Skip to Main Content
Your organization might have access to this article on the publisher's site. To check, click on this link:http://dx.doi.org/+10.1063/1.349777
This paper deals with two major problems often encountered in analyzing the measured autocorrelation functions in photon correlation spectroscopy of semidilute polymer solutions and gels: partial heterodyning and the interpretation of slow relaxation modes. These topics are discussed in the context of measurements of semidilute aqueous polyacrylamide solutions and gels used as electrophoresis media. Following a review of basic principles of Rayleigh light scattering and photon correlation spectroscopy, data analysis procedures, including the constrained Laplace inversion program contin, are first re‐examined by presenting the results from aqueous latex standard solutions. The method to analyze the partial heterodyne autocorrelation function is then presented and tested against the simulated partial heterodyne autocorrelation functions. Finally, the recently observed slow relaxation modes in polyacrylamide solutions are examined in detail with a test of contin against the simulated autocorrelation functions consisting of a trimodal distribution of relaxation rates. The results confirm that the slow relaxation modes detected in polyacrylamide solutions are indeed physical modes originating from structural relaxation and interdiffusion.