Aggregation, TCNQ salt-polymer

Under the condition of donor exchange reaction, it is unlikely to form an orderly packedohomogeneons stack of TCNQ salt crystals, as in the case of TCNQ binding to the polymers through CT interaction, thongh the molecules can form a larger aggregate. 

NMP TCNQ concentration plot (Fig. 7), it appears that there exist three stages of equilibria in the salt aggregation in the polymer matrix a loose ion-pairing, a tight ion-pairing, and an aggregation ... 

The association behavior of NMP+TCNQ was explored by visible spectra to look into the microcrystallization of the salt under the influence of matrix polymers. As in the solutions, for dimers and higher molecular aggregates to form in polymers, the salt concentrations must exceed a certain level at which a constant amount of free volume within the polymer matrix is fully occupied. In this case, matrix polymers act as solvents whose dielectric constant and complexing power (donor strength) + ... 

Such a matrix effect on the salt aggregation is reflected on the film morphology (Fig. 6) of the NMP TCNQ/ TCNQ polymer system in P(BA), PMMA and PC, microcrystallization of the salt is well developed, while in P(ECZA) and P(NA), the salt crystallization is imperfect, resulting in poor conductivity. 

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