A new self-plasticizing aliphatic polycarbonate comprising flexible alkyl and alkyl ether side groups was
designed and synthesized from six-membered cyclic carbonate monomers with the aim of producing a
material with high molecular flexibility (low Tg) and concomitant high ionic conductivity when used as a
polymer electrolyte. The Tg of the novel polycarbonate was determined to be 49.4 C at a molecular
weight of 34 400 g mol1
, which is the lowest reported Tg to date for a substituted poly(trimethylene
carbonate). UV-crosslinked polymer electrolytes were produced based on this novel material together
with LiTFSI salt and showed ionic conductivities in the range of 2 108 to 2 107 S cm1 at room
temperature and 1 106 to 1 105 S cm1 at 100 C. The limited ionic conductivities of these
electrolytes indicate that high molecular flexibility alone does not guarantee fast ion transport in solid
polymer electrolytes and that other factors, such as the polarity of the polymer host material, will also
influence the transport properties of the electrolyte.