Poly[(oligoethylene glycol) dihydroxytitanate] as organic-inorganic polymer-electrolytes

Two new poly[(oligoethylene glycol) dihydroxytitanate] electrolytic systems were prepared by a polycondensation reaction between: Ti(OEt)4 and polyethylene glycol 400 (PEG 400) (I), and Ti(OEt)4 and PEG 400/LiCl complex (II). The polymers thus obtained show a solid rubbery consistency and are very stable under inert atmosphere. The structure, morphology and conductivity of these materials were investigated. On the basis of analytical data and vibrational studies it was concluded that polymers (I) and (II) are inorganic-organic materials with titanium atoms bonded together by PEG bridges. Particularly, inter-chain interactions in polymer (I) occur by means of hydrogen bonds between titanium hydroxyl groups and ethereal oxygens of PEG chains, while polymer (II) contains both titanium-PEG interactions and a second type of inter-chain interaction due to the presence of hydrogen bonding clusters around Cl- ions. Scanning electron microscopy (SEM) revealed two types of morphologies in polymers (I) and (II). Conductivity measurements made at different temperatures indicated that both polymers conduct ionically. Two conductivity mechanisms are present in these materials, which are strongly influenced by segmental motions of the polymer chains. At 25 degrees C polymers (I) and (II) showed conductivities of ca. 3 x 10-6 and 4 x 10-6 S/cm-1 respectively.