Über die Gestalt von Fadenmolekülen in Lösung

Summary

Some arguments put forward byG. Bier in a recent article in order to supportH. Staudinger's assumption that chain molecules in solution should behave like straight rigid rods are examined. It is shown that the assumptions made byG. Bier are largely arbitrary. The main argument is the assumption that the C-C-bond in long chain molecules should not show any rotation. As far as this point is concerned, attention is drawn to some recent publications showing that the viscosity of shape of chain molecules can be determined by experiment (specific viscosity and double refraction of flow at high velocity gradients). According to these determinations the time necessary for a complete change of shape, using partially free rotation, is of the order of 10⁻⁵–10⁻³ seconds for molecules like nitrocellulose or polystyrene up to degrees of polymerization of several thousands and for viscosities of the solvent of the order of 10⁻² poises.