Fig. 5: Drying behavior of pigment particle dispersions.
From: Versatile strategy for homogeneous drying patterns of dispersed particles
a SEM images of the particles. Scale bar 1 µm. b–g Drying behavior of aqueous dispersions of pure (b–d) and PVA-modified (e–g) goethite (b, e), titanium dioxide (c, f) and hematite (d, g) particles. h–o Drying behavior of pure (h–k) and modified (l–o) hematite particle dispersed in polar solvents. Scale bar: 1 mm. Aqueous dispersions are dried on a native silicon substrate (b–g) and dispersions in dimethyl formamide (DMF) (h, l), heptanol (i, m), butanol (j, n) and ethanol (k, o) are dried on a fluorinated substrate to ensure a well-defined sessile droplet. While the pure particles either form a coffee ring (b–d, i–k) or a dot-like deposit (caused by the high contact angle) (h), the PVA-coated particle dispersions dried mostly homogeneously (e–g, l–n), while for ethanolic dispersions (o) the coffee ring started to reappear.
