Title： Membrane-forming block copolymers with degradable blocks and linkers : Synthesis and self-assembly

Time：10:00 AM, April 28, 2026

Location：C3-c204, GuangzhouInternational Campus,SCUT

Speaker：Jeppe Madsen（Technical University of Denmark）

Abstract：

The synthesis, characterization and self-assembly behaviour of two types of amphiphilic block copolymer systems are presented: The first system comprises block copolymers of hydrophilic poly(ethylene glycol), PEG, and hydrophobic, crystalline poly(caprolactone), PCL. Specifically, a range of PEG-b-PCL deblock copolymers and PEG-b-PCL-b-PEG triblock copolymers were prepared with comparable hydrophilic (PEG) mass fractions of around 30 %. Self-assembly via direct hydration yielded mixed phases of micelles (spherical and/or worm-like) and vesicles, along with larger aggregates. The membranes of the vesicles based on diblock copolymers were thicker than those based on triblock copolymers for PCL blocks of comparable degrees of polymerization. This behaviour could be correlated with the restraints imposed on the crystallisation of PCL by the PEG blocks.

The second system comprises triblock copolymers of PEG and amorphous, hydrophobic poly(dimethyl siloxane), PDMS. These PEG-b-PDMS-b-PEG triblock copolymers were designed so that one PEG arm is connected to the PDMS block via a silyl ether bond that is prone to hydrolysis, whereas the other PEG arm is connected to PDMS through a hydrolytically stable carbosilane bond. The initial triblock had a hydrophilic (PEG) mass fraction of approximately 31 %, whereas full hydrolysis of the silyl ether leads to a PEG-b-PDMS diblock copolymer with a hydrophilic mass fraction of 22 % as well as free PEG. Thus, slow hydrolysis following direct hydration resulted in vesicles with an average diameter of 55 nm and a relatively narrow size distribution. The formation of such small vesicles is difficult to achieve by other means.