基于变压红外光谱研究离子液体[MPIM][I]与石墨烯氧化物之间的相互作用

本研究利用红外光谱研究不同压力下离子液体1-Methy1-3-propylimidazolium iodide(MPIM]I])与石墨烯及其氧化物的相互作用.结果表明,MPIM]I]对压力的变化具有高敏感度,咪唑环与烷基链在0.4 GPa时产生相变化,可明显观察到吸收峰的裂解,且连续加压会导致咪唑环与烷基链的振动频率蓝移.MPIM]I]与石墨烯作用时加压至2.5 GPa也未观测到相变化的产生,且咪唑环与烷基链的振动频率蓝移趋势也不明显;MPIM]I]与石墨烯氧化物作用时咪唑环与烷基链的结果与添加石墨烯时几乎相同.石墨烯氧化物具有羟基、羧基、环氧基等共价键结在其表面,这些羟基会扰动MPIM]I]中的咪唑环与烷基链,导致在常压下振动频率发生蓝移,进而表明石墨烯表面的官能基团会与离子液体产生相互作用.

Study of interaction between graphene oxide and ionic liquid [MPIM][I] based on infrared spectroscopy with variable pressure

The interaction between grapheme or graphene oxide and ionic liquid 1-Methy1-3-propylimidazolium iodide (MPIM]I]) is studied by use of infrared spectroscopy at different pressures. The results show that MPIM]I] is highly sensitive to the pressure variation and the phase changes of imidazole ring and alkyl chain are produced at 0.4 GPa. The decomposition of absorption peaks can be clearly observed and the vibration frequency blue shifts of imidazole ring and alkyl chain can be also generated duo to compression continuously. The phase changes are not observed at pressure reached to 2.5 GPa for MPIM]I] mixed with grapheme and the vibration frequency blue shifts of imidazole ring and alkyl chain are also not significant. The results of imidazole ring and alkyl chain for MPIM]I] mixed with grapheme oxide are almost identical to that for MPIM]I] mixed with grapheme. The imidazole rings and alkyl chains of MPIM]I] are perturbed by the covalent bonds of hydroxy, carboxy and epoxy existed on the surface of graphene oxide, and it leads to the blue shift production of vibration frequency at atmospheric pressure. This result suggests that the interaction between ionic liquids and functional groups can be caused.