Architecture of hyperbranched polymers consisting of a stearyl methacrylate sequence via a living radical copolymerization

The living radical photocopolymerization of 2-(N,NN,N-diethyldithiocarbamyl)ethyl methacrylate (DCEM) as inimer and stearyl methacrylate (STM) as comonomer was carried out under UV irradiation. According to this method, we synthesized hyperbranched polymers (HP) consisting of a STM sequence having a long alkyl side chain. The gel permeation chromatography distribution of hyperbranched polymers had a unimodal pattern. The reactivity ratios (r1=0.79r1=0.79 and r2=0.81r2=0.81) were estimated by the Kelen–Tüdös method (DCEM: [M]1 and STM: [M]2). These values indicated that the two monomers showed almost equal reactivity toward propagating radical species. The radius of gyration (Rg)(Rg) and the hydrodynamic radius (Rh)(Rh) of copolymers were determined by static and dynamic light scattering (SLS and DLS), and the values of Rg/RhRg/Rh changed from 0.79 to 1.59 with an increment of the feed amount of STM. These results indicated that the copolymer structures changed from hard spheres to loose branched molecules in solution.

We presented hyperbranched polymer syntheses consisting of a stearyl methacrylate (STM) sequence having long alkyl side chains by photoinduced living radical copolymerization of 2-(N,NN,N-diethyldithiocarbamyl)ethyl methacrylate (DCEM) as inimer with STM under UV irradiation. The reactivity ratios (r1=0.79r1=0.79 and r2=0.81r2=0.81; DCEM [M]1 and STM [M]2) indicated that the two monomers showed almost equal reactivity towards propagating radical species. The copolymer structures were able to change from hard spheres to loosely branched molecules in solution. Not only degree of branching but also steric hindrance of long alkyl chains of poly(stearyl methacrylate) (PSTM) (brush-like sequence) contributed to the compact nature of hyperbranched polymers.Schematic illustration hyperbranched polymersFigure optionsDownload as PowerPoint slide