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Solvatochromism of dye-labeled dendronized polymers of generation numbers 1-4: comparison to dendrimers.
Journal article

Solvatochromism of dye-labeled dendronized polymers of generation numbers 1-4: comparison to dendrimers.

  • Gstrein C Laboratory of Polymer Chemistry , Department of Materials , ETH Zurich , Vladimir-Prelog-Weg 5 , 8093 Zürich , Switzerland . Email: ads@mat.ethz.ch.
  • Zhang B Centre of Analysis and Synthesis , Lund University , P.O. Box 124 , SE-22100 Lund , Sweden . Email: baozhong.zhang@chem.lu.se.
  • Abdel-Rahman MA Chemistry Department , Faculty of Science , Assiut University , 71516 , Assiut , Egypt.
  • Bertran O Departament de Física Aplicada , EEI , Universitat Politècnica de Catalunya , Av. Pla de la Massa, 8 , 08700 Igualada , Spain.
  • Alemán C Departament de Física Aplicada , EEI , Universitat Politècnica de Catalunya , Av. Pla de la Massa, 8 , 08700 Igualada , Spain.
  • Wegner G Max-Planck-Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany.
  • Schlüter AD Laboratory of Polymer Chemistry , Department of Materials , ETH Zurich , Vladimir-Prelog-Weg 5 , 8093 Zürich , Switzerland . Email: ads@mat.ethz.ch.
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  • 2018-08-30
Published in:
  • Chemical science. - 2016
English Two series of dendronized polymers (DPs) of generations g = 1-4 with different levels of dendritic substitution (low and high) and a solvatochromic probe at g = 1 level are used to study their swelling behavior in a collection of solvents largely differing in polarity as indicated by the Kamlet-Taft parameters. This is done by measuring the UV-Vis spectra of all samples in all solvents and determining the longest wavelength absorptions (λmax). The λmax values fall into a range defined by the extreme situations, when the solvatochromic probe is either fully surrounded by solvent or completely shielded against it. The former situation is achieved in a model compound and the latter situation is believed to be reached when in a poor solvent the dendritic shell around the backbone is fully collapsed. We observe that solvent penetration into the interior of the DPs decreases with increasing g and does so faster for the more highly dendritically substituted series than for the less highly substituted one. Interestingly, the swelling of the more highly substituted DP series already at the g = 4 level has decreased to approximately 20% of that at the g = 1 level which supports an earlier proposal that high g DPs can be viewed as nano-sized molecular objects. Furthermore, when comparing these two DP series with a g = 1-6 series of dendrimers investigated by Fréchet et al. it becomes evident that even the less substituted series of DPs is much less responsive to solvent changes as assessed by the solvatochromic probe than the dendrimers, suggesting the branches around the (polymeric) core in DPs to be more densely packed compared to those in dendrimers, thus, establishing a key difference between these two dendritic macromolecules.
Language
  • English
Open access status
gold
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Persistent URL
https://sonar.ch/global/documents/99684
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