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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
chemistry
Structural defects and positronium formation in 40 keV B
+
-implanted polymethylmethacrylate
Journal of Physical Chemistry B, Volume 118, No. 15, Year 2014
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Description
Slow positron beam and optical absorption measurements are carried out to study structural defects and positronium formation in 40 keV B +-implanted polymethylmethacrylate (B:PMMA) with ion doses from 6.25 × 1014 to 5.0 × 1016 ions/cm2. Detailed depth-selective information on defects in implanted samples was obtained by measuring of Doppler broadening of positron annihilation γ rays as a function of incident positron energy and these experimental results were compared with SRIM (stopping and range of ions in matter) simulation results. Two general processes, appearance of free radicals at lower ion doses (<1016 ions/cm2) and carbonization at higher ion doses (>1016 ions/cm2), are considered from the Doppler S-E and W-E dependences in the framework of the concept of defects formation during radiation damage of polymer structure. Probabilities of ortho-positronium (o-Ps) formation are analyzed using S-W plot and slow positron annihilation lifetime measurements. Dose dependence of o-Ps lifetime τ3 and intensity I3 at the incident positron energy of 2.15 keV correlates well with the dose dependence of S-parameter and seems to account for the existence of the expected two processes, i.e., scission of polymer chains and appearance of free radicals preceding the aggregation of the clusters resulting in the formation of network of conjugated bonds at lower ion doses and carbonization at higher ion doses. The increase of optical absorption observed with increasing ion implantation dose also suggests a formation of carbonaceous phase in the ion-irradiated PMMA. © 2014 American Chemical Society.
Authors & Co-Authors
Kavetskyy, Taras S.
Ukraine, Drogobich
Drohobych Ivan Franko State Pedagogical University
Tsmots, Volodymyr
Ukraine, Drogobich
Drohobych Ivan Franko State Pedagogical University
Kinomura, Atsushi
Japan, Tsukuba
National Institute of Advanced Industrial Science and Technology
Kobayashi, Yoshinori
Japan, Tsukuba
National Institute of Advanced Industrial Science and Technology
Suzuki, Ryouichi
Japan, Tsukuba
National Institute of Advanced Industrial Science and Technology
Mohamed, Hamdy F.M.
Egypt, Minya
Faculty of Science
Šauša, Ondrej
Slovakia, Bratislava
Slovak Academy of Sciences
Nuzhdin, Vladimir
Russian Federation, Kazan
E. K. Zavoisky Physical-technical Institute, Kazan Scientific Center, Russian Academy of Sciences
Valeev, Valery
Russian Federation, Kazan
E. K. Zavoisky Physical-technical Institute, Kazan Scientific Center, Russian Academy of Sciences
Stepanov, Andrey L.
Russian Federation, Kazan
E. K. Zavoisky Physical-technical Institute, Kazan Scientific Center, Russian Academy of Sciences
Statistics
Citations: 19
Authors: 10
Affiliations: 5
Identifiers
Doi:
10.1021/jp410763t
ISSN:
15206106
e-ISSN:
15205207
Research Areas
Cancer