Photoinduced organocatalyzed controlled radical polymerization feasible over a wide range of wavelengths

Abstract

In this paper, photoinduced controlled radical polymerization (PI-CRP) provided excellent temporal and spatial control over a wide range of irradiation wavelengths (450–850 nm). Polymers with controllable molecular weight and narrow molecular weight distribution were synthesized using amphiphilic ethidium iodide (EI) as a catalyst and 2-iodine-2-methylpropanenitrile as an initiator in controlled radical polymerization of hydrophilic methacrylates in aqueous solution and oleophilic methacrylates in bulk under the irradiation of white, blue, green, red, and near-infrared (NIR) light, and sunlight. Moreover, no polymerization occurred without light irradiation, indicating that the polymerization was an ideal photo “on”–“off” switchable system. The obtained polymers have high chain-end fidelity and act as macroinitiators to generate various block copolymers. The feasibility of polymerizations under the irradiation of such a wide range of wavelengths by an organic catalyst both in bulk and aqueous solutions was an unprecedented feature. The advantages of this polymerization included simple preparation of catalysts, adsorption of broadband light, ease of operation and applicability to a wide range of polymer designs.