Technologies are generally described to increase a surface smoothness of a 3D printed article implementing a water-based treatment using layer by layer (LBL) deposition. An initial 3D printed article having an anionic surface may be treated with a first aqueous solution comprising at least one polycation that may bind to the anionic surface to produce a first treated surface, which may be rinsed with water to remove the first aqueous solution. The first treated surface may be treated with a second aqueous solution comprising at least one anionic microparticle that may bind to the polycation to produce a final 3D printed article having. a second treated surface, which may be rinsed with water to remove the second aqueous solution. The bound polycation and anionic microparticle may be present as a single layer in the final 3D printed article that may act as a conformal coating to increase the surface smoothness.