Polystyrene brushes/TiO2 nanoparticles prepared via SI-ATRP on polypropylene and its superhydrophobicity

Abstract

Surface initiated-atom transfer radical polymerization (SI-ATRP) is a powerful tool for careful control of the materials surface properties, such as their wettability. In this study, superhydrophobic self-cleaning propylene (PP) surfaces were obtained by dipping the PP sticks into xylene at 125 °C containing dispersed hybrid core-brush TiO2 nanoparticles (NPs). The TiO2 NPs were functionalized with (3-chloropropyl) triethoxysilane (CLE) and they were employed for styrene grafting polymerization using CLE as an SI-ATRP initiator. DRIFT, TEM, SEM, WCA, optical profilometry, TGA and SAXS techniques were used for characterization. TEM images of the (NPs-CLEa)-g-PS revealed that the shell brush sizes were (10.4 ± 0.5) nm, (11.5 ± 0.5) nm and (18.8 ± 0.5) nm for a (CLE/xylene ratio), equal to 5/95, 10/90 and 20/80 respectively; indicating the dependence of the polymer grafting on the initiator ratio. The hierarchical micro-nanostructure generated on PP sticks, the WCA and hysteresis also depended on the a used. The WCA and hysteresis reached values of (161 ± 7)o and (3.7 ± 0.4)o, respectively for a = 20/80. The present methodology employs a simple and cost-effective technique to produce durable superhydrophobic surfaces on PP, offering the possibility to be used in different polymeric substrates. Additionally, it can be easily scale up and integrated into industrial processes.