Infiltration and dimensional scaling of inkjet droplets onpapers with different surface chemistry
(English)Manuscript (preprint) (Other academic)
We investigate experimentally and theoretically the spontaneous imbibition of complex inkjet formulations utilizing paper capillary rise and imbibition of inkjet drops. We compare two commercially available papers of the same structure but with different chemistry, one of them surface treated with CaCl. This additive is known to improve print quality when water based pigmented inkjet inks are used by rapidly aggregating the colorant pigments close to, or even on, the surface of the paper. In a previous publication we showed that the key components in the destabilization mechanism of the ink are the dispersing polymers that contain carboxylate groups which interact specifically with the Ca2+ cation. Here we demonstrate the impact of this destabilization effect on the spontaneous imbibition of ink formulations comprised of these polymers, and find that on large scale and long time the imbibition rate is slower in the CaCl2 containing paper compare to the CaCl2 free paper, as shown in paper capillary rise experiments, but on a much smaller scale and shorter times relevant for single inkjet drops no significant differences are observed. We approximate the paper structure to a two dimensional anisotropic porous material, and using Darcy’s law as a base derive dimensionless groups that scale drop imbibition.. This derivation is an expansion of the previously published dimensional scaling of drop imbibition on thick isotropic porous material. We obtain the average global system properties required, by performing sets of drop imbibition experiments where drops are impinged on random paper locations, and use the results to calculate the average volume loss of a single imbibing drop. This averageing procedure is then used in the dimensional scaling.
IdentifiersURN: urn:nbn:se:kth:diva-152902OAI: oai:DiVA.org:kth-152902DiVA: diva2:751955
QS 20142014-10-022014-10-022014-10-02Bibliographically approved