Precipitation and sol formation from poly(p-phenylene)s solutions by spectroscopic study

Abstract

By UV–vis absorption, photoluminescence, and FT-IR spectroscopies, the relationship between conformations and photophysical properties of hairy-rod poly(2,5-dioctyloxy-p-phenylene)s in dilute solution was investigated in the good solvent, the poor solvent and the mixed good and poor solvents. The solvent quality such as polarity, aromaticity and solubility parameter can govern the conjugation length such as the extended, twist and shrinking conformations. By the addition of the polar poor solvent, the polymeric aggregates can be induced to form the colloidal particles and precipitate. In addition, the nonpolar poor solvent can interact with the flexible alkane side chains to form the three-dimensional networks. Further supports on the conjugated polymer aggregations can also be given by XRD and SEM techniques. Therefore, by changing the species and the proportion of the mixed solvents, the polymer aggregation structure can be controllable to prepare the conjugated polymeric supermacromolecular architectures.