Dendrimer-influenced supramolecular structure formation of block copolymers
The water content-dependent supramolecular structure formation of polystyrene-block-poly(acrylic acid) (PS-b-PAA) copolymer in the presence of a fourth-generation amine-terminated poly(amido amine) dendrimer (PAMAM) is investigated by dynamic light scattering, turbidity measurements, and transmissio...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1999. - 23(2007), 21 vom: 09. Okt., Seite 10732-40 |
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| Weitere Verfasser: | , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2007
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article |
| Zusammenfassung: | The water content-dependent supramolecular structure formation of polystyrene-block-poly(acrylic acid) (PS-b-PAA) copolymer in the presence of a fourth-generation amine-terminated poly(amido amine) dendrimer (PAMAM) is investigated by dynamic light scattering, turbidity measurements, and transmission electron microscopy. The solvent system for this study is a mixture of dioxane/THF and water. A very complex turbidity profile is observed with increasing water content in the system and is explained by the presence of various aggregated structures based on strong interactions between the amine-containing dendrimers and the poly(acrylic acid) blocks of the polymer. The onset of the self-assembly of single chains of PS-b-PAA (primary structure) into single and multiple dendrimer core inverse micelles (secondary structure) is detected as very low water contents of cw < 2% wt (cwc). These micelles consist of dendrimers coated with PAA blocks, which are connected to the corresponding PS chains that form the corona. Further addition of water leads to an association of these micelles into compound multiple dendrimer core inverse micelles (tertiary structure) in the range of cw = approximately 6 to approximately 10% wt. At still higher water content, some of the acrylic acid chains of the block copolymer move from the vicinity of the dendrimer to the outside of the aggregates, resulting in a decrease in the size of the formed structures and the acquisition of progressively increasing hydrophilic character of the aggregates. Multiple dendrimer core inverse onion micelles are formed, which agglomerate into compound multiple dendrimer core inverse onion micelles at cw = approximately 12 to approximately 18% wt. Above this water content, vesicular structures are formed. The complexity is unusual for block copolymer systems and illustrates the importance of strong interactions in structure formation |
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| Beschreibung: | Date Completed 13.11.2007 Date Revised 02.10.2007 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1520-5827 |