Intellectual Merit: We have employed the new technique of x-ray photon correlation spectroscopy

1. Structure and Dynamics of Polymeric Complex FluidsS. G. J. Mochrie, Yale University, DMR-0453856 Intellectual Merit: We have employed the new technique of x-ray photon correlation spectroscopy (XPCS) to characterize the dynamics of a polymer- based sponge phase, shown right in an electron microscopy image . The sponge phase consists of a randomly-connected, self-assembled membrane, composed of triblock copolymer surrounded by homopolymer. Our XPCS experiments test recent theoretical predictions concerning the dynamics of the sponge phase, but, at lower temperatures reveal unusual compressed-exponential dynamics (right), suggesting that this system realizes a “jammed” state, of a sort that has also attracted considerable interest recently. This is the first time that a fluid-to-jammed transition has been observed to occur as a function of temperature. Physical Review Letters 97, 066102 (2006)

2. Structure and Dynamics of Polymeric Complex Fluids S. G. J. Mochrie, Yale University, DMR-0453856 Broad Impact: Activities under DMR-04533856 are: (1) leading to further improvements in XPCS capabilities, thus encouraging, and enabling other scientists to pursue their own XPCS research, further growing the worldwide XPCS user community. For example, shown right is dynamic x-ray scattering data -- the basis of the XPCS technique -- captured at 500 images per second, faster than previously possible (and replayed at 25 fps); and (2) informing key decisions about the next generation of x-ray facilities, currently in the planning, proposal, design, and construction stages, including LCLS at Stanford, NSLS II at BNL, the APS Upgrade at ANL, the ERL at Cornell, and new facilities in Germany, the UK, and elsewhere. Right is the APS.