Fig. 2. Drying behavior of pure and polymer-modified particle dispersions.

Drying patterns of aqueous dispersions containing ellipsoidal (a, d) and spherical PS particles (b, e), prepared by embedding in a PVA matrix and subsequent purification by centrifugation. Left: Optical microscopy images. Scale bar: 1 mm. Right: SEM images of the droplet edge. Scale bar: 5 µm. a, b When washed with water, both ellipsoids and spheres show a uniform drying pattern. d, e When washed with an IPA/water mixture, both dispersions show the typical coffee ring. c, f Drying behavior of a pure silica particle dispersion (f) and silica particles surface-functionalized with grafted linear poly(N-isopropylacrylamide) chains (c).