Dynamics of complexes of poly(N-vinylpyrrolidone)-C60 in aqueous solution

Hydration of complexes of poly(N-vinylpyrrolidone) (PVP) with C-60 has been studied by SANS and NSE to elucidate their self-assembly induced by small amounts of fullerene (similar to 10(-6) wt%) in solution. As compared to PVP in D2O, the complexes (C-60 vertical bar 8 PVP), forming fractal structures, displayed specific molecular dynamics in the time range t = 0.2-20 ns at momentum transfer q similar to 0.3-0.6 nm(-1) comparable with inverse PVP segmental size. By heating up to 80 degrees C the complexes became locally ordered that leads to their oscillating dynamics (soft mode: h Omega similar to 200 neV at q similar to 0.27 nm(-1)). (C) 2004 Elsevier B.V. All rights reserved.