Conveners
Polymers and Criticality
- Fanni Juranyi (Paul Scherrer Institute)
- Olaf Holderer
Dynamics of polymer melts is multiscale, extending from the local monomer motion to diffusion over the distances beyond the size of the whole chain. For relatively short chains (M<Mc, Me), where the inter-chain interactions are not pronounced, the Rouse model provides a good description with physically realistic parameters of the chain dynamics. Dynamics of long or strongly entangled chains...
Using neutron spin echo spectroscopy the dynamics of short unentangled tracer chains in the melt of a highly entangled polymer matrix has been investigated [1]. Independent of the tracer chain length the center of mass mean square displacement (MSD) is sub-diffusive at short times and crosses over to Fickian diffusion at longer times. The obtained diffusion coefficients on the nm scale agree...
After the static criticality of 3-picolin/D$_2$O and 3-picolin/D$_2$O/sodium tetraphenylborate having been identified to be of the 3d-Ising and 2d-Ising type, respectively, we investigated the dynamic criticality of the two systems using dynamic light scattering and neutron spin-echo spectroscopy. The first method yields the hydrodynamic diffusivity, while the second method observes the...
Protein nanoparticles can outperform polymer nanoparticles due to their versatility, biodegradability and low immunogenicity. We have exploited our previous experience in the preparation and characterization of synthetic unimolecular single-chain nanoparticles (SCNPs) to synthesize polypeptide SCNPs based on proteins. The conformational changes due to chain folding or collapse, i.e, an...
