A capacitance study of pseudo-fickian diffusion in glassy polymer coatings

Wind, M.M.; Lenderink, H.J.W.

doi:10.1016/0300-9440(95)00601-x

Cited by 77 publications

(43 citation statements)

References 22 publications

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“…(11) is the same for diffusion driven resistivity loss of pristine material in the water swollen layer as it is for the ablation model. In this case, Type II diffusion which has a constant velocity advances linearly with time [27,[32][33][34], would be represented by the constant rate (K 1 ) term and Fickian diffusion, which advances according to the square root of time, would be represented by the second (K 2 ) term. Thus, the functional form of the effective coating thickness remains the same as a function of time, but the definition of K 1 and K 2 in Eq.…”

Section: Low Frequency Limitmentioning

confidence: 99%

Interpretation of EIS data from accelerated exposure of coated metals based on modeling of coating physical properties

Hinderliter

Croll

Tallman

et al. 2006

Electrochimica Acta

254

126

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Section: Low Frequency Limitmentioning

confidence: 99%

Interpretation of EIS data from accelerated exposure of coated metals based on modeling of coating physical properties

Hinderliter

Croll

Tallman

et al. 2006

Electrochimica Acta

254

126

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“…Many authors have used the Brasher and Kingsbury capacitive response to water along with planar diffusion approximations to estimate the diffusion of water into a coating. [2][3][4][5][6][7][8][9] EIS single frequency spectra in the capacitive region have been used to calculate the diffusion coefficient of water into a coating and saturated water concentration, 10 among other properties. Gravimetry has also been used to measure the water uptake 11,12 or loss 13 of coatings and in some cases is unsatisfactorily compared to EIS measurements of water uptake or loss.…”

Section: Introductionmentioning

confidence: 99%

Water sorption and diffusional properties of a cured epoxy resin measured using alternating ionic liquids/aqueous electrolytes in electrochemical impedance spectroscopy

et al. 2008

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The protective quality of a coating is often measured by how long it delays the arrival of water to the substrate. The transport of water in, redistribution within, and eventually through a coating to the substrate has long been investigated through electrochemical impedance spectroscopy (EIS). EIS measurements employing alternating nonaqueous (room temperature ionic liquids, RTIL) and aqueous electrolytes elucidated the behavior of water within the coating. Diffusion coefficients could be measured and the redistribution of water into percolating paths identified. The use of RTIL alternating with aqueous electrolytes allows determination of intrinsic properties (water volume fraction at saturation and relative dielectric) and kinetic properties predicted by the Brasher Kingsbury formulation. This article focuses on the sensitivity of these intrinsic and kinetic properties to test duration in an unique experimental method.

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“…Moreover, as the bulk increases, the influence of skin on the swelling decreases. This explains the time dependency of the coefficient diffusion [52,53]. For hydrogels with AAc, both n and d values increase by increasing the pH, indicating a pHdependent water transport mechanism.…”

Section: Studies Of Water Transportmentioning

confidence: 83%

Synthesis and characterization of a pH-responsive poly(ethylene glycol)-based hydrogel: acid degradation, equilibrium swelling, and absorption kinetic characteristics

et al. 2015

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We developed a pH-responsive, hydrogel based on poly(ethylene glycol) (PEG) covalently cross-linked with acrylic acid and N′,N′-dimethylacrylamide along with acidlabile groups. In the hydrogel, PEG plays a role as the key constituent. If its chains break, the polymer networks are destroyed. The pharmacological potential of these hydrogels were demonstrated by determining their water transport profile, modulus of elasticity, and cytotoxicity assay. The hydrogels showed a pseudo-Fickian behavior, a transport mechanism that occurs when the diffusion coefficient changes with the time and the swelling equilibrium is never fully reached. At pH 2, the PEG-richer hydrogels degraded and the scanning electron microscopy (SEM) images illustrated less-defined shapes than at pH 7 and 10. This morphological characteristic results of the hydrogel deconstruction owing to cleavage of ether bonds of the PEG chains unmaking its 3D polymer network. The proposed hydrogels were shown to be compatible to cells, indicating acceptable biocompatibility and an appropriate level of security for use in the biological environments. Furthermore, they showed structural changes in their polymer network in response to pH, which is an important characteristic for stimuli-triggered release of guest molecules.

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A capacitance study of pseudo-fickian diffusion in glassy polymer coatings

Cited by 77 publications

References 22 publications

Interpretation of EIS data from accelerated exposure of coated metals based on modeling of coating physical properties

Interpretation of EIS data from accelerated exposure of coated metals based on modeling of coating physical properties

Water sorption and diffusional properties of a cured epoxy resin measured using alternating ionic liquids/aqueous electrolytes in electrochemical impedance spectroscopy

Synthesis and characterization of a pH-responsive poly(ethylene glycol)-based hydrogel: acid degradation, equilibrium swelling, and absorption kinetic characteristics

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