Abstract
In order to design more effective solid polymer electrolytes, it is important to decouple ion conductivity
from polymer segmental motion. To that end, novel polymers based on oxanorbornene dicarboximide
monomers with varying lengths of oligomeric ethylene oxide side chains have been synthesized using
ring opening metathesis polymerization. These unique polymers have a fairly rigid and bulky backbone
and were used to investigate the decoupling of ion motion from polymer segmental dynamics. Ion
conductivity was measured using broadband dielectric spectroscopy for varying levels of added lithium
salt. The conductivity data demonstrate six to seven orders of separation in timescale of ion conductivity
from polymer segmental motion for polymers with shorter ethylene oxide side chains. However,
commensurate changes in the glass transition temperatures Tg reduce the effect of decoupling in ion
conductivity and lead to lower conductivity at ambient conditions. These results suggest that both an
increase in decoupling and a reduction in Tg might be required to develop solid polymer electrolytes with
high ion conductivity at room temperature.
