Cationic Polymerization of Vinyl Ethers Controlled by Visible Light

Abstract

Photoinitiated cationic polymerizations are widely used in industrial processes; however, gaining photocontrol over chain growth would expand the utility of these methods and facilitate the design of novel complex architectures. We report herein a cationic polymerization regulated by visible light. This polymerization proceeds under mild conditions: a combination of a metal-free photocatalyst, a chain-transfer agent, and light irradiation enables the synthesis of various poly(vinyl ether)s with good control over molecular weight and dispersity as well as excellent chain-end fidelity. Significantly, photoreversible cation formation in this system enables efficient control over polymer chain growth with light.

Hyperbranched Polymers by Light‐Induced Self‐Condensing Vinyl Polymerization

“…[17] Such lightinduced processes represent several advantages over conventional thermal tech niques regarding the level of control since they can be accurately moderated in terms of wavelength, polarization direction, and intensity, allowing spatial and temporal of the reactions. [18] Light is also used in polymerization reactions following different mechanisms including radical, [19] cationic, [20][21][22] anionic, [23] and stepgrowth polymerization [24] routes. In recent years, light induced processes are also successfully employed in controlled/ living polymerization [25,26] and click reactions [27] for the forma tion of various complex macromolecular architectures.…”

Photoinitiated Metal Free Living Radical and Cationic Polymerizations

“…In an interesting study, Fors and coworkers [73] demonstrated a new cationic RAFT procedure where chain growth is regulated by light. In the process, a suitable photocatalyst, 2,4,6-tris(pmethoxyphenyl)pyrylium tetrafluoroborate, oxidizes chain transfer agent to form carbocations participating the RAFT process (Scheme 9).…”

Controlling the Ring‐Opening Polymerization Process Using External Stimuli

“…Ideally, a carefully chosen stimulus could enable site‐specific transformation of the catalytic center through allosteric, redox, acid/base, electrochemical, light, mechanochemical modulation, and so on . Recently, tremendous advances in the burgeoning field of the switchable polymerization have been reported such as controlled radical polymerization, cationic polymerization, ring‐opening metathesis polymerization, ring‐opening polymerization (ROP) and olefin polymerization . Among the above‐mentioned various polymerizations, the switchable ROP has attracted much attention, emerging as a powerful strategy for the development of eco‐friendly biodegradable polymers, which can potentially serve as alternatives to petroleum‐based polymers.…”