Preparation And Properties Of Hydrophobic Rare Earth Coordination Polymer Fluorescent Coatings

The application of hydrophobic coatings involves all aspects of people’s lives,such as anti-icing applied to wires,corrosion-resisting on metal substrates,self-cleaning on material surfaces etc.Rare-earth complexes are widely used in optical,electrical and magnetic fields.However,they are unstable and easy influenced by environment,which can result in fluorescence unstable and quench,further limits their applications.In this paper,the microspheres were prepared by emulsion polymerization,the fluorescence coatings were obtained by coordinating the microspheres with rare earth ions.The coordination structures between rare earth ions and polymer,the effect of hydrophobicity on the fluorescence properties and the stability of the underwater fluorescence were especially investigated.The core-shell polydivinylbenzene-acrylic polymer microspheres with different acrylic acid（AA）content were prepared by core-shell emulsion polymerization.The dynamic light scattering（DLS）curve and scanning electron microscope（SEM）indicated the size of core-shell polymer microspheres was about 1μm.Acrylic acid was polymerized with divinylbenzene confirmed by IR spectra.The obtained core-shell microspheres,phenanthroline,acetylacetone as ligands and rare earth ions(Eu³⁺or Tb³⁺)were coordinated in ethanol then coated on a glass plate.IR spectra,elemental analysis and inductive coupling plasmas（ICP）were used to confirm chemical structure.And by SEM,EDS,Mapping,it can be seen that the rare earth ions are attached on the surface of the microspheres and distributed uniformly.Fluorescence intensity test showed that within 3 wt%¹8 wt%of AA content,the fluorescence intensity increases with the increase of AA content and no concentration quenching occurred.Fluorescence microscopy showed the luminescence of the coating was composed with many dots.The TGA curve showed that decomposition temperature of the coating is up to 350°C,which exhibites excellent thermal stability.The hydrophobicity of fluorescence coatings was studied,when the AA content under 12 wt%,a highly hydrophobic coating with a contact angle of more than 120°was obtained.Through the regulation of the reaction conditions and the addition of reaction aids,the fluorine-containing monomers are polymerized,and obtained core-shell particles with the core layer was composed with polydivinylbenzene,the shell layer was composed with fluoropolymers,polyacrylic acid and polydivinylbenzene.IR,EDS and mapping analysis proved that the fluoromonomer was polymerized.The core-shell structure was identified by transmission electron microscope（TEM）.The prepared fluorine-containing fluorescent coatings obeyed the Cassie-Baxter model and has a mirror effect.The static water contact angle of the florescent（AA 6 wt%）is 157°and the rolling angle of is 5.6°.The wettability of the coating at different pH values showed that the coating was good at anti-acid and anti-corrosion.The coating can be applied to different substrates（paper sheets,iron sheets,wood）and still exhibits superhydrophobicity,The water droplets can take away the carbon black in the surface without wetting the coating,which revealed good self-cleaning performance.The superhydrophobic properties of the fluorine-containing fluorescent coatings remain stable in the acid and alkali environment,the fluorescence intensity of the fluorine-containing fluorescent coatings in aqueous solution or 10 wt%NaCl solution after 24h was basically unchanged.