PhotoATRP Approach to Poly(methyl methacrylate) with Aggregation-Induced Emission

In the past decades, polymeric fluorescent materials with aggregation-induced emission (AIE) properties play important roles in the fields of biomedical and analytical chemistry, and the synthesis of well-defined polymers under mild conditions is in demand. In this report, narrowly distributed poly(methyl methacrylate)s (PMMAs) with AIE properties were prepared in mild conditions using 4-(1,2,2-triphenylvinyl)benzyl 2-bromo-2-phenylacetate (TPE-BPA), a novel initiator with an AIE-based functional group. This approach resulted in PMMAs with a fluorescent tag at the chain end (TPE-PMMA). Specifically, a high efficiency of initiation was observed using a low amount of air-stable copper(II) bromide/tris(2-pyridylmethyl)amine (CuIIBr2/TPMA) as a photocatalyst under the irradiation of LED@405 nm. Moreover, the TPE presented in the system did not affect the polymerization kinetics of MMA and the temporal control. The dispersities of the obtained PMMAs were as low as 1.12. Interestingly, TPE-PMMA with narrow dispersity was also obtained (Mw/Mn < 1.25) in the presence of air. Regarding the fluorescent properties of TPE-PMMAs, it was observed that their AIE intensities increased with the molecular weights. Moreover, they could also be used to probe the increased viscosity of the solution, indicating their potential of synthesizing functional sensors. The approach proposed in this work is convenient to prepare poly(methacrylate)s with well-defined structures in the presence of AIE-based fluorescent tags, and it thus paves a new way for the rational design of AIE-functionalized polymeric materials.