Link：https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202102285

In  this  work,  we  first  covered  organic  crystals  with  polymer composite  coatings  which  involved  layer-by-layer  assembled (PDDA/PSS)9  polyelectrolyte  multilayers  (PEMs)  and  a succeeding  PVA  layer .  The  PVA-(PDDA/PSS)9 films can prevent organic crystals from dissolving in most organic solvents including dichloromethane (DCM), chloroform, acetone, ethyl acetate, tetrahydrofuran (THF) and toluene up to 24 h. It can be reasonably speculated  that  the  coated crystals  can remain stable in organic nonpolar solvent such as petroleum ether and n-hexane for a longer time compared with in organic polar solvents. Moreover, the PVA-(PDDA/PSS)9-coated single crystals still have the same optical properties of the original crystals because the coatings are colorless, transparent, thin and uniform. As a result, the  optical  waveguide  of  the  PVA-(PDDA/PSS)9-coated  single crystals which originally have optical waveguiding function can be implemented in organic solvents as well. This work has  distinctive  significance  for  organic  crystals  which  have potential applicable value in optoelectronic devices.