SAXS signature of the lamellar ordering of ionic domains of perfluorinated sulfonic-acid ionomers by electric and magnetic field-assisted casting

J, da Silva; Carvalho, Sabrina G. M.; Silva, Rodrigo P. da; Tavares, Ana C.; Schade, U.; Puškar, Ljiljana; Fonseca, Fábio C.; Matos, Bruno R.

doi:10.1039/d0cp01864c

Cited by 13 publications

(17 citation statements)

References 59 publications

(143 reference statements)

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“…To obtain initial estimates of the layer thicknesses for simulations, SEM measurements were performed, The SEM micrograph in Figure c (and Supporting Figure S5) shows the layering of the DBR after the microcavity was freeze-cracked, which caused uneven fracture artifacts in the image. The AQ layers are distinguishable thanks to their spherical aggregates, which have been previously reported in the literature for perfluorosulfonic acid ionomer dispersions . From the SEM images, the uniformity is clear.…”

Section: Resultssupporting

confidence: 67%

“…The AQ layers are distinguishable thanks to their spherical aggregates, which have been previously reported in the literature for perfluorosulfonic acid ionomer dispersions. 33 From the SEM images, the uniformity is clear. As described in detail in Supporting Figure S6 , the average thickness of the AQ layers was estimated to be 108 ± 8 nm, and that of PVK was estimated to be 65 ± 6 nm.…”

Section: Resultsmentioning

confidence: 94%

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All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

et al. 2022

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Controlling the radiative rate of emitters with macromolecular photonic structures promises flexible devices with enhanced performances that are easy to scale up. For instance, radiative rate enhancement empowers low-threshold lasers, while rate suppression affects recombination in photovoltaic and photochemical processes. However, claims of the Purcell effect with polymer structures are controversial, as the low dielectric contrast typical of suitable polymers is commonly not enough to provide the necessary confinement. Here we show all-polymer planar microcavities with photonic band gaps tuned to the photoluminescence of a diketopyrrolopyrrole derivative, which allows a change in the fluorescence lifetime. Radiative and nonradiative rates were disentangled systematically by measuring the external quantum efficiencies and comparing the planar microcavities with a series of references designed to exclude any extrinsic effects. For the first time, this analysis shows unambiguously the dye radiative emission rate variations obtained with macromolecular dielectric mirrors. When different waveguides, chemical environments, and effective refractive index effects in the structure were accounted for, the change in the radiative lifetime was assigned to the Purcell effect. This was possible through the exploitation of photonic structures made of polyvinylcarbazole as a high-index material and the perfluorinated Aquivion as a low-index one, which produced the largest dielectric contrast ever obtained in planar polymer cavities. This characteristic induces the high confinement of the radiation electric field within the cavity layer, causing a record intensity enhancement and steering the radiative rate. Current limits and requirements to achieve the full control of radiative rates with polymer planar microcavities are also addressed.

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Section: Resultssupporting

confidence: 67%

Section: Resultsmentioning

confidence: 94%

All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

et al. 2022

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“…Protons are easily transferred in PEM if the λ value is appropriate. By substituting the known IEC value and the water uptakes at every temperature into the equation below, the value of λ was determined [ 31 , 32 ].

…”

Section: Methodsmentioning

confidence: 99%

Electric Field-Assisted Filling of Sulfonated Polymers in ePTFE Backing Material for Fuel Cell

et al. 2022

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This study fabricated a composite ePTFE-backed proton-exchange membrane by filling the pores on the ePTFE backing with sulfonated polyarylene ethers through an externally supplied electric field. The morphology changes were observed under an SEM. The results suggested that the application of an electric field had led to the effective filling of pores by polymers. In addition, the composite membrane featured good dimensional stability and swelling ratio, and its water uptake, proton conductivity and component efficiency increased with voltage. It is found in this study that the external application of an electric field resulted in the effective filling of pores in the ePTFE by sulfonated polyarylene ether polymers and, thus, an improved composite membrane performance.

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“…7 | P a g e PFSA ionomers have been available for over 50 years, and their morphology has been the subject of continuous research and debate. 105,106,107 Small and wide-angle x-ray and small angle neutron scattering, and molecular modeling are common techniques used to probe polymer morphology. Scattering measurements involve the detection of a scattered incident beam of known wavelength upon interaction with a material's electronic (X-ray) or nuclear (neutrons) structure.…”

Section: Aspects To Consider For Proton Exchange Membranesmentioning

confidence: 99%

On the evolution of sulfonated polyphenylenes as proton exchange membranes for fuel cells

2021

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SAXS signature of the lamellar ordering of ionic domains of perfluorinated sulfonic-acid ionomers by electric and magnetic field-assisted casting

Abstract: The origins of the matrix and ionomer peaks of Nafion SAXS pattern are revisited.

Cited by 13 publications

References 59 publications

All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

Electric Field-Assisted Filling of Sulfonated Polymers in ePTFE Backing Material for Fuel Cell

On the evolution of sulfonated polyphenylenes as proton exchange membranes for fuel cells

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