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. 2022 May 23;13:2840. doi: 10.1038/s41467-022-30497-z

Fig. 1. Mitigating the coffee ring effect by surface modification of dispersed particles.

Fig. 1

a Schematic illustration of the process: An aqueous polystyrene (PS) particle dispersion is mixed with excess polyvinyl alcohol polymer (PVA) solution. The polymer partially adsorbs onto the particles. Centrifugation and redispersion removes excess, non-adsorbed polymer. b Surface tension of the different aqueous dispersions used to investigate the drying behavior. c–e Drying behavior of a reference colloidal dispersion (c), the same dispersion with addition of PVA (weight ratio 1:1) (d), and after removal of non-adsorbed PVA (e). In (c–e) top image: Optical micrograph of the dried dispersions. Scale bar: 1 mm. Middle image: Cross-sectional grey value distribution after drying. Bottom image: Confocal microscopy side projections (z–r plane) of the drying dispersions using fluorescently labelled PS particles. Scale bar: 25 µm.