Conduction mechanism in polymeric membranes based on PEO or PVdF-HFP and containing a piperidinium ionic liquid

• Two types of polymer electrolyte membranes were prepared using poly(ethylene oxide) (PEO) and poly(vinylidene difluoride-co-hexafluoropropylene) (PVdF-HFP), with different amounts of the ionic liquid N-methyl-N-propylpiperidinium bis(trifluoromethane-sulfonyl) imide ([PP13][TFSI]) added. The results from differential scanning calorimetry and conductivity measurements show that in the case of PVdF-HFP membranes the glass transition temperature T-g decreases and the room temperature ionic conductivity increases with increasing content of the ionic liquid (up to 60 wt.%). However, in the case of PEO based membranes Tg is less significantly affected and the room temperature ionic conductivity increases only up to 30 wt.% of ionic liquid, beyond which a steady value of about 5.10(-5) S/cm is reached. The results from Raman spectroscopy show that the characteristic vibrational mode of the TFSI anion at similar to 742 cm(-1) is weakly affected in the membranes prepared from PVdF-HFP, whereas for those based on PEO it has a clearer composition dependence. These results suggest ion-ion and ion-polymer interactions of different nature, which together with the different nanomorphologies adopted by PEO and PVdF-HFP, as revealed by X-ray scattering, give rise to different composition dependences of the macroscopically measured ionic conductivity. (C) 2019 The Authors. Published by Elsevier Ltd.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Keramteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Ceramics (hsv//eng)

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

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

NATURVETENSKAP  -- Fysik -- Annan fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Other Physics Topics (hsv//eng)

Nyckelord

Ionic liquid and ionic conductivity

Poly(vinylidene difluoride-co-hexafluoropropylene)

Poly(ethylene oxide)

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