The beauty of block and gradient poly-2-oxazolines as it seen by SANS and NSE

by Prof. Sergey Filippov (Department of Chemistry, University of Reading)

Monday 31 Jan 2022, 14:30 → 15:30 Europe/Berlin

Zoom Webinar

The internal structure of amphiphilic block and gradient co poly(2-oxazolines) based on the hydrophilic poly(2-methyl-2-oxazoline) (PMeOx) and the hydrophobic poly(2-phenyl-2-oxazoline) (PPhOx) was studied in water and water-ethanol mixtures by Small-Angle X-ray Scattering (SAXS), Small-Angle Neutron Scattering (SANS), and Neutron Spin Echo experiments (NSE).  Contrast matching small angle neutron scattering (SANS) experiments revealed that block copolymers form micelles with a uniform density profile of the core. In contrast to popular assumption, the outer part of the core of the gradient copolymer micelles has a distinctly higher density than the middle of the core. We attribute the latter finding to back-folding of chains resulting from hydrophilic-hydrophobic interactions, leading to a new type of micelles that we refer to as micelles with a “bitterball-core” structure.