Configurational partition functions and entropies for polyoxide chains having the repeat unit

Rotational isomeric state theory is used to calculate values of the configurational partition function z and entropy S for polyoxide chains having the repeat unit [(CH 2),.-O-1. The values of z are at least qualitatively useful in interpreting the effect of the number y of methylene groups in the repeat unit on the characteristic ratio < r 2)01 n 12 of the unperturbed dimensions relative to the number of skeletal bonds and the average square of their lengths. For example. z has a maximum (corresponding to maximum "equilibrium flexibility" of the chain) at y = 3, where < r 2)01 n 12 is at a minimum. The configurational entropy S, however, shows a very poor correlation with either z or <r2)0 In1 2 : similar difficulties have been noted in comparisons between some polypeptide chains, and between some polysaccharide chains.