Nanocomposites and nanomaterials

Positron trapping-reduction processes in the engineering of functionally-optimized polymer-matrix nanocomposites: 
the case of PVP-capped glassy arsenoselenides
Shpotyuk O.1,2, Ingram A.3, Shpotyuk Y.4,5, Filipecki J.1
1  Jan Dlugosz University in Czestochowa 
Armii Krajowej str., 13/15, 42-200, Czestochowa, Poland
2  Vlokh Institute of Physical Optics
Dragomanov str., 23, 79005 Lviv, Ukraine
3  Opole University of Technology
Ozimska str., 75, 45370 Opole, Poland
4  Ivan Franko National University of Lviv, 
Universytetska str., 79000, 1, Lviv, Ukraine
5 Faculty of Mathematics and Natural Sciences, University of Rzeszow
Pigonia str., 1, 35-959, Rzeszow, Poland 

Methodological possibilities of positron annihilation lifetime (PAL) spectroscopy applied to characterize nanosization processes in polymer-matrix nanocomposites are analyzed. The fundamentals of PAL spectroscopy applied to inhomogeneous nanoparticle-embedded substances are discussed. 
The algorithm to treat PAL data for such substances within three-state mixed trapping model evolving competitive channels of positron and positroniun Ps (bound electron-positron state) annihilation referred to as the x3-x2-CDA (coupling decomposition algorithm) [1,2] is given. Under high-energy wet milling, the inter-nanoparticle Ps-decaying sites in preferential PVP environment are shown to replace free-volume positron traps in dry-milled pellets with defect-specific positron lifetime corresponding to di-/tri-atomic vacancies in g-As-Se matrix.  

1.	Shpotyuk O., Filipecki J., Ingram A., Golovchak R., Vakiv M., Klym H., Balitska V., Shpotyuk M., Kozdras A. Positronics of subnanometer atomistic imperfections in solids as a high-informative structure characterization tool // Nanoscale Res Lett.-2015.-10.-P. 77-1-5.
2.	Shpotyuk O., Ingram A., Shpotyuk Ya. Free-volume characterization of nanostructurized substances by positron annihilation lifetime spectroscopy // Nucl Instr Meth Phys Res. B.-2018.-416.-P. 102-109.