Excluded Volume Effect and Light Scattering of Chain Polymers

The light scattering by chain polymers with excluded volume effect is calculated approximately, by assuming the same expansion coefficients of polymer subchains with those used in the previous excluded volume theory. The scattering function obtained which represents the angular distribution of scattered light intensity is a decreasing function of the molecular expansion coefficient α. This function contains an adjustable parameter µ 0 which determines the expansion coefficient of adjacent segments-distance. When this is put as µ 0 =2, the scattering function coincides with that of Debye, and Zinm and others for uniformly expanded random coil chain, and in the other extreme case where µ 0 =0, the result is qualitatively equivalent to the previous calculation for non uniformly expanded random coil. Also when the value µ 0 =4/3∼3/2 which is obtained from the excluded volume theory is substituted, the result is closer to former one for uniformly expanded random coil.