Simulation of transient electrochemical impedance spectroscopy due to water uptake or oxide growth

Hinderliter, Brian; Croll, Stuart

doi:10.1016/j.electacta.2009.03.084

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…For comparison, diffusion through the best performing film (LFPc) was larger than that of the industry-standard solvent-borne acrylic coating by only a factor of 1.8. Calculations have demonstrated that ion movement is restricted when pores are narrowed to less than twice the diameter of the diffusing species. ,, For water, having a diameter of ∼0.3 nm, the size when movement becomes restricted is approximately 0.6 nm; therefore, the data suggest that any pores that exist in the LAPc and LFPc films are approximately 0.6 nm or smaller.…”

Section: Resultsmentioning

confidence: 94%

Minimizing Corrosion of Outdoor Metalworks Using Dispersed Chemically Stabilized Nanoclays in Polyvinylidene Fluoride Latex Coatings

2016

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Nanoclays are small enough to appear optically transparent, yet they have large surface-to-volume and high aspect ratios that can significantly inhibit water diffusion when incorporated into protective coatings. Clear coatings, which minimally affect the aesthetics of metalworks, are commonly applied to outdoor metalworks, such as sculptures, to prevent and slow corrosion. In recent years, waterborne clear coatings, rather than solvent-based clear coatings, are increasingly used in many applications to reduce the quantity of volatile organic components in the formulation, yet the performance of dry films produced from waterborne colloidal suspensions is generally poorer. In this work, we aim to improve the barrier properties of a highly weatherable waterborne acrylic/polyvinylidene fluoride emulsion by adding a synthetic nanoclay, Laponite, into the formulation. To improve clay–polymer compatibility, the clay was covalently modified using an acetoxy or perfluoroalkyl silane monomer that is reactive with the hydroxyl groups at the edges of the Laponite platelets. Cation exchange on the clay faces using phosphorylcholine was conducted to increase the stability in water and characterized by zeta potential. Resulting changes in barrier properties of the polymer nanocomposite films were characterized by gravimetry, colorimetry, and electrochemical impedance spectroscopy. Surface ablation after accelerated artificial weathering was monitored by attenuated total internal reflectance Fourier transform infrared microspectroscopy and Raman microspectroscopy, thin film X-ray diffraction (TF-XRD) and gloss and thickness measurements. The composite films showed many improved properties: reduced water sensitivity and ultraviolet-induced polymer degradation, which increased the barrier properties and reduced the diffusion constants over both short- and long-term weathering studies compared with films without nanoclays. The diffusion constant measured for the highest performing composite film showed that the performance gap between relevant water- and solvent-borne coatings used to protect outdoor metals was narrowed by half.

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Section: Resultsmentioning

confidence: 94%

Minimizing Corrosion of Outdoor Metalworks Using Dispersed Chemically Stabilized Nanoclays in Polyvinylidene Fluoride Latex Coatings

2016

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“…This is a small impact due to the short duration, 35 minutes, and small water concentration. The time to reach a particular frequency can be approximated using [5]: Where k 1 and k 2 are constants for the and equal to 100 and -1 respectively for the 50 ppd measurement employing a Gamry Reference 600.…”

Section: Resultsmentioning

confidence: 99%

“…Applying the Brasher-Kingsbury (logarithmic effective media) approximation for the change in capacitance as a function of concentration along with the power law change for the concentration [5]. Again solving for the capacitance as a function of time for a power law change in concentration generates equation:…”

Section: Resultsmentioning

confidence: 99%

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Response of Electrochemical Impedance Spectroscopy to Evolving Coating Systems

Hinderliter

2012

ECS Trans.

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Electrochemical Impedance Spectroscopy (EIS) is often used to characterize the quality of barrier coating systems with the entire spectrum from 100 kHz to 10mHz taking an hour or more to complete, during which time the coating is often changing if for no other reason than the diffusion of the electrolyte solution into the coating. When the saturated water volume fraction of the coating, the diffusion rate and the electrical response are all low, the EIS response is stable and Kramers-Kronig consistency checks are met. Higher rates of diffusion, water volume fraction, and electrical impedance response to the composite system can impact the resonance frequency and thus the relative impact on the real and imaginary components of the coating impedance. The impact on the impedance for several representative coating systems due to water uptake is compared, along with the Kramers-Kronig consistency.

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“…For example, the slope of the impedance which was taken at frequencies in the kHz range enables fast data acquisition (with a spectrum from 1 kHz–100 kHz taking fractions of a second to complete) or the first derivative approximation centered at 3 Hz may take a few seconds to acquire. While measurements that span a larger frequency range may be more likely to reveal deviations from ideally protective qualities of coatings (depending on the range), acquiring those data sets is more time consuming 26. For example, taking an EIS measurement between 0.01 and 1 MHz may take approximately 30 minutes, while an EIS measurement from 0.1 to 1 MHz may take only 5 minutes, depending on the instrument.…”

Section: Discussionmentioning

confidence: 99%

Electrochemical Identification and Categorization of the Protective Quality of Intact and Damaged Coatings

2014

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Defective polymeric coatings that are particularly relevant in the conservation of outdoor metalwork, are analyzed using electrochemical impedance spectroscopy (EIS), validated by KramersKronig transformations, and modeled using electrical equivalent circuit models (EECs). Using twenty different coated panels of five different coating types, ten mathematical methods for categorizing the protective qualities of coatings are explored as simpler and faster alternatives to circuit modeling; three methods gave a perfect correlation with the category determined by circuit modeling. Our findings highlight the need for fitting data to EECs before relying upon purely mathematical parameters for evaluating protective coating quality.

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Simulation of transient electrochemical impedance spectroscopy due to water uptake or oxide growth

Cited by 9 publications

References 11 publications

Minimizing Corrosion of Outdoor Metalworks Using Dispersed Chemically Stabilized Nanoclays in Polyvinylidene Fluoride Latex Coatings

Minimizing Corrosion of Outdoor Metalworks Using Dispersed Chemically Stabilized Nanoclays in Polyvinylidene Fluoride Latex Coatings

Response of Electrochemical Impedance Spectroscopy to Evolving Coating Systems

Electrochemical Identification and Categorization of the Protective Quality of Intact and Damaged Coatings

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