The interaction between sodium dodecyl sulfate (SDS) and polyvinylpyrrolidone (PVP) was investigated by using dynamic light scattering (DLS) and electron spin resonance (ESR). DLS results indicated that the hydrodynamic radius (R) of SDS micelles was R 61 nm, and PVP molecules crimped into coils with R 12 nm. The critical micelle concentration (cmc) of SDS determined by DLS and ESR is 6.4×10^-3 and 6.8×10^-3 mol·L^-1, respectively. PVP molecules strongly interact with SDS which are wrapped around the SDS micelles, shielding hydrocarbon groups on the surface of the micelle from contact with water. The change of the hyperfine splitting constant (A_N) and the correlation time (τ_c) from the spin-probe, 5-doxyl stearic acid, revealed that the polar and the high microviscosity in SDS micelles and PVP-SDS complex aggregates are lower than those in solvent. The microviscosity of PVP-SDS aggregates is higher than that of SDS micelles.

Key words: interaction, sodium dodecyl sulfate(SDS), polyvinylpyrrolidone(PVP), laser light scattering, electron spin resonance