Interpenetrating polymer networks (IPNs) combining polybutadiene (PB) and poly(ethylene oxide) (PEO) show very close a relaxations leading to a partially resolved signal as determined by DMA. Nevertheless it is shown in this paper, in complement to part I, that it is still possible to get a better insight into the material morphology through two different approaches. First DMA experimental data are compared with theoretical predictions obtained from mechanical coupling models (Christensen and Lo and Budiansky approaches). Second, it is shown that full splitting of DMA signals can be induced providing that LiClO4 is introduced in polybutadiene/poly(ethylene oxide) IPNs. Indeed the Li+ cation has a particular affinity for the ethylene oxide segments in the PEO network. IPN morphologies are then discussed much more accurately according to LiClO4 loaded IPN mechanical behaviour. This concept could be usefully generalized to other types of polymers IPN associations as long as a selective complexation agent for one of the partner networks can be found that selectively modifies one particular property of this partner network.