Flexible polymers in bulk

On increasing the concentration of a polymer in solution, different chains begin to collide with each other, and as the concentration increases further and the frequency of collisions rises, the chain mobility becomes dramatically restricted. The situation of a chain in a mesh of more or less 

At the same time, the segment rotational motions also become severely limited. Steric collisions of the chain with the neighbours cause, at first, departure of the segment orientation correlation function from a single exponential decay function characteristic of a free chain, and on further increase of concentration the segment dynamics change completely. 

When studying the molecular dynamics of a polymer chain in a concentrated solution or in bulk material, both the intra- and inter-molecular interactions have to be considered, and the correlation function Ti t), as well as the autocorrelation term, should account for 

The general properties of a, jS- and aj8-processes have been extensively studied over a wide range of temperature, frequency and pressure, and 

The intramolecular motions which relax the total dielectric increment, As = So — b oo, or in other words the mean square dipole moment m , can generally be divided into two classes (i) fast local motions and (ii) large-scale, slower Brownian motions of chains. The former are responsible for the jS-process, and the latter for the a-process. The mean square dipole moment, = l m/(0)m/k(0) , where the sum is taken over 

---