We indicate elaborate alteration of colloidal architecture self-associated from block-copolymer excipients with versatile molecular geometry, which leads to the different kinetic properties for the pH-triggered release of cisplatin. Atom-transfer radical polymerization was employed as a controlled synthetic method for the block-copolymer, which comprise the cisplatin-binding poly(acrylic acid) block joined either a small mPEG-grafted poly(methacrylate) to generate a brush-type structure or a simple linear mPEG segment. Upon the coordination of Pt^II as an active pharmacophore of cisplatin, the resulting Pt^II-encapsulated nanoparticles exhibited micelle-like core/shell structures with various kinetic properties for Pt^II-mediated self-association as well as acid-triggered drug release processes, which further allows us to explore the molecular geometry-colloidal property relationship through the structural determination of colloidal architecture.