Star polymers show great promise for a range of applications, including drug delivery and advanced coatings. Their unique solution properties and high functionality also make them attractive building blocks for the preparation of nanostructured thin films. This article describes the preparation of a poly(acrylic acid) (PAA)-based core cross-linked star (CCS) polymer by the “arm first” approach and its assembly into multilayered films by the layer-by-layer (LbL) method. Synthesis of the PAA star polyelectrolyte was achieved by preparing an acid protected polymer, poly(tert-butyl acrylate), by atom transfer radical polymerization and reacting it with a divinyl monomer (divinylbenzene), followed by deprotection. The PAA star polyelectrolyte displayed pH-responsive behavior in solution, as studied by dynamic light scattering, where a reversible size change was observed in response to pH changes. At pH 8–10, the acrylic acid segments are fully charged, adopting a more stretched conformation, and larger diamete...