Composition fluctuations, light scattering and diffusion

With mixtures of two polymer homologues (wi = 0.5) with LML (P1+P2+LML) (pu, = 1,000, ifi = 10 , Pw/Pn to vary) as an example, mathematical analysis (Shchyogolev, 1983) has shown a substantial fall in the component Pj solubility (the smaller p) in the ternary P1+P2+LML mixture as compared with the binary P2+LML one, which is in agreement with a more rigorous (but a more bulky as well) theoretical analysis and experiment (Cornet, 1968). 

---

Tn the critical region of mixtures of two or more components some physical properties such as light scattering, ultrasonic absorption, heat capacity, and viscosity show anomalous behavior. At the critical concentration of a binary system the sound absorption (13, 26), dissymmetry ratio of scattered light (2, 4-7, II, 12, 23), temperature coefficient of the viscosity (8,14,15,18), and the heat capacity (15) show a maximum at the critical temperature, whereas the diffusion coefficient (27, 28) tends to a minimum. Starting from the fluctuation theory and the basic considerations of Omstein and Zemike (25), Debye (3) made the assumption that near the critical point, the work which is necessary to establish a composition fluctuation depends not only on the average square of the amplitude but also on the average square of the local... 

Evanescent wave dynamic light scattering (EWDLS) can be used to study the rapid motion of submicron particles near and on interfaces. Two situations have been studied restricted diffusion of spherical particles moving near an interface, and composition fluctuations of polymers attached to the interface. 

---