The particles suspended inside evaporating sessile droplets can be assembled into microscopic objects with long-ranged ordered structure. The air-water droplet interface guides the assembly and determines the shape of the resulting micropatches. We report the results of a systematic study of the mechanism of interface-templated assembly on substrates of controlled contact angle. The kinetics of drying were examined by measurements of droplet profiles, and it was found that the rate matched diffusion-limited evaporation well. The shape of the droplets and of the resulting assemblies was correlated to the dynamics of the receding contact line. The effects of major parameters controlling the process, including contact angle, particle concentration, and electrolyte, were investigated in detail. A variety of micropatch shapes were observed and categorized within the parameter space. The in-depth characterization of the process allowed the optimization of the assembly and the formulation of protocols for the deposition of nanostructured patches of different diameter, thickness, and shape.
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http://dx.doi.org/10.1021/la702129b | DOI Listing |
Langmuir
January 2025
A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119071 Moscow, Russia.
The results of an investigation of an impact of the structure of recently synthesized bis(trifluoromethylsulfonyl)imide mono- and dicationic ionic liquids on their properties and behavior as lubricants for slippery liquid infused superhydrophobic coatings are presented for a wide temperature range. In this study, a new approach based on monitoring the surface tension of a liquid sessile droplet on top of a coating was exploited for the analysis of the evolution of the coating properties in prolonged contact with the liquid. It was found that the continuous contact with water flow results in slippery property degradation according to two different scenarios.
View Article and Find Full Text PDFMater Horiz
January 2025
Soft Matter Lab, Department of Chemical Engineering, Shiv Nadar Institution of Eminence Deemed to be University, Greater Noida, 201314, India.
This study focuses on fabricating photonic crystals (PCs) by surfactant-based particle capture at the gas-liquid interface of evaporating sessile droplets. The captured particles form interfacial films, resulting in ordered monolayer depositions manifesting iridescent structural colors. The particle dynamics behind the ordered arrangement is delineated.
View Article and Find Full Text PDFLangmuir
January 2025
Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin 300134, China.
Self-cleaning applications based on bionic surface designs requires an in-depth understanding of unique and complex wetting and evaporation processes of sessile droplets on natural biosurfaces. To this end, hydrophobic bamboo and Kalanchoe blossfeldiana leaves are excellent candidates for self-cleaning applications, but various properties, such as the heat and mass transfer processes during evaporation, remain unknown. Here, the dynamics of contact angle, radius, and heat and mass transfer during evaporation of sessile droplets on bamboo and Kalanchoe blossfeldiana leaves with roughness in the range 2.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan Campus, 170 Kessels Road, Brisbane, QLD 4111, Australia.
The evaporation dynamics of sessile droplets on re-entrant microstructures are critical for applications in microfluidics, thermal management, and self-cleaning surfaces. Re-entrant structures, such as mushroom-like shapes with overhanging features, trap air beneath droplets to enhance non-wettability. The present study examines the evaporation of a water droplet on silicon carbide (SiC) and silicon dioxide (SiO) re-entrant structures, focusing on the effects of material composition and solid area fraction on volume reduction, contact angle, and evaporation modes.
View Article and Find Full Text PDFBiomimetics (Basel)
November 2024
Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
In nature, engineering technology and daily life, wetting phenomena are widespread and have essential roles and significance. Bionics is becoming increasingly important nowadays and exploring the mechanism that influences biomimetic surface microstructure on droplet wetting process and heat and mass transfer characteristics is becoming more meaningful. In this paper, based on photolithography technology, SU-8 photoresist was used as raw material to prepare biomimetic surfaces with microstructures in various arrangements.
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