotentials caused by bubbles in a photoelectrochemical cell.

Electric energies of a charged sphere surrounded by electrolyte

<abstract> By using the recently generalized version of Newton's Shell Theorem <xref ref-type="bibr" rid="b6">[6]</xref> analytical equations are derived to calculate the electric potential energy needed to build up a charged sphere, and the field and polarization energy of the electrolyte inside and around the sphere. These electric energies are calculated as a function of the electrolyte's ion concentration and the radius of the charged sphere. The work needed to build up the charged sphere, <italic>E_CC</italic> (i.e. the total charge-charge interaction energy) decreases with increasing ion concentration of the electrolyte because of the electrolyte ions' increasing screening effect on the charge-charge interaction. The work needed to build up the charged sphere appears as a sum of the field and polarization energy of the electrolyte. At zero ion concentration the electrolyte's field energy is equal with <italic>E_CC</italic> while the polarization energy is zero. At high electrolyte ion concentrations (<italic>C</italic> &gt; 10<italic>mol</italic>/<italic>m</italic>³) 50% of <italic>E_CC</italic> appears as the polarization energy of the electrolyte, 25% as the electrolyte's field energy inside the sphere and 25% as the electrolyte's field energy around the sphere. </abstract>

Effect of copper slag fine aggregate on corrosion processes and behavior in reinforced concrete prism specimen

This paper reports the result of experimental on the resistance to chloride diffusion and steel corrosion of concrete mixtures. A series of tests were performed to investigate the effect of copper slag as partial replacement of fine aggregate on corrosion processes and behavior in prism specimens. Chloride migration tests in steady-state were executed at the age of 28 and 91 days in accordance with Japan Society of Civil Engineers (JSCE) G571-2003 to determine the diffusion coefficient of chloride ions permeated through concrete specimens. In addition, some electrochemical tests were carried out through the repeated wet and dry (NaCl 10%) cycles up to 1 year to examines the probability of corrosion of steel bars in concrete, corrosion current density, and the rate of oxygen permeability. Based on the chloride migration test, which was obtained from the cumulative increase of chloride ion concentration, the results indicate that concrete with a longer curing period achieved lower chloride-ion concentration, thus suggesting that there is an increase in the resistance of concrete against chloride attack. The chloride penetration depth and distribution of chloride content in CUS prism specimens after exposure to wet and dry cycles for one year are almost similar to those of the OPC specimens. Thus, the durability performance of CUS concretes with respect to the resistance against chloride ingress was comparable to that of OPC concrete. Besides that, it is generally recognized that the incorporation of fly ash in blended cement by its the pozzolanic reaction of fly ash improves concrete protection against chloride-induced corrosion of steel bars by reducing its diffusivity and the rate of oxygen permeability.

Alterations in Hemolymph Ion Concentrations and pH in Adult Daphnia magna in Response to Elevations in Major Ion Concentrations in Freshwater.

Increases in the concentrations of major ions (Na+ , K+ , Ca2+ , Mg2+ , Cl- ) in freshwater are a growing concern for ecosystem health. These increases may originate from anthropogenic activities such as road deicing, fracking spills, mining, and fertilizer application and have detrimental effects on freshwater organisms through disturbances in ionoregulation and acid-base balance. The cladoceran Daphnia magna is adapted for active ion uptake and reduction of ion loss to maintain osmotic balance, but alterations in ionic composition of the environmental water are associated with toxicity. In the present study, hemolymph ion concentrations were measured using ion-selective microelectrode techniques. Increases in the hemolymph concentrations of Na+ and K+ correspond to elevations in the concentrations of these ions in ambient water. Water concentrations associated with sustained increases in hemolymph ion concentrations correlate well with median lethal concentration values from previous toxicology studies, indicating that Na+ and K+ concentrations in hemolymph may predict toxicity. When water K+ concentration is increased, a simultaneous increase in water Na+ concentration mitigates the increase in hemolymph K+ concentration, a finding which is consistent with the reported mitigation of K+ toxicity by Na+ . When ambient concentrations of K+ , Na+ , and Cl- are increased, not only is there a rise in hemolymph ion concentration but hemolymph pH is altered and pH regulation appears to be prioritized over regulation of hemolymph Na+ , K+ , and Cl- in D. magna. Environ Toxicol Chem 2021;40:366-379. © 2020 SETAC.

