Photo-controlled/living radical polymerization of 2-(dimethylamino)ethyl methacrylate using 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl as a mediator

Abstract

The photo-controlled/living radical polymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA) was attained using 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl as the mediator and (2RS,2′RS)-azobis(4-methoxy-2,4-dimethylvaleronitrile) (r-AMDV) as the initiator. The bulk polymerization of DMAEMA produced a polymer with a comparatively narrow molecular weight distribution below 1.6. The first-order time conversion plots showed a linear increase. The molecular weight of the resulting polymer also increased with an increase in the monomer conversion. The molecular weights of the resulting polymers were in good agreement with the theoretical molecular weights. A linear correlation was also obtained for the plots of the molecular weight vs. the reciprocal of the initial concentration of r-AMDV. The GPC analysis demonstrated the living nature of the polymerization based on the fact that the curves were shifted to the higher molecular weight side without deactivation as the conversion increased.

Light-Controlled Radical Polymerization: Mechanisms, Methods, and Applications

“…Yoshida reported the photo-CRP of various monomers accelerated by redox-active additives (e.g., iodonium salts, sulfonium salts, and iron–arene complex) with 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (MTEMPO) at ambient temperature. − The living nature of these systems was confirmed with kinetics studies; however, compared to traditional NMP methods, the dispersity indices of polymers obtained via these methods were typically higher. Nonetheless, the authors showed that the polymerization could be immediately stopped and restarted by turning the light source off and on for one cycle. , The authors suggested a unique mechanism wherein the additive accelerates the polymerization rate by reversibly oxidizing the nitroxide to an oxoaminium salt. − Back electron transfer regenerates MTEMPO, which can then cap a propagating radical to reform a dormant chain.…”

Morphological stability of worm-like vesicles consisting of amphiphilic diblock copolymer against external stress

“…[22] Poly(2dimethylaminoethyl methacrylate) (PDMAEMA) was prepared by the photo NMP. [28] Methanol (MeOH) was refluxed over magnesium with a small amount of iodine for several hours, and then distilled. Distilled water was purchased from Wako Pure Chemical Industries and used without further purification.…”

Advances in Polymerizations Modulated by External Stimuli

“…Until 2008, examples of photo-NMP had shown control only over initiation and not over propagation. The incorporation of photoredox additives (e.g., iodonium salts, sulfonium salts, and Fe–arene complexes) with TEMPO derivatives gave rise to photoswitchable NMP under irradiation with a 500 W high-pressure mercury lamp. − These photoredox/TEMPO systems exhibit living polymerization activity and have been shown to control the propagation through the performance of one in situ on/off cycle. It is hypothesized that the photoredox additive enables polymerization control by reversibly oxidizing the nitroxide to an oxoaminium salt. − …”