New polymethylene-based AB₂ star polymers with well-defined architecture and various components were synthesized using a combination of polyhomologation of ylides and atomic transfer radical polymerization (ATRP). The chain structures of polymethylene-b-(polystyrene)₂ (PM-b-(PS)₂) and polymethylene-b-(poly(methyl methacrylate))₂ (PM-b-(PMMA)₂) were characterized through ¹H NMR, GPC and FT-IR. The porous films of such star copolymers were fabricated via a static breath-figure (BF) process. The influence of polymer molecular weight, solution concentration and environmental temperature on the morphology of such block copolymer films was investigated. The porous surface of such a film presents hydrophobic behaviour with a static water-droplet contact angle of ca. 108°. The electrospinning of PM-b-(PS)₂ was performed using CHCl₃ as a solvent and the wrinkle-like polymer particles with nanopores on their surface were obtained.