Poly(phosphazene-ethylene oxide) di- and triblock copolymers as solid polymer electrolytes

The synthesis of polyphosphazene-co-poly(ethylene oxide) block copolymers w ith well-defined molecular weights has been accomplished via end-functional ized polymer intermediates. Mono- and diamine-terminated poly(ethylene oxid es) (PEO = (CH2CH2O)(n)-CH2CH2-) were used to produce polymerbased phosphor animines, CH3O-(CH2CH2O)(n)-CH2CH2-NH(CF3CH2O)(2)P=NSiMe3 and Me3SiN=P(OCH2 -CF3)NH-(CH2CH2O)(n)-CH2CH2-NH(CF3CH2O)(2)P NSiMe3. These were then convert ed to macroinitiators via reaction with PCl5 to produce CH3O-PEO-NH[(CF3CH2 O)(2)P=NPCl3](+)[PCl6](-) and [Cl3PN=P(OCH2-CF3)NH-PEO-NH[(CF3CH2O)(2)P=NPC l3](2+) [PCl6](2)(-), respectively. These macroinitiators were used to poly merize Cl3P=NSiMe3 in a living manner to produce diblock copolymers of poly phosphazenes with poly(ethylene oxide) or triblock copolymers with poly(eth ylene oxide) blocks flanked by polyphosphazene components. In addition, the monophosphoranimine-terminated PEO was employed as a terminator in the liv ing, cationic polymerization of Cl3P=NSiMe3 to produce triblock copolymers with a polyphosphazene block flanked by two poly(ethylene oxide) blocks. Po lymers for use as solid-ionic conduction media or hydrogels were produced b y nucleophilic replacement of the chlorine atoms along the polyphosphazene segments by methoxyethoxyethoxy units. The ionic conductivities of these ma terials, after complexation with varying ratios of lithium triflate, ranged from 7.6 x 10(-6) to 1.0 x 10(-4) S cm(-1) for a temperature range of 20 - 80 degreesC.