Hydrophobization Of Up-Conversion Luminescent Films Based On Nanocellulose/Mf2:Ho Particles (M = Sr, Ca) By Acrylic Resin

Luminescent hydrophobic composite films based on nanocrystalline (CNC) and nanofibrillated (CNF) cellulose matrix with up-conversion MF2:Ho (M = Ca, Sr) particles and acrylic resin (ACR) as a coating have been synthesized. Flexible, translucent composite films were obtained by molding from the CNC/CNF suspensions with up-conversion particles. ACR coating was applied to the composite film by spraying. Studies have shown that ACR coating with a layer thickness of 7 - 10 mu m provides hydrophobic properties for the films, increasing the water contact angle up to 100 +/- 2 degrees with a simultaneous improvement in the luminescent properties. Transparency of CNC/CNF/MF2:Ho-ACR films in the visible and near IR region improves by 20 - 25 % without compromising the flexibility and thermal stability. The manufactured water-resistant composite films can be utilized as potential photonics materials, in particular for visualization of near-IR laser radiation and luminescent labels.