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

Abstract

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 N(2) flow, then the resulting poly(sarcosine) is used in situ as the macro-initiator for the ring-opening polymerization (ROP) of ε-caprolactone using tin(II) octanoate as a catalyst. The degree of poly-merization of each block is controlled by various feed ratios of monomer/initiator. The diblock copolymers with controlled molecular weight and narrow molecular weight distributions (Đ(M) < 1.2) are characterized by (1)H NMR, (13)C 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.