title: Conformational changes of pyrene-labeled polyelectrolytes with pH: effect of hydrophobic modifications.
abstract: Structural changes of pyrene-labeled and unlabeled poly(maleic acid/octyl vinyl ether) (PMAOVE) and poly(maleic acid/methyl vinyl ether) (PMAMVE) with changes in pH have been investigated in this study. The changes in the photophysical properties of pyrene are interpreted to investigate uncoiling or swelling of the polymeric chains with pH. The vibrational fine structure of the pyrene fluorescence (I(3)/I(1)) and the ratio between excimer and monomer fluorescence (I(e)/I(m)) of both pyrene-labeled and unlabeled PMAMVE and PMAOVE suggest that, at pH 4, the polymers are in the coiled form and PMAOVE forms hydrophobic nanodomains. An increase in pH ionizes a number of COOH groups on both PMAMVE and PMAOVE, which leads to the stretching or swelling of the polymers.
authors.affiliation: NSF IUCR Center for Advanced Studies in Novel Surfactants, Langmuir Center for Colloid and Interfaces, Columbia University, New York, NY 10027, USA.
authors.forename: Puspendu
authors.initials: P
authors.lastname: Deo
authors.forename: Namita
authors.initials: N
authors.lastname: Deo
authors.forename: P
authors.initials: P
authors.lastname: Somasundaran
authors.forename: Steffen
authors.initials: S
authors.lastname: Jockusch
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Turro
mesh_terms: D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008298:Maleates / Q000737:chemistry*; D008968:Molecular Conformation; D011095:Polyethylenes / Q000737:chemistry*; D011721:Pyrenes / Q000737:chemistry*
chemical_list: D008298:Maleates; D011095:Polyethylenes; D011721:Pyrenes; C043105:poly(methyl vinyl ether-co-maleic anhydride)