Study on antireflection SiO2 coatings fabricated by layer-by-layer deposition

Multifunctional (poly(diallyldimethyl ammonium chloride)/ sodium poly(4-styrene sulfonate)) _n ((PDDA/PSS) _n ) thin films were fabricated by layer-by-layer assembled on the glass substrate. The monolayer silica nanoparticles were prepared on the (PDDA/PSS) _n films. The SiO₂-polyelectrolyte coatings exhibit antireflection properties with low refractive index (as low as 1.22). Interestingly, wavelengths of maximum transmittance could be well tailored by simply changing the particle size of SiO₂. A maximum transmittance of 97.03% in the visible spectral range is achieved for the particle size of 100 nm SiO₂ films. The coatings also show excellent mechanical stability and good adhesion to substrates. The easy availability of the raw materials and simplicity of the fabrication method for such films might make them be potentially useful for various applications.