Differential Impact of Salinity Stress on Seeds Minerals, Storage Proteins, Fatty Acids, and Squalene Composition of New Quinoa Genotype, Grown in Hyper-Arid Desert Environments.

The effects of climate change and soil salinization on dryland ecosystems are already widespread, and ensuring food security is a crucial challenge. In this article, we demonstrate changes in growth performance and seed quality of a new high-yielding quinoa genotype (Q5) exposed to sodium chloride (NaCl), sodium sulfate (Na2SO4), and mixed salts (NaCl + Na2SO4). Differential responses to salt stress in growth performance, seed yield, and seed quality were identified. High salinity (mixed Na2SO4 + NaCl) reduces plant height by ∼30%, shoot and root dry weights by ∼29%, head panicle length and panicle weight by 36–43%, and seed yield by 37%, compared with control conditions. However, the 1,000-seed weight changes insignificantly under salinity. High content of essential minerals, such as Fe, Zn, and Ca in quinoa Q5 seeds produced under salinity, gives the Q5 genotype a remarkable advantage for human consumption. Biomarkers detected in our studies show that the content of most essential amino acids is unchanged under salinity. The content of amino acids Pro, Gly, and Ile positively correlates with Na+ concentration in soil and seeds, whereas the content of squalene and most fatty acids negatively correlates. Variation in squalene content under increasing salinity is most likely due to toxic effects of sodium and chlorine ions as a result of the decrease in membrane permeability for ion movement as a protective reaction to an increase in the sodium ion concentration. Low squalene accumulation might also occur to redirect the NADPH cofactor to enhance the biosynthesis of proline in response to salinity, as both syntheses (squalene and proline) require NADPH. This evidence can potentially be used by the food and pharmaceutical industries in the development of new food and health products.

Photocatalytic Studies of La,Ce Co-Doped ZnO Nanoparticles

Zinc oxide nanoparticles were co-doped with varying concentrations of lanthanum (La) and cerium (Ce) ions using co-precipitation method. The resulting powders were calcined in a muffle furnace for 1 h at a temperature of 500°C to produce La,Ce-doped ZnO nanoparticles of varying stoichiometry viz. (Zn0.98La0.01Ce0.01O, Zn0.96La0.02Ce0.02O, Zn0.94La0.03Ce0.03O, and Zn0.92La0.04Ce0.04O). This method of co-doping is cost effective and does not require any complex procedure, equipment or inert gases. The synthesized samples were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) to study the size, phases and grain morphology. XRD patterns revealed the hexagonal wurtzite phase of the synthesized samples. The average size of the undoped and La,Ce co-doped ZnO nanoparticles, as calculated from XRD pattern, was found to be 25 nm. Further, the size of co-doped nanoparticles decreased significantly with increasing dopant concentration. Optical properties were studied through UV-Visible spectrophotometry. The photocatalytic activities of undoped and La,Ce co-doped ZnO nanoparticles were examined by observing the decomposition of Rhodamine B dye under UV lamp within 0–80 min. The Rhodamine B (RB) dye solution was efficiently photo-degraded within 35 min when using Zn0.92La0.04Ce0.04O as catalyst, mechanism of which has been thoroughly discussed below. Further, photoluminescence (PL) studies revealed the narrowing of band gap with increase in concentration of dopant ions as indicated by the red shift in the PL emission spectrum of co-doped nanoparticles.

Gap junctions amplify spatial variations in cell volume in proliferating tumor spheroids

Sustained proliferation is a significant driver of cancer progression. Cell-cycle advancement is coupled with cell size, but it remains unclear how multiple cells interact to control their volume in 3D clusters. In this study, we propose a mechano-osmotic model to investigate the evolution of volume dynamics within multicellular systems. Volume control depends on an interplay between multiple cellular constituents, including gap junctions, mechanosensitive ion channels, energy-consuming ion pumps, and the actomyosin cortex, that coordinate to manipulate cellular osmolarity. In connected cells, we show that mechanical loading leads to the emergence of osmotic pressure gradients between cells with consequent increases in cellular ion concentrations driving swelling. We identify how gap junctions can amplify spatial variations in cell volume within multicellular spheroids and, further, describe how the process depends on proliferation-induced solid stress. Our model may provide new insight into the role of gap junctions in breast cancer progression.

