PVP ‐stabilized arsenic sulfide A s4 S 4 nanocomposites probed with positron annihilation lifetime spectroscopy

Atomic‐deficient nanostructurization in composites based on arsenic sulfide As4S4 polymorphs, such as (1) β‐As4S4, (2) realgar α‐As4S4, and (3) mixture of realgar, pararealgar, and intermediate χ‐phase subjected to high‐energy mechanochemical milling in polyvinylpyrrolidone (PVP) solution, are studied exploring the method of positron annihilation lifetime spectroscopy. Positron lifetime spectra reconstructed from unconstrained x3‐term fitting procedure testify in a favor of mixed positron‐positronium trapping in the studied composites. Modified x3‐x2‐coupling decomposition algorithm is applied to parameterize expected annihilation channels in As4S4‐PVP nanocomposites in respect to PVP matrix. Interfacial free‐volume voids between nanoparticles composed of arsenic sulfide crystallites embedded in PVP environment are defined as most favorable positron trapping sites, loosely packed in respect to variety of crystallographic polymorphs used for milling. POLYM. ENG. SCI., 57:502–505, 2017.