Dynamic Light Scattering from Polymer Solutions: The Subtraction Technique

Correlation functions measured in dynamic light scattering on polymer solutions often contain a strong sharp decay which obscures and renders difficult a reliable analysis of other decay processes. We demonstrate that this problem can be circumvented by performing a two-step inverse Laplace transformation. The strong component obtained in the first step is subtracted from the correlation function which is then re-analyzed in the second step. We illustrate this technique on semidilute solutions of polystyrene in cyclohexane and tetrahydrofuran.