title: Temperature sensitive supramolecular self assembly of per-6-PEO-β-cyclodextrin and α,ω-di-(adamantylethyl)poly(N-isopropylacrylamide) in water.
abstract: The host/guest interactions in water of a star polymer consisting of a β-cyclodextrin (β-CD) core bearing six poly(ethylene oxide) arms linked to the C6 positions of β-CD (β-CD-PEO7, Mn 5000 g mol(-1)) and α,ω-di-(adamantylethyl)poly(N-isopropylacrylamide) (Ad-PNIPAM-12K, Mn 12,000 g mol(-1)) were studied by 1D and 2D (1)H and (13)C NMR spectroscopy, isothermal calorimetry (ITC), and light scattering (LS). In cold water (T < 26 °C) supramolecular "dumbbell" assemblies, consisting of PNIPAM chains with β-CD/Ad inclusion complexes at each end, formed viaβ-CD-insertion of the terminal Ads through the β-CD secondary face. Light scattering, microcalorimetry (DSC), and DOSY NMR studies indicated that mixed aqueous solutions of β-CD-PEO7 and Ad-PNIPAM-12K undergo a reversible heat-induced phase transition at ∼32 °C, accompanied by a release of a fraction of the Ad-bound β-CD-PEO7 into bulk solution and the formation of aggregated Ad-PNIPAM-12K stabilized by a β-CD-PEO7 shell.
authors.affiliation: Université d'Evry Val d'Essonne, 91025 Evry Cedex, France.
authors.forename: V
authors.initials: V
authors.lastname: Bennevault
authors.forename: C
authors.initials: C
authors.lastname: Huin
authors.forename: P
authors.initials: P
authors.lastname: Guégan
authors.forename: K
authors.initials: K
authors.lastname: Evgeniya
authors.forename: X-P
authors.initials: XP
authors.lastname: Qiu
authors.forename: F M
authors.initials: FM
authors.lastname: Winnik
mesh_terms: D000178:Acrylamides / Q000138:chemical synthesis / Q000737:chemistry*; D000180:Acrylic Resins / Q000737:chemistry*; D000218:Adamantane / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D044367:Phase Transition; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D047392:beta-Cyclodextrins; D014867:Water; C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols; C031215:betadex; D000218:Adamantane