PEG‐Amine‐Initiated Polymerization of Sarcosine N‐Thiocarboxyanhydrides Toward Novel Double‐Hydrophilic PEG‐b‐Polysarcosine Diblock Copolymers

Amino acid N ‐thiocarboxyanhydride (NTA), the thioanalog of N ‐carboxyanhydride (NCA), is much more stable than NCA against moisture and heat. The convenient monomer synthesis without rigorous anhydrous requirements makes the ring‐opening polymerization of NTA a competitive alternative to prepare polypeptoid‐containing materials with potential of large‐scale production. Polysarcosines (PSars) with high yields (>90%) and low polydispersities (<1.2) are synthesized from sarcosine N ‐thiocarboxyanhydride (Sar‐NTA) at 60 °C initiated by primary amines including poly(ethylene glycol) amine (PEG–NH 2 ). The lengths of PSar segments are controlled by various feed ratios of Sar‐NTA to initiator. PEG‐ b ‐PSar products, a class of novel double‐hydrophilic diblock copolymers, are effective in stabilizing oil‐in‐water emulsions at nano‐ and microscale, which demonstrates promising encapsulation applications in food, cosmetics, and drug delivery. Due to the different solubility of PEG and PSar blocks, PEG‐ b ‐PSar copolymers form micelles in organic solvents with the capability to incorporate metal cations including Cu 2+ and Ni 2+ . image