Abstract: | The depolarized forward-scattered light from solutions of rat tail collagen has been studied by photon correlation spectroscopy. The measured autocorrelation function is seen to decay on two widely different time scales. The decay time for the fast component is consistent with the rotational diffusion of rodlike collagen monomers. The slowly decaying autocorrelation component is attributed to large nonspecific aggregates of collagen. A substantial fraction of the collagen is in this aggregated form. Extrapolation of the faster decay times to zero concentration yields a value of θ = 1082 ± 30 sec?1 for the rotational diffusion coefficient of the collagen monomer. |