Highly ordered luminescent microporous films prepared from crystalline conjugated rod-coil diblock copolymers of PF-b-PSA and their superhydrophobic characteristics

Abstract

We have successfully prepared three crystalline conjugated rod–coil diblock copolymers of poly[2,7-(9,9-dihexylfluorene)]-block-poly(stearyl acrylate) (PF-b-PSA), PF₇-b-PSA₆₄, PF₇-b-PSA₉₃, and PF₇-b-PSA₁₆₆, via the combination of a Suzuki coupling reaction and atom transfer radical polymerization. The crystalline comb-like PSA coil segment effectively formed the highly ordered microporous films through a “breath figure” (BF) process. On the other hand, the blue-emission band of the PF block was blue-shifting and became narrower as the PSA block was increased. The effects of block ratio, humidity, and solution concentrations on the porous structures were studied. The longer PSA block length, larger humidity, and higher copolymer concentration formed a more regular PF-b-PSA microporous structure. The images of SEM and scanning laser confocal microscope of the PF₇-b-PSA₁₆₆ microporous film showed that all bubbles were independent and perfectly monodisperse with a pore diameter ca. 1.85 μm. Furthermore, a rod-co-valley-like structure exhibited superhydrophobicity (contact angle up to 163 ± 0.3°), which was obtained from the peeled skin layer of the ordered PF₇-b-PSA₁₆₆ microporous surface. The experimental results revealed that multifunctional ordered microporous films could be successfully prepared from crystalline conjugated rod–coil block copolymers.