Abstract
Interactions between the moieties responsible for the conformations and hydrophobic microdomains in poly(styrene-4-sulphonate) (PSS) and its copolymers with n-butylvinylether (BVE) were studied by their emission spectra and the lifetimes of the phenyl groups and pyrene used as a photochemical probe. The emission spectra of PSS shows bands due to dimers and higher aggregates as well as the characteristic excimer band. At low concentrations, the random copolymers have spectra similar to that of the free monomer, whereas the block copolymers have spectra like that of PSS. At higher concentrations, the random copolymer also shows these excimer bands, due to interchain interactions. Results from the emission of pyrene prove that the behaviour of the copolymers with approximately 40% BVE seems to be relatively independent of having random or block configurations. Except at low concentrations (<0.05 g/dl), where the block copolymer already has a conformation with “stable” hydrophobic microdomains, both types of copolymers behave similarly. There is an initial aggregate equilibrium between individual chains and aggregates, associated with a relocation of the probes. At higher concentrations, both copolymers suffer a severe change in conformation, due to the formation of “stable” hydrophobic microdomains, resulting from interchain interactions. In both cases the lifetimes of pyrene are of the order of 240 ± 10 ns.
Published Version
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