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Authors
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Bai, W.; Lin, Y.; Du, Y.; Fang, Y.; Zhang, F.; Bonaccurso, E.; Xiao, W.; Shen, Y.; Auernhammer, G. K.; Zhang, X.; Zhao, B.
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Title
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Directional and gradient patterning from sub-microliter colloidal droplet evaporation on inclined and stretched soft substrates
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Date
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07.05.2026
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Number
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0
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Abstract
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Precise control of particle deposition patterns from evaporating colloidal droplets is vital in manufacturing advanced materials and devices. Despite significant progress, the interplay between substrate mechanical anisotropy and gravity in shaping the patterns remains underexplored. Here, we report an intriguing phenomenon of orientation-dependent sub-microliter droplet evaporation and particle deposition on inclined, stretched soft substrates. We demonstrate that sequential control of substrate stretching, inclination, and rotation can effectively tailor complex deposition patterns. Stretching creates an anisotropic wetting state, which pinches the droplet into a spindle shape during late-stage evaporation. At the droplet's tapered ends, reduced contact angles enhance local capillary flows, driving particle accumulation and forming an elongated ring pattern with periodic rim height gradient. Inclination biases both surrounding airflow and particle sedimentation, resulting in asymmetric, downward-cumulated deposition patterns. Remarkably, rotating the inclined stretched substrate reorients this asymmetry, allowing precise manipulation of the deposit's densest regions and final morphology. This work deepens the fundamental understanding of anisotropic droplet dynamics and offers a simple yet powerful strategy for engineering tailored micropatterns.
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Publisher
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Wiley
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Wikidata
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Citation
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Droplet (2026) e70070
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DOI
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https://doi.org/10.1002/dro2.70070
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Tags
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