One-pot glovebox-free synthesis, characterization, and self-assembly of novel amphiphilic poly(sarcosine-b-caprolactone) diblock copolymers

Novel amphiphilic polypeptoid-polyester diblock copolymers based on poly(sarcosine) (PSar) and poly(ε-caprolactone) (PCL) are synthesized by a one-pot glovebox-free approach. In this method, sarcosine N-carboxy anhydride (Sar-NCA) is firstly polymerized in the presence of benzylamine under N₂ flow, then the resulting poly(sarcosine) is used in situ as the macroinitiator for the ring-opening polymerization (ROP) of ε-caprolactone using tin(II) octanoate as a catalyst. The degree of polymerization of each block is controlled by various feed ratios of monomer/initiator. The diblock copolymers with controlled molecular weight and narrow molecular weight distributions (D strok sign_M < 1.2) are characterized by ¹H NMR, ¹³C NMR, and size-exclusion chromatography. The self-assembly behavior of PSar-b-PCL in water is investigated by dynamic light scattering (DLS) and transmission electron microscopy. DLS results reveal that the diblock copolymers associate into nanoparticles with average hydrodynamic diameters (D_H) around 100 nm in water, which may be used as drug delivery carriers. Novel amphiphilic polypeptoid-polyester diblock copolymers composed of poly(sarcosine) (PSar) as the hydrophilic block and poly(ε-caprolactone) (PCL) as the hydrophobic block are synthesized by a one-pot glovebox-free approach. PSar is firstly used as macroinitiator for the ring-opening polymerization (ROP) of ε-caprolactone monomer to obtain PSar-b-PCL copolymers with controlled molecular weight and narrow molecular weight distributions. PSar-PCL can self-assemble into nanoparticles in aqueous solution.