The use of positron annihilation lifetime technique to study the effect of doping metal salts on polyhydroxamic acid polymers

Abstract

Polyhydroxamic acid (PHA) from polymethacrylamide (PMAA) was prepared. Chromium chloride (CrCl 3 ) and ferric chloride (FeCl 3 ) salts were added to the polymer in order to increase its electrical conductivity, i.e., the dopants help produce semiconducting properties. The positron annihilation lifetime technique spectroscopy (PALS) was used to study the changes in the free volume as a function of FeCl 3 and CrCl 3 concentrations. ortho-Positronium lifetime components were used to estimate the free volume parameters. It was found that the hole size and the total free volume fraction decreased with FeCl 3 concentration. On the other hand, the hole size increased slightly with CrCl 3 concentration and then decreased, while the total free volume fraction increased continuously. The free volume distributions were determined from ortho-positronium distributions. The electric conductivity as a function of FeCl 3 and CrCl 3 concentrations showed fluctuation behavior and showed a continuous increase with the increase in temperature. The correlation between positron annihilation parameters and electric conductivity were discussed.

Comparison between the effects of alcohols and diols on polymethyl‐methacrylate and polyacrylamide with positron annihilation lifetime and electric conductivity measurements

“…8 Specimens of 1 cm diameter and 1 mm thickness were tightly adjusted between the plates of two copper electrodes of an electric cell. The electric circuit used was composed of a regulated DC power supply, a high-impedance electrometer (Keithley electrometer of the type 610c), and the cell.…”

Microstructure and positron behavior in FeCl3 doped PVA/PVP blend

“…Besides the inhibition explained above, the quenching of Ps due to FeCl 3 or Fe 3+ ions could also be observed on account of spin conversion process. FeCl 3 being a metal salt possess paramagnetic properties and the Fe 3+ ion is a high spin ion with half filled d-sub shell and is expected to affect the Ps formation to a greater extent [7]. However, it is known that the Fe +3 interaction with Ps promotes oxidation reaction which leads to the quenching of Ps in the polymer matrix.…”

The use of positron annihilation to study polyacrylamide and polymethylmethacrylate—Alcohols and diols mixture

“…The specific electrical conductivity of PAA and PMMA-alcohols and diols polymer mixture was measured by the method mentioned before [10]. Specimens of 1 cm diameter and 1 mm thickness were tightly adjusted between the plates of two copper electrodes of an electric cell.…”