Thermoresponsive Polypeptoid‐Coated Superparamagnetic Iron Oxide Nanoparticles by Surface‐Initiated Polymerization

Thermoresponsive polypeptoids are promising candidates for medical applications due to their biomimetic properties. When such polymers are grafted on magnetic nanoparticles, materials can be obtained that combine a temperature‐triggered solubility transition with magnetic extraction. The synthesis of monodisperse, superparamagnetic iron oxide nanoparticles is described with densely surface‐grafted polypeptoid shells that have tunable thermoresponsive colloidal stability. The synthesis combines ligand exchange with controlled surface‐initiated polymerization of N‐substituted N‐carboxyanhydrides for the preparation of well‐defined core–shell nanoparticles.