Conjugated alternating copolymers containing cross-linkable 9,10-bis(hexyloxy)anthracene moieties were synthesized via Suzuki cross-coupling polymerization. Uncross-linked polymers fluoresced due to conjugation in the backbone from 9,10-dihexocyanthracene and comonomers of thiophene or fluorene. The anthracene-based homopolymers had a UV-vis absorbance at 320 nm and emission at 500 nm. Copolymers with thiphene shifted the absorbance to 255 nm, and the anthracene-fluorene copolymers had an absorbance of 360 nm. Upon irradiation, cross-linking in solution and in solid films was achieved through the [4+4] cycloaddition between anthracene units resulting in a loss of fluorescence for all samples due to the deconjugation of the backbone during cross-linking.
An investigation regarding the effect of water upon the MW of polyfuluorenes synthesized via Suzuki polycondensation was initiated. Polymers of high MW and low polydispersity were synthesized without the addition of water. Molecular weights in the range of 100,000 g/mol were easily obtained, and we postulate that the reason for this achievement is that removing the bulk aqueous phase from the reaction mixture leads to greater Mn polymers because CPs are inherently insoluble in water and the addition of water to the reaction mixtures in standard conditions could be a factor limiting their ability to achieve higher molecular weights.
