Positron decay in polymers: Molecular weight dependence in polystyrene |
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Authors: | D. H. D. West V. J. McBrierty C. F. G. Delaney |
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Affiliation: | (1) Physical Laboratory, Trinity College, University of Dublin, Dublin 2, Ireland |
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Abstract: | The decay time τl ofo-Ps by the electron pickoff process has been measured in polystyrene as a function of molecular weight. For samples below their glass transition temperature τl is essentially independent of . In the low molecular weight region, , τl increased with decreasing in line with earlier theoretical predictions. The overall behaviour reflects closely the dependence of free volume on . The effects of molecular motion on τl are examined and it is concluded that the decay time is insensitive to such motions in polystyrene below the melting point, in contrast to what is observed in polytetrafluoroethylene. |
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Keywords: | Positron annihilation Polymers |
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