The photograft polymerization on porous substrate

poly(ethylene terephthalate) (PET) nucleopore membranes

was investigated by directly observing the configuration under SEM．The result of photografting strongly depends on the grafting methods and the nature of substrate membranes

such as pore size and pore shape

and different membrane configurations were obtained

for instance

decreasing pore size

pore-covering and pore-filling．To topside method

a standard straight pore shape is adverse to grafting inside pores

especially to small pore size membranes (0.4 μm)

and it tends to give a pore-covering effect i．e．graft mainly occurs on the membrane surface rather than inside the membrane pores. The cone-shaped pores have much effective grafting area and are mole easily filled than straight pores．To large pore size membrane (5 μm)

crosslink agent is necessary to form a thick graft layer on the pore wall．A new backside adsorption method was applied in which the reaction solution was adsorbed into pores from the membrane backside owing to the capillarity and grafting polymerization was restricted inside pores. It is suitable for the synthesis of small pore diameter pore-filling membrane without changing the membrane surface characters

such as the photograft pore-filling modification of ultrafiltration membrane．Membrane pore size could be adjusted via selecting correct photografting technique and grafting degree (Dg)．With the increase of grafting degree

the pore size and water flux of grafted membranes are decreased．The results of photograft polymerization on nucleopore membranes

a model of ideal membrane

provide valuable information for the photografting modification of other membranes.