Drying morphologies and related wetting and impregnation behaviours of ‘sodium-alginate/urea’ inkjet printing thickeners

The drying conditions of wet processed polymers, in general, and of high water-sorbing polymers, in particular are known to strongly affect their physical properties. We here investigate these drying morphologies for ‘alginate–urea’ compounds which are widely used as functional coatings in textile. We show how drastically the wetting and impregnation behaviours of the coating are affected by the drying conditions and resulting crystallisation morphologies. Furthermore, the contact of water drops during wetting measurements was found to induce morphological reconstruction through ‘swelling/re-drying’ process, leading to the formation of large and highly anisotropic needle crystals in coatings that were initially amorphous. Beyond the studied ‘alginate–urea’ system, these results provide insights into the evaporation-driven crystallization of solvent-processed compounded materials.