Switchable PTH(25-37) fibrillation via isomerization of photoswitchable motifs
André Paschold
and
Effects of topological constraints in polymer melts on crystallization and structure formation
Afiq Bin Anuar
date: 22.2.22 15.00-16.30
online via zoom
chair: Matthias
Switchable PTH(25-37) fibrillation via isomerization of photoswitchable motifs
André Paschold
Amyloidogenic peptides are a highly interesting class of proteins, due to their importance in context of diseases e.g. Alzheimer or Parkinson disease and also as well defined-functional peptides in different organisms. All those peptides have the ability to form supramolecular structures, so called fibrils. In our research, we investigate the process of fibril formation specifically for the human PTH. Therefore, we design photoswitches with specific photophysical properties and incorporate them via SPS in different parts of the peptide.
Effects of topological constraints in polymer melts on crystallization and structure formation
Afiq Bin Anuar
Generally, there are two types of semicrystalline polymers namely, crystal-fixed and crystal-mobile polymers. These classifications depend on the presence or absence of intracrystalline chain dynamic (ICD) within the crystal structure. In crystal-fixed polymers, slowed to absence ICD was reported while crystal-mobile exhibits much faster ICD. The difference in ICD leads to different semicrystalline morphological in both types of polymers. It was observed that crystal-fixed PCL exhibits well-defined distribution crystal thickness with a thick amorphous layer. In contrast, crystal-mobile PEO has a broad distribution of crystalline thickness with thin well defined amorphous layers. In 2018, R. Kurz [1] reported no disentanglement in amorphous layer during crystallization in crystal-fixed PCL which may explained the well-defined crystal thickness and thick amorphous layer features. We believe this should be contrary to crystal-mobile case which explained the above-mentioned morphological features of crystal-mobile polymer. Thus, in this seminar, one of our future works on implementing PEO oligomer dilution to study the role of entanglement pressure in the amorphous phase to crystal mobile PEO crystal lamella will be discussed. An introductory project of investigating ICD of PBS polymer to classify the polymer types and simultaneously to familiarise with the concept that will be used in future works will be presented.
[1] R. Kurz, M. Schulz, F. Scheliga, Y. Men, A. Seidlitz, T. Thurn-Albrecht, and K. Saalwächter,
Interplay between Crystallization and Entanglements in the Amorphous Phase of the Crystal-Fixed Polymer Poly(epsilon-caprolactone)
Macromolecules 51, 5831 (2018)
