“Machine-experimental” study of separate chain conformations in polymer concentrates

Abstract

The Monte Carlo method has been used to examine the equilibrium characteristics of flexible chain concentrations in model lattices. Considered were the specific volume of the chain units and the reactions of random ones coming close together. The concentration effects have been considered by dividing all of the space into cubes of edges l = 5−21 long in which the periodic limiting conditions permit the formation of n chains composed of N = 16−121 units each. The studied concentration range was c= nN/ l 3, which varied from zero to c ≅0·7. The existence of forces of repulsion between chain units (a good solvent has been found to give rise to a mean square radius of inertia and number of intermolecular contacts in each of the chains which approached those for a separate chain in a θ solvent as the concentration increased). The same effect also applies to forces of attraction between chain units. In the concentration range c⩾ c k, in which the intramolecular chain characteristics almost cease to change, there is overlapping of macromolecular coils when c k ∼[ ν] θ −1, in which [ ν] θ −intrinsic viscosity of the dilute θ solution. For the inter-chain unit energy of reaction at the θ point there is no concentration dependence of the geometrical and thermodynamic characteristics of separate macromolecules.