Uniform polystyrene hollow particles were prepared successfully by employing SPG (Shirasu porous glass) emulsification technique. The oil phase composed of monomer [styrene (St) and N

N-dimethylamino ethylmethacrylate (DMAEMA)]

hexadecane (HD) and initiator was permeated through the uniform pores of SPG membrane into the aqueous phase (containing stabilizer

emulsifier and water-soluble inhibitor ) by a gas pressure to form uniform droplets. The droplets were then polymerized at 70℃. It was found that the hollow particles were obtained by adding a small amount of DMAEMA into the oil phase and by using NaNo2 as the water-soluble inhibitor

while only one-hole particles were obtained without adding DMAEMA

or when using diaminophenylene (DAP) or hydroquinone (HQ) as the inhibitor. The formation mechanism was discussed by the view of interfacial tensions between polymer and aqueous phase

HD and aqueous phase

and HD and polymer. Further more

it was found that hollow particles can be obtained even when DMAEMA content in the oil phase was very low

by increasing HD to high value.