Evaporation-driven control of uniform nanoparticle deposition using ternary mixture droplets

Document Type

Article

Publication Date

9-1-2026

Abstract

This study investigates evaporation-driven deposition of ternary mixture droplets laden with graphene nanoplatelets (GNPs) on polydimethylsiloxane (PDMS) substrates to achieve uniform films suitable for flexible and wearable device applications. Deposition patterns obtained from single-component, binary, and ternary mixtures were compared to elucidate the mechanisms governing uniform deposition patterns. While deionized water droplets produced substantial inner patterns and binary mixtures exhibited only partial suppression, the ternary mixture containing water, ethanol, and surfactant consistently yielded highly uniform deposition patterns with reduced rim accumulation and enhanced interior particle coverage. This uniformity is attributed to the coupled effects of volatility contrast and interfacial tension differences, which are consistent with inferred Marangoni-assisted particle redistribution during evaporation. Concentration-dependent experiments revealed distinct deposition regimes ranging from non-uniform film formation to uniform films across different ethanol-surfactant combinations. To quantitatively interpret these transitions, a modified contact-line pinning model was employed to evaluate the ratio of the characteristic contact-line recession-onset time to the characteristic particle-migration time during evaporation. The model provided a semi-empirical framework for rationalizing the experimentally observed pattern transitions. Furthermore, increasing droplet volume improved deposition homogeneity and suppressed cracking, as confirmed by field-emission scanning electron microscopy and three-dimensional profilometry.

Publication Title

Experimental Thermal and Fluid Science

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