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Dynamics of siloxane chains bearing phenyl chromophores
Author(s) -
Horta Arturo,
Maçanita António L,
Freire Juan J,
Piérola Inés F
Publication year - 1999
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(199908)48:8<665::aid-pi208>3.0.co;2-#
Subject(s) - siloxane , chromophore , bearing (navigation) , materials science , polymer science , polymer chemistry , dynamics (music) , molecular dynamics , polymer , computational chemistry , chemistry , composite material , organic chemistry , computer science , physics , artificial intelligence , acoustics
Molecular dynamics simulations are used to model the conformational motions associated with transitions between rotational states which may be responsible for the coupling between chromophores (excimer forming states) in the chains of poly(methylphenylsiloxane). Analysis of the trajectories show that the rotations around backbone bonds occur much faster than the coupling–uncoupling between the lateral chromophores. Although fast, the rotations around backbone bonds are strongly coordinated, each pair of SiOSi bonds rotating in a concerted fashion, such that the lateral phenyl groups (attached to the Si atoms) remain coupled over long times (many backbone rotations). The quantitative assessment of these results is established by calculating the correlation times for the backbone rotational angles (SiO), for the distance separating chromophores (Ph···Ph), and for the lateral SiPh bonds. The relevance for the kinetics of excimer emission is discussed. © 1999 Society of Chemical Industry