Electrospinning of glass nanofibers to roughen a waterborne polyurethane coating toward smart applications

Polyurethane (PU) coating bulk was reinforced with electrospun glass nanofibers (GNF) and nanoparticles of lanthanide-doped strontium aluminate (NLSA) to produce mechanically reliable long-lasting photoluminescent and photochromic smart products. Transparent smart coatings of GNF@PU were prepared by the physical integration of lanthanide-doped strontium aluminate nanoparticles. The transparent appearance of GNF@PU was found to shift to green when exposed to ultraviolet light as proved by spectral examinations using photoluminescence and CIE Lab parameters. Fluorescence emission with instantaneous reversibility was monitored for GNF@PU hybrids with trace amounts of NLSA. Afterglow photoluminescence with slow reversibility was observed at higher phosphor concentrations in the GNF@PU hybrids. The coating hybrids revealed an emission band at 517 nm when excited at 365 nm. Transmission electron microscopic (TEM) analysis of the morphological properties of NLSA and GNF showed diameters of 8-12 nm and 75-250 nm, respectively. After being fabricated by electrospinning technique, GNF were incorporated into polyurethane coatings as a roughening agent. X-ray fluorescence (XRF), energy-dispersive X-ray (EDX), and scanning electron microscope (SEM) were used to investigate the morphological features of GNF and smart coatings of GNF@PU. Scratch resistance of smart coatings was found to be higher than that of NLSA-free polyurethane control sample. Both of hydrophobicity and UV resistance improved with an increase in NLSA content.