Epoxy-acrylate/nano-SiO2 hybrid formulations for optoelectronic coatings

Abstract

Hybrid organic-inorganic materials have gained increasing attention from researchers due to their environmental benefits and wide application potential. In this study, a novel method for fabricating UV-curable and bifunctional epoxy acrylates (EA) – silica hybrid coatings was developed, utilizing surface-modified nanoparticles with sizes ranging from 12 to 18 nm as fillers. Three types of EA monomer were synthesized using conventional methods. The inorganic phase of silica was obtained in the presence of polyacrylic acid, which served as a surfactant, and subsequently modified with 3-(trimethoxysilyl)propyl acrylate before being introduced into the monomer dispersion. The impact of SiO₂ nanoparticles on the rheology of the final coating precursor was examined, demonstrating the capacity to alter the viscosity of the formulation from several mPa·s to over 10 Pa·s, as well as to modify the refractive index (RI) from 1.43 to 1.55.

The composite materials synthesized in the visible range (400–800 nm) exhibited a transmittance of over 96 % following exposure to UV radiation (350–390 nm) and thermal curing at temperatures below 100 °C. The resulting materials demonstrate excellent heat resistance up to 200 °C and adhesive ability. The surfaces of the hybrid coatings were examined using scanning electron microscopy (SEM), which revealed a smooth surface devoid of any microcracks. The potential of using the composite as a photoresist for organic optoelectronic systems was demonstrated. This class of transparent photomaterials can be employed in photoconversion microstructures based on QDs, which are widely used in QLED displays, as well as in sealing coatings for photovoltaic organic devices.