Synthesis and luminescence properties of Eu3+ doped potassium titano telluroborate (KTTB) glasses for red laser applications

A novel series of europium doped potassium titano telluroborate (Eu3+: KTTB) glasses were prepared with the melt quenching and characterized with XRD, SEM, FTIR, UV–Vis–NIR spectrometer, PL etc. And their bonding parameter (δ), the Judd-Ofelt (J-O) parameters, as well as the radiative parameters such as the stimulated emission cross-section, the lifetime and the quantum efficiency, were calculated, evaluated and analysed. The results show that their density, refractive index, and field strength increase with Eu3+ ion concentration. Both X-ray diffraction pattern and SEM image represent the amorphous nature of the glasses. The δ values of the samples are positive, and increases with Eu3+ ion concentration. The optical band gap decreases with increase of Eu3+ ion concentration, while the Urbach energy value keeps increase. The J-O parameters for all the samples follow the same trend as Ω2> Ω4> Ω6, and both Ω2 and Ω4 increase first then decrease with Eu3+ ion concentration, 2EuKTTB glass possesses the highest Ω2 (8.05 × 10–20cm2) value. The emission spectra exhibit five peaks in the visible region centering around 579, 591, 613, 652 and 700 nm, respectively, in which the red emission at 613 nm from 5D0→7F2 transition has the highest intensity increasing with Eu3+ ion concentration increase from 0.1 to 2 wt. % then decreasing at higher concentration. The colour coordinates dominate the reddish region of the CIE 1931 diagram, showing that the glasses are potentially suitable for red laser and colour display device applications. The asymmetric intensity ratio (AIR) and correlated colour temperature (CCT) has been also evaluated, both of which increase first and then decrease with Eu3+ ion concentration and almost get their maximum at the doped 2 wt. %. The decay time of 5D0 metastable state to the lower state exhibits single exponential nature. The lifetime decreases with Eu3+ ion concentration, while the quantum efficiency η (%) increases first but decreases after the doped 2 wt. %. 2EuKTTB glass is of the highest value of either the stimulated emission cross-section (7.55 × 10–22 cm2) or the quantum efficiency (90.1 %) among all the glasses.

Metal and Phosphate Ions Show Remarkable Influence on the Biomass Production and Lipid Accumulation in Oleaginous Mucor circinelloides.

The biomass of Mucor circinelloides, a dimorphic oleaginous filamentous fungus, has a significant nutritional value and can be used for single cell oil production. Metal ions are micronutrients supporting fungal growth and metabolic activity of cellular processes. We investigated the effect of 140 different substrates, with varying amounts of metal and phosphate ions concentration, on the growth, cell chemistry, lipid accumulation, and lipid profile of M. circinelloides. A high-throughput set-up consisting of a Duetz microcultivation system coupled to Fourier transform infrared spectroscopy was utilized. Lipids were extracted by a modified Lewis method and analyzed using gas chromatography. It was observed that Mg and Zn ions were essential for the growth and metabolic activity of M. circinelloides. An increase in Fe ion concentration inhibited fungal growth, while higher concentrations of Cu, Co, and Zn ions enhanced the growth and lipid accumulation. Lack of Ca and Cu ions, as well as higher amounts of Zn and Mn ions, enhanced lipid accumulation in M. circinelloides. Generally, the fatty acid profile of M. circinelloides lipids was quite consistent, irrespective of media composition. Increasing the amount of Ca ions enhanced polyphosphates accumulation, while lack of it showed fall in polyphosphate.

The role of ionic clusters in the determination of the properties of partially neutralized ethylene-acrylic acid ionomers

Ionomers with different degree of neutralization were prepared from an ethylene-acrylic acid copolymer of 8.5 wt% acrylic acid content. The ionomers were characterized by Fourier transform infrared spectroscopy, small angle X-ray scattering, differential scanning calorimetry and dynamic mechanical thermal analysis measurements as well as rheology and tensile testing. The main relaxing species in ionomers are the methylene groups and the ethylene-acrylic acid copolymer segments. The mobility of these latter decreases upon neutralization and above a critical degree of neutralization a phase consisting of polyethylene segments attached to ionic clusters forms. The crystalline structure of the polymer contains primary and secondary crystallites. The amount and regularity, i.e. lamella thickness, of the latter decrease with increasing neutralization. Multiplets form from ionic species already at a small degree of neutralization and then they associate into clusters with increasing size as ion content increases. The mechanical properties of the ionomers are determined by their crystalline structure and cluster formation. Clusters increase strength and modulus, while decrease deformability. The combined effect of the two factors (crystallinity, cluster size) on stiffness was successfully described by a simple model.