Thickness dependence of the porosity of PPy/DDS films

Hallik, Allan; Roosalu, Kaspar; Mändar, Hugo; Joosu, Lauri; Marandi, Margus; Tamm, Jüri

doi:10.1016/j.eurpolymj.2015.07.002

Cited by 6 publications

(4 citation statements)

References 33 publications

(56 reference statements)

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“…RSAXS revealed the ionic domain spacing ( d -spacing = 2π/ q p,max , where q p corresponding to the ionic domain spans between 1.5 and 3.5 nm –1 ). In addition, a subsequent least-squares fit of the ionic domain peaks using in Nanosolver , (a built-in software of Rigaku Smartlab Diffractometer) gave the average size of ionic domains ( d id ) in all ionomer films at dry and humid conditions, where the experimentally calculated d -spacing for a film was used as an input parameter. By analyzing the nanoscale morphology (of the dry ionomer films using bright-field transmission electron microscopy), water uptake (λ w , quartz crystal microbalance), pH (fluorescence), proton concentration (fluorescence), and ionic domain size (fluorescence, RSAXS) within ionomer films, we rationalized the observed extent of proton conduction ( I d / I p ) in sub-μm thick ionomer films, and evaluated the most important parameters impacting the proton conduction under nanoconfinement.…”

Section: Introductionmentioning

confidence: 99%

Fluorocarbon-Based Ionomers with Single Acid and Multiacid Side Chains at Nanothin Interfaces

Farzin

Yandrasits²,

Dishari

2019

J. Phys. Chem. C

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Unraveling ion conduction limitations in nanothin ionomer films is crucial for designing efficient ionomer−catalyst interfaces and improving redox efficiency in electrochemical devices. This work took a multifaceted approach to understand local proton conduction environments in sub-μm thick films of three fluorocarbon-based ionomers, Nafion, 3M PFSA and 3M PFIA with IEC ∼ 0.91, 1.21, and 1.61 mequiv/g, respectively. After incorporating fluorescent photoacid probe pyranine (HPTS) into films, the extent of proton conduction (I d /I p ), local proton concentration, pH, and ionic domain size (d id ) were predicted by monitoring the ratio of fluorescence intensity of deprotonated (I d ) to that of the protonated (I p ) state of HPTS. I d /I p decreased with film thickness and followed the trend: 3M PFIA > 3M PFSA > Nafion. A higher water uptake did not necessarily lead to higher I d /I p indicating that other factors than water uptake control proton conduction under confinement. Size of the ionic domains (d id ), measured independently using in-plane reflection small-angle X-ray scattering and fluorescence spectroscopy, followed the same trend as I d /I p . As the RH and film thickness decreased, d id became smaller. The close match of d id obtained from both techniques supported the reliability of information confered by fluorescence spectroscopy about key controlling parameters of the local proton conduction environment. The highest I d /I p of 3M PFIA films was attributed to its flexible, multiacidic side chain that helped to form larger ionic domains with better phase segregation. Conversely, smaller, extremely acidic and poorly phase segregated ionic domains with highly confined water molecules led to lower I d /I p in Nafion films, despite high water uptake.

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Section: Introductionmentioning

confidence: 99%

Fluorocarbon-Based Ionomers with Single Acid and Multiacid Side Chains at Nanothin Interfaces

Farzin

Yandrasits²,

Dishari

2019

J. Phys. Chem. C

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“…53 This fact is related to the polymer chain opening and, consequently, the increase in the pores present in the films. In parallel, the literature 73 shows a dependence between thickness and porosity of polypyrrole and dodecyl sulfate films. Thus, the film thicknesses must be considered, as they indirectly influence the permeability coefficient.…”

Section: Drug Permeation Proceduresmentioning

confidence: 88%

Chitosan and Agaricus brasiliensis Polysaccharides Films: A Preliminary Study

Gonzaga

Campelo

Saraiva

et al. 2020

J. Braz. Chem. Soc.

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The known biotechnological properties of chitosan and the recent biological activities attributed to polysaccharides from Agaricus brasiliensis have been of interest to obtain films constituted by these two polymers. The glucans obtained from the mushroom inhibited about 96.5% of the ferrous ion, besides not promoting a significant increase of lactate dehydrogenase enzyme (LDH), which indicates that the polysaccharide is able to inhibit the production of radical species and also presents low cytotoxicity to the biological systems. The results of spectroscopy analyses in the infrared region (FTIR) and X-ray diffraction suggest an existing electrostatic interaction between the substances. A reduction in the films' swelling capacity was observed with an increase in the polysaccharide content in the composition. In addition, scanning electron microscopy (SEM) revealed greater surface density of the films. In convening the biological properties of the substances, it is expected that this study raises interest in evaluating the films and their capacity for healing wounds and burns.

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“…where is the porosity. Taking the porosity of NPG of ∼ 0.7 and PPy film density of ρ PPy = 1.5 g/cm 3 [65,66], τ was estimated to be 1.08, 1.10, and 1.17 for NPG, NPG/PPy(10 nm), and NPG/PPy(30 nm), respectively. As has been reported, the change in Poisson's ratio of nanoporous gold with ligament size of 120∼180 nm, which embraces the ligament size in the present work, was smaller than 0.025 when the NPG was compressed up to 20% [67].…”

Section: Discussionmentioning

confidence: 99%

Electrochemical Behavior of Nanoporous Gold/Polypyrrole Supercapacitor under Deformation

Jia

et al. 2022

Nanomaterials

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Due to the high demand of wearable electronics, flexible supercapacitors have been extensively developed in recent years. Yet, the effect of deformation in the interior electrode material suffered in practical applications on the performance received less attention. Here, we study the electrochemical behavior of macroscopic nanoporous gold/polypyrrole (NPG/PPy) in situ under compression deformation. Dealloying-driven NPG, a network constructed by bi-continuous nano-scaled ligaments and pores, can serve as a compression-tolerant substrate for PPy supercapacitor material. The electrochemical capacitance of NPG/PPy subjected to compression deformation is revealed to decrease at the scan rates and discharge current densities applied in this work. At the same time, the charge transfer resistance of NPG/PPy is found to increase. This electrochemical behavior is due to the locally reduced mass transport of electrolyte caused by the formation of new connections between the neighboring ligaments under the application of compression loads. The fundamental understanding of the effect of deformation on the performance of energy storage materials revealed in this study paves the way for their practical application in wearable devices.

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Thickness dependence of the porosity of PPy/DDS films

Cited by 6 publications

References 33 publications

Fluorocarbon-Based Ionomers with Single Acid and Multiacid Side Chains at Nanothin Interfaces

Fluorocarbon-Based Ionomers with Single Acid and Multiacid Side Chains at Nanothin Interfaces

Chitosan and Agaricus brasiliensis Polysaccharides Films: A Preliminary Study

Electrochemical Behavior of Nanoporous Gold/Polypyrrole Supercapacitor under Deformation

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