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hal.structure.identifierLaboratoire de Chimie des polymères organiques [LCPO]
dc.contributor.authorFENG, Xiaoshuang
hal.structure.identifierLaboratoire de Chimie des polymères organiques [LCPO]
hal.structure.identifierTeam 1 LCPO : Polymerization Catalyses & Engineering
dc.contributor.authorTATON, Daniel
hal.structure.identifierLaboratoire de Chimie des polymères organiques [LCPO]
dc.contributor.authorBORSALI, Redouane
hal.structure.identifierLab Biomol Mat Res [LBMR]
dc.contributor.authorCHAIKOF, Elliot L.
hal.structure.identifierLaboratoire de Chimie des polymères organiques [LCPO]
dc.contributor.authorGNANOU, Yves
dc.date.accessioned2020
dc.date.available2020
dc.date.issued2006
dc.identifier.issn0002-7863
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/20727
dc.description.abstractEnPoly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA), two polymers known to form pH-sensitive aggregates through noncovalent interactions, were assembled in purposely designed architecture sa dendrimer-like PEO scaffold carrying short inner PAA chains-to produce unimolecular systems that exhibit pH responsiveness. Because of the particular placement of the PAA chains within the dendrimer-like structure, intermolecular complexation between acrylic acid (AA) and ethylene oxide (EO) units-and thus macroscopic aggregation or even mesoscopic micellization-could be avoided in favor of the sole intramolecular complexation. The sensitivity of such interactions to pH was exploited to generate dendrimer-like PEOs that reversibly shrink and expand with the pH. Such PAA-carrying dendrimer-like PEOs were synthesized in two main steps. First, a fifth-generation dendrimer-like PEO was obtained by combining anionic ring-opening polymerization (AROP) of ethylene oxide from a tris-hydroxylated core and selective branching reactions of PEO chain ends. To this end, an AB(2)C-type branching agent was designed: the latter includes a chloromethyl (A) group for its covalent attachment to the arm ends, two geminal hydroxyls (B-2) protected in the form of a ketal ring for the growth of subsequent PEO generations by AROP, and a vinylic (C) double bonds for further functionalization of the interior of dendrimer-like PEOs. Reiteration of AROP and derivatization of PEO branches allowed us to prepare a dendrimer-like PEO of fourth generation with a total molar mass of 52,000 g center dot mol(-1), containing 24 external hydroxyl functions and 21 inner vinylic groups in the interior. A fifth generation of PEO chains was generated from this parent dendrimer-like PEO of fourth generation using a "conventional" AB(2)-type branching agent, and 48 PEO branches could be grown by AROP. The 48 outer hydroxy-end groups of the fifth-generation dendrimer-like PEO obtained were subsequently quantitatively converted into inert benzylic groups using benzyl bromide. The 21 internal vinylic groups carried by the PEO scaffold were then chemically modified in a two-step sequence into bromoester groups. The latter which are atom transfer radical polymerization (ATRP) initiating sites thus served to grow poly(tert-butylacrylate) chains. After a final step of hydrolysis of the tert-butyl ester groups, double, hydrophilic, dendrimer-like PEOs comprising 21 internal junction-attached poly(acrylic acid) (PAA) blocks could be obtained. Dynamic light scattering was used to determine the size of these dendrimer-like species in water and to investigate their response to pH variation: in particular, how the pH-sensitive complexation of EO and AA units affects their overall behavior.
dc.language.isoen
dc.publisherAmerican Chemical Society
dc.subject.enPOLYSTYRENE
dc.subject.enCOPOLYMERS
dc.subject.enCORED DENDRIMERS
dc.subject.enLIVING RADICAL POLYMERIZATION
dc.subject.enTERMINATOR MULTIFUNCTIONAL INITIATOR
dc.subject.enSTAR POLYMERS
dc.subject.enCONVENTIONAL MONOMERS
dc.subject.enSURFACE-PROPERTIES
dc.subject.enCHEMISTRY
dc.subject.enMACROMOLECULES
dc.typeArticle de revue
dc.identifier.doi10.1021/ja0631605
dc.subject.halChimie/Polymères
bordeaux.journalJournal of the American Chemical Society
bordeaux.page11551-11562
bordeaux.volume128
bordeaux.hal.laboratoriesLaboratoire de Chimie des Polymères Organiques (LCPO) - UMR 5629*
bordeaux.issue35
bordeaux.institutionBordeaux INP
bordeaux.institutionUniversité de Bordeaux
bordeaux.peerReviewedoui
hal.identifierhal-00368852
hal.version1
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00368852v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Journal%20of%20the%20American%20Chemical%20Society&rft.date=2006&rft.volume=128&rft.issue=35&rft.spage=11551-11562&rft.epage=11551-11562&rft.eissn=0002-7863&rft.issn=0002-7863&rft.au=FENG,%20Xiaoshuang&TATON,%20Daniel&BORSALI,%20Redouane&CHAIKOF,%20Elliot%20L.&GNANOU,%20Yves&rft.genre=article


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