Prospects of nanorods as an emulsifying agent of immiscible blends

Immiscible binary fluids containing rigid nanorods that are preferentially immersed in one of the two fluids are systematically investigated via dissipative particle dynamics simulations. For sufficiently high volume fraction and/or aspect ratio, nanorods lead to a pronounced slowing down of the phase separation process, and yield microphase-separated structures with a characteristic length scale that decreases as either the nanorods length or their volume fraction is increased. The slowing down of the dynamics is attributed to a disordered jamming of the nanorods in the preferred component and a dramatic reduction in their diffusion due to kinetic conformational hindrance. The final characteristic length scale of the dispersion, reduced by the nanorods length, is found to depend only on Onsager's dimensionless parameter psi nu, where psi and nu are the nanorods volume fraction and aspect ratio, respectively. These results indicate that nanorods may be used as an effective emulsifying agent of binary polymer blends. (c) 2008 American Institute of Physics.