Static and dynamic light scattering of poly‐(α‐methyl styrene) in toluene in the dilute region

Abstract

Abstract The scattered intensity function S ( q, c ) and the intermediate scattering function S ( q, c , τ) of poly‐(α‐methyl styrene) ( M ω = 5.71 × 10 5 , 1.17 × 10 6 , and 2.96 × 10 6 ) in toluene in the dilute concentration region were measured as functions of concentration and scattering vector q . In infinitely dilute solution, the intensity function S ( q , 0) agrees well with the Debye function for u < 7, where u is ( qR g ) 2 . At finite concentration S ( q , c) varies from its thermodynamic value at low u to the single chain value at high u . Theoretical calculations of S ( q , c ) are in quantitative agreement with the observed scattering function in very dilute solutions. The intermediate scattering function S ( q, c , τ) is a single exponential decay with decay rate D m q 2 for u ≪ 1. For u > 1, S ( q, c , τ) is nonexponential, and when analyzed with a discrete inversion method, yields a bimodal distribution of decay rates. Both components are well represented as single exponential decays. D 0 can be obtained from the slower component. The decay rate of the faster component is a continuous function of u and approaches q 2 dependence at high u .