Synthesis And Application Of Amphiphilic Block Copolymers

Amphiphilic block copolymer polystyrene-b-polyacrylic acid (PS-b-PAA) and poly(e-caprolactone)-b-polyacrylic acid (PCL-b-PAA) with narrow molecular weight distribution were prepared by atom transfer radical polymerization with CuBr/PMDETA catalytic system and ring-opening polymerization with octoate stannous as catalyst. The characteristic groups, molecular weights and distributions of the initiator agents and block copolymers were obtained by GPC and’H NMR. Two methods of bulk polymerization and solution polymerization were used to compare their impact on the degree of polymerization.Ordered porous films were fabricated by using PS-b-PAA as the film-forming material and chloroform or carbon disulfide as the solvents via the breath-figure (BF) method. The surface morphologies were shown by SEM observation. The impact of chain length, solution concentration and solvent type were studied on film-forming effect.Titanium dioxide nanospheres with visible light photocatalytic activity were synthesized via sol-gel approach using an amphiphilic block copolymer PS-b-PAA as template at room temperature in toluene. The TiO2nanospheres had diameters ranging from200to500nm. The formation of Ti-O-C bonds upon carbonization was as a result of visible light absorption. The photodegradation experiments showed that the TiO2nanospheres calcinated at600℃had the best visible-light photocatalytic activity.