Novel fluoroalkyl polyhedral oligomeric silsesquioxane (FPOSS) macromers for fabricating diblock copolymer as self-cleaning coatings

Abstract

Novel diblock copolymer PMMA-b-P(MA-FPOSS) was synthesized by ethyl bromoisobutyrate initiating methyl methacrylate (MMA) and macromer methacrylate fluoroalkyl polyhedral oligomeric silsesquioxane (MA-FPOSS), which demonstrated excellent wettability for hydrophobic coatings. The macromer MA-FPOSS was synthesized via the corner-capping reaction with designed structure. The polymerization kinetics of MA-FPOSS indicated the living atom transfer radical polymerization (ATRP) with 75 % conversion. Self-assembled behavior demonstrated core/shell micelles (100−200 nm) of PMMA-b-P(MA-FPOSS) in solutions with P(MA-FPOSS)-core and PMMA-shell: the biggest micelles with lowest content formed in dimethyl carbonate (DMC) and the smallest one with highest content in chloroform (CHCl3). The surface of the PMMA-b-P(MA-FPOSS) film from CHCl3 exhibited the highest roughness (Ra = 6.1 nm) and the highest fluoride content (35.17 %), yielding the highest water contact angles (Static CA = 115.0 ± 1.3°). Whereas, the DMC-casted film exhibited the lowest roughness (Ra = 1.4 nm), the lowest fluoride content (31.69 %) and lowest water contact angles (Static CA = 113.5 ± 2.0°). The PMMA-b-P(MA-FPOSS) coated on the cotton fabric, sandstones and filter papers revealed the super- or high-hydrophobicity (＞150°), excellent chemical and mechanical stabilities, as well as self-cleaning property. Herein, such coatings of FPOSS-based copolymers render promising hydrophobic and self-cleaning applications in the future.