Using iron sulphate as oxidant

poly(3

4-ethylenedioxythiophene) (PEDOT) was prepared by chemical oxidation method under the condition of pH=2.The dispersion of PEDOT in nine different organic solvents was studied.N-methyl pyrrolidone displayed the best dispersibility for the polymer; after standing for 3 weeks

the dispersion system still retained a high concentration of 1.35 mg/mL.The density of the polymer was calculated by means of pycnometer method.According to group contribution method

the solubility parameters of the polymer were obtained.The dipole moment of polymer was also calculated with the assistance of the simulation of Chem 3D.Importantly

the solubility parameter and dipole moment were concluded to be two major factors affecting the dispersibility of the polymer in organic solvent.In other words

when both the solubility parameter and the dipole moment of PEDOT are simultaneously close to those of the solvent

the polymer will display good dispersibility in this solvent.Although the dipole moments of solvent NMP (13.6410-3 Cm) and DMSO (13.3410-3 Cm) are all very close to that of PEDOT (14.5810-3 Cm)

the solubility parameter of solvent NMP (22.94 J0.5 cm-1.5) is more close to that of polymer PEDOT (21.28 J0.5 cm-1.5).From the viewpoint of the solubility parameter component

compared to DMSO (19.03 J0.5 cm-1.5)

the solvent of NMP (18.03 J0.5 cm-1.5) has closer dispersion solubility parameter component to the polymer (16.39 J0.5 cm-1.5).Additionally

the observed Tyndall phenomenon suggests the colloidal state of PEDOT in the organic solvents.The structure stability of polymer was further confirmed via infrared spectroscopy and scanning electron microscopy.