Fabrication of fluorinated raspberry particles and their use as building blocks for the construction of superhydrophobic films to mimic the wettabilities from lotus leaves to rose petals

Abstract

Reported herein is the preparation of poly((glycidyl methacrylate)-co-(ethylene glycol dimethacrylate)) raspberry-like colloidal particles (also denoted as RPs) bearing micro-/nano-scale surface roughness and the fabrication of superhydrophobic films with tunable adhesion derived from the RPs after their fluorination. The RPs were prepared via the one-pot dispersion polymerization of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA). The size and the surface roughness of the RPs can be readily tuned by adjusting the polymerization parameters, including the temperature, the feed monomer mole ratio, the initiator concentration, and so on. A possible mechanism of the formation of RPs was proposed according to the morphological evolution observed during the polymerization process as monitored via transmission electron microscopy (TEM), scanning electron microscopy (SEM), and size variation as evaluated with dynamic light scattering (DLS) measurements. Fluorinated RPs (also denoted as FRPs) with various fluorination degrees were further prepared by reaction between the epoxy groups of the RPs and the thiol group of perfluorodecanethiol (PFDT). The raspberry-like morphology of the FRPs was maintained as confirmed via SEM observation. By only changing the surface chemistry rather than the roughness, superhydrophobic films with tunable superhydrophobic properties capable of mimicking wettabilities ranging from those of lotus leaves to those of rose petals were easily prepared by drop-casting dispersions of FRPs onto glass substrates.