Positron annihilation lifetime (PAL) in poly[1-(trimethyl-silyl)propine] (PTMSP): Free volume determination and time dependence of permeability

Positronium Formation in Organic Liquids

“…There is practically no information on o-Ps lifetimes and intensities as a function of oxygen content at different physical conditions (temperature, presence of magnetic and electric fields). Some more quantitative studies on o-Ps paramagnetic quenching by O 2 were undertaken in [12,13]. In the first paper [12] the influence of magnetic field on the ortho−para conversion induced by O 2 in some plastic membranes is investigated, while more recent work deals with the role of oxygen solubility in different organic liquids.…”

“…Some more quantitative studies on o-Ps paramagnetic quenching by O 2 were undertaken in [12,13]. In the first paper [12] the influence of magnetic field on the ortho−para conversion induced by O 2 in some plastic membranes is investigated, while more recent work deals with the role of oxygen solubility in different organic liquids. Excluding these works, most of experimental data on paramagnetic quenching come from relatively "old" papers (e.g.…”

Positron annihilation and free volume studies in polymer glasses

“…Such a comparison enables to check some ideas on the mechanisms of o-Ps trapping and the accuracy of the lifetime spectrums processing. [33][34][35][36][37] For the super-crosslinked polystyrene 36 (Table2), there was found a good correlation between PAL and sorption data, when longlived o-Ps components s 4 , I 4 and s 5 , I 5 were used. A good correlation was seen in the fact that, from the pores detected by sorption method, o-Ps was always trapped by those having smaller size but higher concentration.…”

Discrete and Continuous Analysis of Positron Lifetime Spectra: a Comparison

“…Details on the membrane preparation can be found elsewhere [9]. The positron source (0.3 MBq of 22 Na) was embedded into two identical Kapton foils; the sourcesample assembly was inserted into a liquid nitrogen cryostat and positron spectra were obtained under vacuum at six temperatures: 180, 240, 300, 360, 420 and 480 ± 0.5 K, through a conventional fast-fast coincidence apparatus, having a resolution of about 250 ps.…”