Dresden 2017 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 68: Hydrogels and Microgels II
CPP 68.6: Vortrag
Freitag, 24. März 2017, 11:30–11:45, ZEU 260
Uptake and stability of pH-Sensitive Gold Nanoparticles (AuNPs) in Thermoresponsive Polymer Brushes — •Dikran Kesal1, Patrick Krause1, Marcus Trapp2, and Regine von Klitzing1 — 1TU Berlin, 10623 Berlin, Germany — 2Helmholtz Zentrum Berlin, 14109 Berlin, Germany
Polymer brushes are polymers tethered to a surface or interface by one end, which at sufficiently high grafting densities show a stretched conformation away from the surface. Many of its applications, for e.g. sensoric and catalysis, involve interaction with particles of some kind, so understanding the interactions between nanoparticles and polymer brushes is of great importance. Embedding nanoparticles, e.g. AuNPs, in polymer brushes result in nanocomposite materials with novel optical properties.
In this work, the assembly of charge switchable AuNPs inside neutral charged Poly(N-isopropylacrylamide) (PNIPAM) brushes will be discussed. The 5 nm AuNPs are capped with mercaptopropionic acid (MPA, pKa 5.5) which bears a carboxylate group and is either protonated (uncharged) or deprotonated (negatively charged) depending on the pH. While some recent efforts have been made in terms of particle uptake and distribution in weakly (PDMAEMA) and strongly (PMETAC) charged polymers due to electrostatic interaction between particle and brush. While PNIPAM brushes are neutral charged and can only interact via H-bonding with the AuNPs, here the focus is on understanding how protonating and deprotonating of the AuNPs affect particle loading, distribution and stability in PNIPAM brushes.