Surface-Initiated Polymer/Ionic Liquid Gel Films

We report the preparation of polymer/ionic liquid (IL) gels by incorporating ILs into surface-initiated poly(dicyclopentadiene) (pDCPD) films using a simple immersion method. In the method, a surface-initiated pDCPD film was exposed to a solution of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6]) in dichloromethane, which led to incorporation of the IL within the film. The volume ratio of the incorporated [bmim] [PF6] to the original pDCPD film was adjusted as high as 0.5, and it is strongly dependent on the solvent, IL solution concentration, and the sample immersion time. The maximum IL loading is affected by the swellability of pDCPD films in the solvent, the solubility of the IL in the solvent, and interactions between the IL and the polymer. The method is also proven to be feasible in preparing pDCPD-IL gels with different IL species. The incorporated ILs dramatically change the properties of the pDCPD films. The pDCPD-IL gel film has a higher shear loss modulus than that of the pure pDCPD film based on quartz crystal microbalance with dissipation. The resistance of the film against ion transfer is at least 4 orders of magnitude lower at high levels of IL incorporation than the resistance of pure pDCPD.