Rheological characterization for the gelation process of polyaniline-emeraldine base/NMP solution by oscillatory test

The gelation process of the 4 wt.(percent)PAni-EB/NMP solution was characterized by measuring the viscoelastic property in oscillatory test. The solution showed a weak gel state in which the storage modulus decreased rapidly even at low strain in the constant angular frequency test, and the damping factor increased rapidly to a state of typical viscous liquid at a specific angular frequency in the early stage of the constant strain test. It was supposed that the weak bonding of dipole force between polymer molecules was broken by the external deformation. The angular frequency of the sudden change in the damping factor was defined as a critical angular frequency. The PAni solutions with a prior shear deformation resulted in the lower critical angular frequency, showing the delay of gelation process by the prior shear deformation. The PAni solution with the metal-organic framework(MOF)resulted in the lower critical angular frequency proving the antigel effect of the MOF.