| Polymerized ionic liquids (PILs) realise immobilization of the ionic liquids, andprossess the unique properties of ionic liquids and macromolecular architecture,whose conductivity, catalytic activity and thermostability are improved dramatically.As green environmentally-friendly materials, PILs have wide applications forbatteries, supercapacitors, catalysis and other fields.In this work, a series of imidazolium-type ionic liquid polymers with differentmolecular weights and anions were prepared by combining free radicalpolymerization and ion exchange. They were characterized by fourier transforminfrared (FT-IR), nuclear magnetic resonance (NMR), electron spray ionization massspectrometry (ESI-MS) and thermogravimetric analysis (TGA). The effect ofpolymerization temperature and initiator dosage on their molecular weights wasinvestigated. The Knoevenagel condensation using benzaldehyde and ethylcyanoacetate as substrates was investigated to study the ralationship between thestucture of basic ionic liquid polymers and their catalytic performance. Moreover, theelectrochemical properties of various ionic liquid polymers-based electrolytes wereinvestigated.Firstly, imidazolium-type ionic liquid polymers (P[VBPIm]Cl) were synthesizedby free radical polymerization with N-(vinylbenzyl)-N’-propyl imidazolium chlorideionic liquid ([VBPIm]Cl) as raw meterials and azodiisobutyronitrile (AIBN) asinitiator. The results indicated that the molecular weight of P[VBPIm]Clincreased firstly and reached the maximum values at70oC, then decreased with theincrease of the polymerizatiion temperature. In addition, its molecular weightdesreased sharply firstly and then became contant as the amount of initiator increased.[VBPIm]Cl possessed a high thermal stability and its thermaldecomposition temperature was245oC.Secondly, basic ionic liquid polymers (BP[VBPIm]) were prepared by ionexchange and used as the catalysts in the Knoevenagel condensation withbenzaldehyde and ethyl cyanoacetate as substrates. The results showed thatBP[VBPIm] had excellent surface activity, which increased with increasing the molecule weight of BP[VBPIm] and P[VBPIm]Im had a higher catalytic activity thanthe ionic liquid with a similar structure to that of the monomer [VBPIm]Cl. Themolecule weight and anion species of BP[VBPIm] had great effect on the catalyticactivity. The lower molecular weight and strongly basic anion could improve catalyticactivity of BP[VBPIm] obviously, which was best in dimethyl sulfoxide. TheP[VBPIm]Im had a good catalytic activity to aromatic aldehydes or aliphatic ketoneswith active methylene compounds. Moreover, P[VBPIm]Im was easily recovered inthe system using benzaldehyde and malononitrile as substrates. However, the partlydeactivation of catalyst in the recycle lead to a significant deterioration ofcatalyst performances.Finally, polymerized ionic liquid iodide (P[VBPIm]I) were synthesized by ionexchange and P[VBPIm]I-based polymer/ionic liquid composite electrolytes wereprepared and applied to dye-sensitized dolar cells (DSSC). The results showed thatthe conversion efficiency and short circuit current increased firstly and then decreasedwith the increase of P[VBPIm]I loading. However, the maximum values were lowerthan that of ionic liquid-based electrolyte. The reliability of DSSC was enhanced withthe the loading of P[VBPIm]I. |
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