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Characterization of blends of naphthalene‐containing polymers with poly(alkyl methacrylates) by combined steady‐state fluorescence spectroscopy and fluorescence decay measurements
Author(s) -
Holden David A.,
Strauss John
Publication year - 1988
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760282106
Subject(s) - excimer , chromophore , fluorescence , monomer , materials science , methacrylate , emission spectrum , alkyl , methyl methacrylate , polymer , naphthalene , fluorescence spectroscopy , analytical chemistry (journal) , photochemistry , steady state (chemistry) , polymer chemistry , chemistry , spectral line , organic chemistry , optics , composite material , physics , astronomy
The extent of mixing in two‐component solution‐cast films of poly(2‐vinyl naphthalene) (P2VN) and poly(2‐iso‐propenyl naphthalene) (P2IPN) with poly(methyl methacrylate) and poly(n‐butyl methacrylate) was studied by steady‐state and time‐resolved fluorescence spectroscopy. The steady‐state fluorescence spectrum of 1% P2IPN in the two poly(alkyl methacrylates) evolves from 100% monomer emission (λ max = 340 nm) to >70% excimer emission (λ max = 390 nm) as its molecular weight increases from 1900 to 278000. Despite such clear‐cut changes in the steady‐state spectra on phase separation, the fluorescence decays were nonexponential for all mixed films. Triple‐exponential decay functions were necessary to describe excimer decays at 430 nm and monomer decays at 340 nm. Moreover, the fluorescence decays varied slightly across the excimer emission band, and changed significantly when the polymer films were annealed. Studies on blends containing from 1 to 100% of P2VN and P2IPN established that this multicomppnent fluorescence decay behavior is intrinsicto the naphthalene‐containing polymer phase, it is proposed that excimers formed between chromophores in meso and racemic dyads have different mean decay times and that imperfectly aligned chromophore pairs lead to an additional short‐lived excimer decay component.