Tuning the glass transition of siloxane-based poly(ionic liquid)s towards high ion conductivity

• Herein, we report a simple and versatile synthetic approach towards siloxane-based poly(ionic liquid)s (PILs) with unusually low glass transition temperatures (Tg) down to −73°C, and thus “liquid-like” behavior at room temperature. We designed a polydimethylsiloxane-derived copolymer carrying dialkylimidazolium moieties, and by careful selection of the side-chain length and the type of anions we were able to manipulate its Tg over a wide range and reach high ionic conductivities (σDC) up to 4.8 × 10−5 S/cm at 300 K. The ionized species make up only a minor fraction (<25 mol%) of the overall repeating units and are supposedly randomly distributed: Yet our results indicate dramatic effects on the thermal properties due to repulsive interactions between ionic and non-ionic segments.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

conductivity

glass transition temperature

poly(ionic liquid)

polysiloxane

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