Stimuli-Responsive Aggregation of High Molar Mass Poly(N,N-Diethylacrylamide)-b-Poly(4-Acryloylmorpholine) in Tetrahydrofuran.

The self-assembly of block copolymers constitutes a timely research area in polymer science with implications for applications like sensing or drug-delivery. Here, the unprecedented aggregation behavior of high molar mass block copolymer poly(N,N-diethylacrylamide)-b-poly(4-acryloylmorpholine) (PDEA-b-PAM) (Mn >400 kg mol-1 ) in organic solvent tetrahydrofuran (THF) is investigated. To elucidate the aggregation, dynamic light scattering, cryo-transmission electron microscopy, and turbidimetry are employed. The aggregate formation is assigned to the unprecedented upper critical solution temperature behavior of PAM in THF at elevated concentrations (> 6 wt.%) and high molar masses. Various future directions for this new thermo-responsive block copolymer are envisioned, for example, in the areas of photonics or templating of inorganic structures.