Molecular dynamics simulation of brushes formed by star polyelectrolytes under theta solvent conditions |
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Authors: | Kalliopi Miliou Leonidas N Gergidis Costas Vlahos |
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Institution: | 1. Department of Chemistry, University of Ioannina, Ioannina, Greece;2. Department of Materials Science & Engineering, University of Ioannina, Ioannina, Greece |
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Abstract: | Using molecular dynamics simulations, we have studied polyelectrolyte brushes formed by partially or fully charged star polymers tethered on a planar surface under theta solvent conditions. The diagram of states for salt‐free solutions differs in the location of osmotic regime (OB) compared with the respective diagram reported by Borisov and Zhulina. In contrast, simulation results dictate that the OB regime appears for values of the ratio F /α ?1/2 lB ?1 much larger than unity, which is the threshold of counterion localization, with F denoting the branch functionality, α the charged units fraction and lB the Bjerrum length. The simulation results support that the brush height scaling laws H ~ α 2 lB F 1.049S 3s ?1 and H ~ α0.302 F 0.23S for the charged Pincus Brush (PB) and osmotic (OB) regimes, respectively, where S is the spacer length and s is the grafted area per star chain. The respective theoretical scaling laws are H ~ α 2 lB F 1.88S 3s ?1 and H ~ α 1/2 F 0.44S . © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 1110–1117 |
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Keywords: | interfaces molecular dynamics polyelectrolyte brush polyelectrolytes star polymer |
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