Morphology-dependent properties and swelling-induced transition in ‘sodium-alginate/urea’ thin films

The paper investigates the competing and morphology-dependent wetting and imbibition behaviours of ‘sodium-alginate/urea’ films that are currently used as thickeners in inkjet printing processes, dealing specifically with the structural changes of the coating within the swelled spot of the contacting (wetting) liquid drop. Depending on the initial morphology of the coating, the re-drying of the swelled wetting spot was found to lead to re-crystallization morphologies that are qualitatively different in both their texture and physicochemical properties. Well beyond the investigated ‘alginate/urea’ mixture, these results well highlight the critical influence that swelling-induced morphological re-constructions might have on interface phenomena in general, and in particular, on the wetting, impregnation and adhesion of solvent-processed polymeric assemblies.