Preparation of stable spherical micelles with rigid backbones based on polyaryletherketone copolymers containing lateral pyridyl groups

A new bisphenol monomer, 3-(3,4-dihydroxyphenylimine) pyridine (PYPH), was synthesized via a deoxidization reaction of an amine. A series of novel polyaryletherketone copolymers containing lateral pyridyl groups (PY-PAEKs) based on PYPH, 2,2-di(4-hydroxyphenyl)propane and 4,4′-difluorobenzophenone were prepared by nucleophilic aromatic substitution polycondensation reactions. Furthermore, spherical micelles with rigid PY-PAEKs as the inner cores and flexible polyacrylic acid (PAA) as the outer shells were obtained in a selective solvent (H2O) successfully. The formation of the spherical micelles was confirmed by scanning electron and transmission electron microscopy as well as by surface tension measurements. The formation and size of the spherical micelles depended on the weight ratio of PAA/PY-PAEK, the concentration and pH value of the mixed solution containing the PY-PAEK and PAA, and the number of pyridyl groups in the PY-PAEK. The structure of the spherical micelles could be stabilized by a cross-linking reaction between the pyridyl groups of the PY-PAEKs and 1,4-dibromobutane. The diameter of the spherical micelles decreased because of the removal of the PAA shell from the PY-PAEK core after the cross-linking reaction. The resulting stable spherical micelles with rigid backbones did not dissolve in a number of polar solvents and remained unaffected by changes in the pH values.