Dielectric water sorption analysis

Penon, M. Giacomelli; Picken, Stephen J.; Wübbenhorst, Michael; Vos, G.; Turnhout, J. van

doi:10.1063/1.2370739

Cited by 14 publications

(7 citation statements)

References 14 publications

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“…We had interpreted this as being due to a hole filling mechanism of water molecules being preponderant at water contents inferior to ∼3 wt %; a result consistent with the comparison shown for the probe accessible volumes in Figure 5. At the time the available experimental data for PMDA‐ODA was rather inconclusive with volume swelling at high RH varying from as much as 2.5% down to negligible values 24, 31, 34, 237. Since then we have carried out our own experimental tests on PMDA‐ODA (using Kapton® film) in the same manner as described above for the polysulfones.…”

Section: Hydrated Polysulfonesmentioning

confidence: 99%

A molecular dynamics simulation study of three polysulfones in dry and hydrated states

Marque¹,

Verdú²,

Prunier³

et al. 2010

J Polym Sci B Polym Phys

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Molecular dynamics (MD) simulations of three polysulfones (poly(ether sulfone) PESU, poly(phenylene sulfone) PPSU and polysulfone PSU) in dry and hydrated states were undertaken in order to study the specific interactions between water and glassy polymer matrices of the same structural family. Dry polysulfone models were generated using a hybrid pivot Monte Carlo‐MD single‐chain sampling technique and the resulting relaxed densities were found to be in close agreement with experimental data. Hydrated systems are found to reproduce quite well volumetric changes experimentally observed. The concentrations of sulfonic groups can explain qualitatively their different water solubilities. Water is preferentially hydrogen‐bonded to two sites which either link two polymer sites, or one polymer site and another water, or two other waters. A detailed analysis of these water bridges that are formed is presented. Only a small quantity of potential bridging sites are occupied for water contents near the experimental saturation. The free fractional volumes, the probe accessible volumes, the swelling of the polymers, the water‐polymer interactions and the hydrogen bond lifetimes, are also presented for these polysulfones. Water‐water interactions and water clusters are found to be more important in the more hydrophilic PESU in comparison to the less hydrophilic PSU. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010

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Section: Hydrated Polysulfonesmentioning

confidence: 99%

A molecular dynamics simulation study of three polysulfones in dry and hydrated states

Marque¹,

Verdú²,

Prunier³

et al. 2010

J Polym Sci B Polym Phys

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“…Experimental measurements of the limiting weight percentage of water uptake by amorphous Kapton in contact with water vapor at its saturation pressure in the temperature range from 25 to 80 °C vary between ∼2% and ∼6%. 3,16,[23][24][25][26][28][29][30]124,[150][151][152][153][154][155] The scatter in experimental data is thought to be related to the film preparation history, the measurement technique, and in some cases the thickness of the films. 16,24,26,150 For example, Ree et al 26 It should be recalled here that, in a periodic model system, we are not limited to the amount of water that can be added to the polymer system, although phase separation is expected at very high water contents.…”

Section: Hydrated Kaptonmentioning

confidence: 99%

“…This is corroborated by dilatometry measurements, which find a maximum of 0.7% volume swelling close to the saturation pressure at room temperature. 160 Furthermore, in the dielectric water sorption analysis of Giacomelli Penon et al, 155 the change in sample thickness is deemed as being negligible in comparison with the increase in dielectric permittivity caused by the penetrating water. Most of the experimental data thus suggest that the swelling (up to saturation) remains very limited.…”

Section: Volumetric and Energetic Propertiesmentioning

confidence: 99%

“…Experimental measurements of the limiting weight percentage of water uptake by amorphous Kapton in contact with water vapor at its saturation pressure in the temperature range from 25 to 80 °C vary between ∼2% and ∼6%. ,,– ,– ,,– The scatter in experimental data is thought to be related to the film preparation history, the measurement technique, and in some cases the thickness of the films. ,,, For example, Ree et al report a value of 3.4 wt % at 25 °C obtained by microbalance measurements. Given the experimental uncertainties, it was decided here to study a broader range of weight percentages: 0%, ∼1.4% (89 H 2 O), ∼2.4% (152 H 2 O), ∼3.4% (216 H 2 O), ∼4.4% (279 H 2 O), ∼5.4% (343 H 2 O), ∼6.4% (406 H 2 O), ∼8% (508 H 2 O), and ∼10% (635 H 2 O); figures in parentheses are the corresponding actual number of water molecules inserted into the dry polymer systems of 11 712 atoms.…”

Section: Hydrated Kaptonmentioning

confidence: 99%

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Molecular Dynamics Simulation Study of Water in Amorphous Kapton

et al. 2008

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Molecular dynamics (MD) simulations of more than 40 model systems of dry and hydrated poly(pyromellitimide-1,4-diphenyl ether) (PMDA-ODA) polyimide, also known as Kapton, were undertaken in order to study the specific interactions between water and a glassy polymer matrix. Dry amorphous Kapton models were generated using a hybrid pivot Monte Carlo-MD single-chain sampling technique and were found to reproduce many features found experimentally. Water was subsequently introduced into the polyimide systems with weight percentages ranging from 1.4 to 10 wt % at 373 K. At the lower concentrations, water is found to occupy the pre-existing void space in the polymer matrix. On the other hand, there are significant changes in the volumetric, energetic, and conformational properties of the chains for water contents above ∼3%. The static and dynamic properties of the hydrogen bonds have been analyzed. In all cases under study, water is preferentially hydrogen-bonded to two sites, thus forming bridges. These water bridges, whose occurrence depends on the weight percentage of the penetrant, can link either two polymer sites, one polymer site and another water, or two other waters. Water clusters have been analyzed and found to be in agreement with findings from NMR, dielectric, and infrared attenuated total reflection (ATR) measurements. Their geometries are more chainlike and at high water contents approach a cocontinuous network. Such a characterization at the molecular level calls into question the commonly used interpretation of solubility curves based on the Zimm−Lundberg theory.

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“…On the other hand, the coating capacitance is associated with water absorption in the coating so that it can be used as a very important parameter for assessing the behavior of a coating over time. Therefore, capacitance measurements allow a better understanding of the permeability of an organic coating 23,24 .…”

Section: Resultsmentioning

confidence: 99%

Study of the Efficiency of Polypyrrole/ZnO Nanocomposites as Additives in Anticorrosion Coatings

et al. 2015

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We synthesized (ZnO nanoparticles)/polypyrrole (ZnO_NPs/PPy) hybrid nanocomposites and used them as additives in an epoxy paint to protect SAE 1020 carbon steel from corrosion. The nanocomposites were obtained by chemical polymerization of pyrrole in aqueous solution and sodium dodecyl sulfate solution containing dispersed ZnO nanoparticles. We characterized the nanoparticles by infrared absorption spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A large disparity in the distribution of ZnO particle sizes became evident from the TEM images, which also show the formation of hybrid nanocomposites consisting of polypyrrole coated ZnO nanoparticles. Electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) tests, which were performed on SAE 1020 carbon steel plates coated with epoxy and ZnO_NPs/PPy, have shown that epoxy paints have their efficiency as anticorrosive coatings significantly improved when ZnO_NPs/PPy hybrid nanocomposites are added to them.

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Dielectric water sorption analysis

Cited by 14 publications

References 14 publications

A molecular dynamics simulation study of three polysulfones in dry and hydrated states

A molecular dynamics simulation study of three polysulfones in dry and hydrated states

Molecular Dynamics Simulation Study of Water in Amorphous Kapton

Study of the Efficiency of Polypyrrole/ZnO Nanocomposites as Additives in Anticorrosion Coatings

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