Order-disorder transition of nanocomposites; Polystyrene-block-poly(methyl methacrylate) with Pd nanoparticles

Zhao, Y.

no journal, , 

We studied how the palladium nanoparticles, (Pd)ns, incorporated into poly(styrene)-block-poly(methylmethacylate) (PS-b-PMMA) block copolymer (bcp), alter its order-disorder transition (ODT). The (Pd)ns were incorporated into the lamellar template of PS-b-PMMA by the thermal reduction of palladium acetylacetonate, dissolved uniformly in the bcp in the disordered state. The ODT behavior of the neat bcp and the nanocomposites are investigated by small angle X-ray scattering as a function of temperature. We found the incorporation of a very small amount of (Pd)ns significantly increased the ODT temperature by about 8C, which is due to the stronger attractive interactions of (Pd)ns with PS block chains than with PMMA block chains, which increases the net effective segregation power between PS and PMMA block chains and hence stabilizes the ordered lamellae.