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Interactions between Chromophore‐Labelled Ammonium Surfactants and Hydrophobically Modified Polyelectrolytes
Author(s) -
Nieuwkerk Armanda C.,
van Kan Ellen J. M.,
Koudijs Arie,
Marcelis Antonius T. M.,
Sudhölter Ernst J. R.
Publication year - 1999
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199901)1999:1<305::aid-ejoc305>3.0.co;2-m
Subject(s) - chemistry , polyelectrolyte , chromophore , polymer chemistry , azobenzene , micelle , alkyl , vinyl ether , pulmonary surfactant , maleic acid , substituent , cooperativity , ether , aqueous solution , photochemistry , copolymer , organic chemistry , polymer , biochemistry
The interaction of poly(maleic acid‐ co ‐alkyl vinyl ether)s and poly(sulfonylethyl maleic acid monoamide‐ co ‐alkyl vinyl ether)s with and without (cyanobiphenylyl)oxy chromophores with N ‐[ω‐(substituted azobenzoxy)alkyl]‐ N , N ‐dimethyl‐ N ‐hydroxyethylammonium bromide surfactants has been studied by UV spectroscopy. The azobenzene unit is functionalized at the 4′‐position with a cyano or fluoro substituent and is connected to the surfactant headgroup via a decyl or dodecyl spacer. Upon addition of surfactants to poly(maleic acid‐ co ‐butyl vinyl ether) the absorption maxima (λ max ) of the azobenzene chromophores immediately show their maximum blue shift. This indicates cooperative binding of surfactant to this polymer, and the formation of micelle‐like aggregates surrounded by polyelectrolyte is assumed. Upon addition of the surfactants to the other polyelectrolytes λ max values of the azobenzoxy chromophores gradually shift to lower values indicating a lower cooperativity of surfactant binding. This is attributed to the formation of microdomains by the polyelectrolytes themselves. For these systems the formation of mixed micelles is assumed. The compactness of the microdomains of the maleic acid copolymers is influenced by the pH and binding with surfactants is also influenced by pH. The sulfonylethyl maleic acid monoamide copolymers show no pH dependence in binding above neutral pH. For these polyelectrolytes the cooperativity also becomes less with a longer spacer between backbone and chromophore. Upon elongation of the surfactant spacer or changing the end group from a cyano to the more hydrophobic fluoro substituent a lower λ max is observed for the chromophores upon initial binding to the polyelectrolytes indicating more cooperative binding. When surfactants and polyelectrolytes are both labelled with chromophores, binding proceeds noncooperatively and the formation of mixed micelles is assumed.