Polymer‐Coated Organic Crystals with Solvent‐Resistant Capacity and Optical Waveguiding Function

Abstract Recently, luminescent organic crystals have been widely studied as new optoelectronic materials. However, corrosion and dissolution of organic crystals by solvents have always been a great challenge for the application of organic crystals in various fields. In this work, we propose a general method of fabricating a solvent‐resistant coating to prevent organic crystals from being corroded or dissolved by organic solvents. The coatings involved layer‐by‐layer assembly of poly(diallyldimethylammonium) (PDDA) and poly(styrenesulfonate) (PSS) onto crystals, followed by immersing the coated crystals into polyvinyl alcohol (PVA) aqueous solutions for 2 minutes. The coated crystals can remain intact over 24 h in common organic solvents without being damaged and even insoluble in dichloromethane for 5 days. Moreover, the thin and transparent coatings have little effect on the optical properties of crystals which still have excellent optical waveguide performance with the coatings.