Study on the surface morphology and wettability of nanocomposite films based on poly(methyl methacrylate) containing polyhedral oligomeric silsesquioxane/silica nanohybrids

Superhydrophobic behavior was imparted on the surface of poly(methyl methacrylate) (PMMA) films using a hybrid of nanoparticles including polyhedral oligomeric silsesquioxane (POSS) and silica. To this end, an improved phase separation method based on the concurrent use of nonsolvent and nanoparticles was used. In the absence of nanoparticles, scanning electron microscopy (SEM) results revealed the surface segregation of PMMA macromolecules as the ethanol content was increased causing the roughness to be enhanced; however, no superhydrophobic property was attained. SEM and X-ray photoelectron spectroscopy results demonstrated that POSS particles were be mainly localized at the bulk of the nanocomposite films, and thus, superhydrophobicity could not be achieved. Accordingly, hydrophobic silica nanoparticles were introduced to the formulation leading to the superhydrophobic behavior. The durability of the superhydrophobic samples was investigated by immersing the films into the solutions with different pH values under dynamic conditions. Despite its more initial hydrophobicity, the sample made via the concurrent use of nonsolvent and nanohybrid exhibited a poorer durability, which was attributed to the more porous structure and formation of large cracks at the surface layer of the films. The results of this study could be used as a hint of nanohybrids' efficiency in the fabrication of stable superhydrophobic surfaces. POLYM. COMPOS., 40:E127-E135, 2019. (c) 2017 Society of Plastics Engineers