Polyhedral oligomeric silsesquioxanes tethered with perfluoroalkylthioether corner groups: Facile synthesis and enhancement of hydrophobicity of their polymer blends

Octa(vinyl)-POSS or octa(vinyldimethylsilyloxy)-POSS reacts with perfluoroalkyl thiol in the presence of 2,2′-azobisisobutyronitrile to afford perfluoroalkylthioether substituted POSS compounds in high yields. ²⁹Si NMR and MALDI-TOF mass spectroscopic analyses indicate that the eight perfluoroalkylthioether chains are attached to the POSS core structure. Studies on poly(methyl methacrylate) (PMMA) blends with 5 wt% fluorinated POSS (fluoroPOSS) reveal that the POSS molecules considerably enhance the hydrophobicity of polymer blend surfaces as evidenced by significant increases in water contact angles from 71° for pure PMMA to 114-124° for fluoroPOSS-blends, making this type of fluoroPOSS a promising new class of highly hydrophobic hybrid materials.