电纺聚砜咪唑膜的分子动力学与DFT计算研究

Molecular dynamics simulation and DFT calculation for electrospinning process of imidazole-functionalized polysulfone AEMs

采用分子动力学模拟和密度泛函理论(DFT),通过径向分布函数、弱相互作用以及能量分析,提出静电纺丝静电场作用下聚砜咪唑(ImPSf)的二甲基甲酰胺(DMF)溶液成膜过程中离子簇的形成机制.与浇铸条件下Cl-桥联咪唑功能基团不同,在电纺条件下,DMF偶极矩增大,DMF与咪唑功能基团的氢键作用增强,DMF挥发时带动功能基团向相界面运动,倾向于在纤维表面聚集形成离子通道.静电场作用还可以打破咪唑功能基团与聚砜主链之间的ππ堆叠吸引作用,从而促进功能基团形成微观相分离,提高膜的电导率.

Molecular dynamics simulation and density functional theory(DFT)calculations are used to study the interaction between the components in the imidazole-functionalized polysulfone(ImPSf)-dimethylformamide(DMF)solution.Through analysis of the radial distribution function between different molecules,weak interactions and energy of hydrogen bonds,mechanism for the formation of ion clusters during the process of electrospinning are proposed.In casting conditions,chlorides are used as intermediates to connect the imidazole functional groups of different chains.Under electrospinning conditions,the effect of DMF and imidazole functional groups is enhanced,so DMF drives the functional groups toward the interface and imidazoles gather outside the fiber to form ion channels.For ImPSf-DMF solution,there is aππconjugated attraction between imidazole and polysulfone main chain.Under electrospinning conditions,functional groups are separated from the main chains under the action of DMF and electric field,thereby promoting microscopic phase separation and forming ion channels,which will improve the ion conductivity of membrane.