Solution behavior of 4-arm poly(tert-butyl acrylate) star polymers

This paper reports the synthesis of 4-arm poly(tert-butyl acrylate) stars of different molar masses up to 106 g/mol by the “core-first” method using ATRP. All obtained stars have a monomodal and narrow molar-mass distribution (<1.2). The dilute-solution properties of these star polymers were investigated in good solvents (tetrahydrofuran and acetone). Gel permeation chromatography and dynamic and static light scattering were used to measure the hydrodynamic properties including intrinsic viscosity [η], radius of gyration Rg, hydrodynamic radius Rh, second virial coefficient A2 and diffusion coefficient D0. These data were used to establish relationships between these parameters and the molar mass of 4-arm poly(tert-butyl acrylate) stars. The branching parameters g and g′ and the shape factor ρ were calculated for all obtained star polymers.