Synthesis of porous poly(styrene-co-acrylic acid) microspheres through one-step soap-free emulsion polymerization: Whys and wherefores

► One-step soap-free emulsion polymerization for the synthesis of porous microspheres is reported. ► Phase separation between the hydrophilic and the hydrophobic segments is ascribed to the pore formation. ► 150-240 nm porous microspheres containing 4-25 nm pores are synthesized. ► Advantages including well-controlled pore size and convenience are demonstrated.