Intermediate range structural correlations in polymer electrolyte PPO-LiClO4 from neutron diffraction experiments and reverse Monte Carlo simulations

An amorphous polymer electrolyte, PPO-LiClO4, has for the first time been studied using neutron diffraction technique. For comparison pure poly(propylene oxide) (PPO) and deuterated PPO samples have been investigated. Large changes of the static structure factor S(Q) are observed in the low-e range as the salt is introduced in the polymer matrix. From computer modelling of PPO using the Reverse Monte Carlo technique the observations are attributed to changes of interchain correlations. The peak in the static structure factor related to intermediate range ordering is found to be more narrow and located at a larger e-value in the polymer-salt complexes compared;to the single peak of the pure polymer. The findings can be explained by the fact that the solvated ions induce chain contraction and ordering. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.