Positron annihilation study of the free volume changes in bifocal contact lenses

Filipecki, J.; Korzekwa, Piotr; Filipecka, Katarzyna; Hyla, M.; Korzekwa, Dominika; Golis, Edmund; Korzekwa, Witold

doi:10.30970/cma4.0137

Cited by 2 publications

(2 citation statements)

References 13 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We observed a decrease of lifetime from 2.4 ns to 1.4 ns which in terms of diameter of the free volume is about 0.7 nm to 0.5 nm; 0.7 nm is the equivalent length between sulfonic group and backbone …”

Section: Resultsmentioning

confidence: 77%

Positron annihilation spectroscopy studies of proton exchange membranes used in fuel cells

Constantin

Barna

Mereuta

2015

Polymers for Advanced Techs

View full text Add to dashboard Cite

In the recent years, fuel cells became more than a promise, getting closer to a technological reality. Proton exchange membrane (PEM) used as electrolyte is a valuable solution, and Nafion W seems to be the best competitor. This paper reports a positron annihilation spectroscopy study of Nafion W behavior employed as a proton exchange membrane in a working fuel cell. A continuous survey of the fuel cell behavior using positron annihilation lifetime spectroscopy and coincidence Doppler broadening spectroscopy was conducted over a 50-day period, and the results of these measurements are presented and discussed.

show abstract

Section: Resultsmentioning

confidence: 77%

Positron annihilation spectroscopy studies of proton exchange membranes used in fuel cells

Constantin

Barna

Mereuta

2015

Polymers for Advanced Techs

View full text Add to dashboard Cite

show abstract

“…On the basis of the free‐volume theory proposed by Tao and Eldrup, o ‐Ps particles reside in a spherical potential well and possess an infinite potential barrier of radius R 0 . The thickness of the electron layer formed on the wall of the hole is presented as Δ R .…”

Section: Resultsmentioning

confidence: 99%

Influence of a rigid polystyrene block on the free volume and ionic conductivity of a gel polymer electrolyte based on poly(methyl methacrylate)‐block‐polystyrene

Guan

Chen

et al. 2016

J of Applied Polymer Sci

View full text Add to dashboard Cite

Diblock copolymers poly(methyl methacrylate)-block-polystyrene with three different molar ratios [poly(methyl methacrylate)/polystyrene (PS) 5 1:1, 1:1.5, and 1:1.8] were synthesized by atom transfer radical polymerization and used as a polymer matrix for gel polymer electrolytes (GPEs). The positron annihilation lifetime spectroscopy was applied to determine the free-volume behaviors of different GPEs, respectively. We illustrated that a proper PS ratio may led to the formation of a high fraction of free volume, and the influence of the PS ratio on the free-volume fraction was caused by the different morphologies of the GPEs because of the different packing densities of the PS rigid block. The ionic conductivity was correlated with the free volume in the GPE through the study of the ionic conductivity dependence on the temperature; this followed the Vogel-Tamman-Fulcher equation. Moreover, an ionic conductive model was proposed, in which variations of the free-volume behavior provide different ionic-conducting abilities. Thermogravimetric analysis indicated that GPEs based on different block copolymers exhibited high liquid-electrolyte preservation properties.

show abstract

Positron annihilation study of the free volume changes in bifocal contact lenses

Cited by 2 publications

References 13 publications

Positron annihilation spectroscopy studies of proton exchange membranes used in fuel cells

Positron annihilation spectroscopy studies of proton exchange membranes used in fuel cells

Influence of a rigid polystyrene block on the free volume and ionic conductivity of a gel polymer electrolyte based on poly(methyl methacrylate)‐block‐polystyrene

Contact Info

Product

Resources

About