Nanoparticle surfactants as a route to bicontinuous block copolymer morphologies.

graphical abstract
Kim, B.J.; Fredrickson, G.H.; Hawker, C.J.; Kramer, E.J.;
23, 7804-7809.

The surface chemistry of nanoparticles can be modified so that these particles behave like surfactants and localize at interfaces between two fluids. We demonstrate that small volume fractions P of such surfactant nanoparticles added to lamellar diblock copolymers lead initially to a decrease in lamellar thickness with P, a consequence of decreasing interfacial tension, up to a critical value of P, beyond which the block copolymer adopts a bicontinuous morphology. These bicontinuous morphologies have stable domain spacings below 100 nm that further decrease with increasing P and offer new routes to nanoscopically engineered polymer films with potential photovoltaic, fuel cell, and battery applications.