Temperature dependence of positron-annihilation lifetime, free volume, conductivity, ionic mobility, and number of charge carriers in a polymer electrolyte polyethylene oxide complexed withNH4ClO4

1996 ◽  
Vol 54 (10) ◽  
pp. 7143-7150 ◽  
Author(s):  
B. Haldar ◽  
R. M. Singru ◽  
K. K. Maurya ◽  
S. Chandra
Keyword(s):  
Temperature Dependence ◽  
Polymer Electrolyte ◽  
Positron Annihilation ◽  
Free Volume ◽  
Polyethylene Oxide ◽  
Ionic Mobility ◽  
Charge Carriers ◽  
Positron Annihilation Lifetime ◽  
Volume Conductivity

Positron Annihilation Lifetime Study of Graft-Type Fluorinated Polymer Electrolyte Membranes

2008 ◽  
Vol 607 ◽  
pp. 70-72 ◽  
Author(s):  
Shin-ichi Sawada ◽  
Atsuo Kawasuso ◽  
Masaki Maekawa ◽  
Akihiro Suzuki ◽  
Takayuki Terai ◽  
...  
Keyword(s):  
Polymer Electrolyte ◽  
Positron Annihilation ◽  
Free Volume ◽  
Sulfonic Acid ◽  
Graft Polymerization ◽  
Polymer Electrolyte Membranes ◽  
Positron Annihilation Lifetime ◽  
Electrolyte Membranes ◽  
Radiation Induced ◽  
Styrene Sulfonic Acid

Positron annihilation lifetime spectroscopy (PALS) measurements were performed on polymer electrolyte membranes (PEMs) synthesized by radiation-induced graft polymerization of styrene into crosslinked-polytetrafluoroethylene (cPTFE) films and subsequent sulfonation. The base cPTFE and polystyrene grafted films were also measured as references. The cPTFE based PEM was found to have free-volume holes with different radius of 0.28-0.30 nm and 0.44-0.45 nm. The larger holes may be located in PTFE amorphous regions, while the smaller ones are considered to exist in both PTFE crystallites and poly(styrene sulfonic acid) grafts containing no water.

Preliminary Positron Lifetime Results on Free Volumes in Cyclodextrins

2010 ◽  
Vol 666 ◽  
pp. 99-102 ◽  
Author(s):  
Maria Fatima Ferreira Marques ◽  
A.M.G. Moreira Da Silva ◽  
P.M. Gordo ◽  
Z. Kajcsos
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Positron Lifetime ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Positron Source ◽  
Lifetime Component ◽  
Positron Annihilation Lifetime ◽  
Long Lifetime

Positron annihilation lifetime spectroscopy was used to study the free-volume parameters in various pure -, - and -cyclodextrins samples and, in the case of β-cyclodextrin, with inclusion of S-carvone and thymoquinone. The results clearly indicate the presence of long lifetime components related to Ps-formation. The data show that the addition of S-carvone to β-cyclodextrin results in a decrease of o-Ps lifetime that we ascribe to a reduction of free volume holes from 81.8 to 63.7 Å3. The long lifetime component disappears when thymoquinone is added to -cyclodextrin, indicating this substance acts as an o-Ps quencher. For all samples studied, a decrease in the long lifetime component values was observed with increasing source in situ time, a result that might be attributed to the irradiation of the sample by the 22Na positron source.

Ceramide increases free volume voids in DPPC membranes

RSC Advances ◽  
2015 ◽  
Vol 5 (55) ◽  
pp. 44282-44290 ◽  
Author(s):  
E. Axpe ◽  
A. B. García-Arribas ◽  
J. I. Mujika ◽  
D. Mérida ◽  
A. Alonso ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Lipid Membranes ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Positron Annihilation Lifetime

We have measured by positron annihilation lifetime spectroscopy (PALS) that ceramide increases the size of the free volume holes in DPPC lipid membranes.

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