Fluorescence quenching by nitromethane of pyrene-labeled poly(N-isopro
pylacrylamides) (PNIPAMs) which contain alkyl chains was employed to i
nvestigate the accessibility of the quencher to the pyrene moieties. T
he quenching efficiency for monomeric pyrene or excimers was decreased
in PNIPAMs when compared to the quenching efficiency of pyrene fluore
scence in the aqueous phase, showing that pyrene is always located wit
hin the polymeric micelles. The contribution of static quenching was e
valuated by comparing the quenching efficiency determined from steady-
state measurements with that obtained from time-resolved data. Static
quenching was present for all PNIPAMs studied. The decrease of the que
nching efficiency was related to the polymeric micelle structure. The
highest degree of protection was observed for the excimer emission of
the polymer containing randomly-substituted alkyl chains and with the
pyrene bound to the same polymeric unit as the alkyl chain.