Determination of the interaction parameter and topological scaling features of symmetric star polymers in dilute solution
| Autor: | Gregory Beaucage, Nikos Hadjichristidis, Durgesh K. Rai, Peter A. Beaucage, Ramnath Ramachandran, Kedar Ratkanthwar |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
chemistry.chemical_classification
Physics Quantitative Biology::Biomolecules Polymers Scattering Polymer Xylenes Neutron scattering Topology Branching (polymer chemistry) Solutions Condensed Matter::Soft Condensed Matter Neutron Diffraction symbols.namesake X-Ray Diffraction chemistry Scattering Small Angle symbols Biological small-angle scattering Random phase approximation Scaling Astrophysics::Galaxy Astrophysics Debye |
| Zdroj: | Physical Review E. 92 |
| ISSN: | 1550-2376 1539-3755 |
| Popis: | Star polymers provide model architectures to understand the dynamic and rheological effects of chain confinement for a range of complex topological structures like branched polymers, colloids, and micelles. It is important to describe the structure of such macromolecular topologies using small-angle neutron and x-ray scattering to facilitate understanding of their structure-property relationships. Modeling of scattering from linear, Gaussian polymers, such as in the melt, has applied the random phase approximation using the Debye polymer scattering function. The Flory-Huggins interaction parameter can be obtained using neutron scattering by this method. Gaussian scaling no longer applies for more complicated chain topologies or when chains are in good solvents. For symmetric star polymers, chain scaling can differ from ν=0.5(d(f)=2) due to excluded volume, steric interaction between arms, and enhanced density due to branching. Further, correlation between arms in a symmetric star leads to an interference term in the scattering function first described by Benoit for Gaussian chains. In this work, a scattering function is derived which accounts for interarm correlations in symmetric star polymers as well as the polymer-solvent interaction parameter for chains of arbitrary scaling dimension using a hybrid Unified scattering function. The approach is demonstrated for linear, four-arm and eight-arm polyisoprene stars in deuterated p-xylene. |
| Databáze: | OpenAIRE |
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