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Self-assembly; micro and nanoparticles; depletion zone; evaporation; core–shell particles.

We report experimental studies on the self-assembly of silica microspheres and Laponite nanoplatelets (NPs) in evaporating sessile droplets and in thin films, respectively. A ring-like stain of the silica microspheres with positionalorder is observed after the evaporation of sessile droplets due to the coffee-ring effect. This effect is suppressed in the binary mixtures of silica microspheres and Laponite NPs. A depletion zone has been observed in the mixtures during the sessile droplet evaporation, the width of which can be tuned by varying the compositions. We demonstrate a simple method for preparing core–shell particles by evaporating thin films of binary mixtures in which the Laponite NPs self-assemble to form a crystalline shell on the amorphous silica microspheres.We present a possible orientation of the Laponite NPs in the shell.

RAVI KUMAR PUJALA¹ DEVIKA VENKUZHY SUDHAKARAN² SURAJIT DHARA²

1. Soft and Active Matter Group, Department of Physics, Indian Institute of Science Education and Research (IISER), Tirupati, Andhra Pradesh 517507, India
2. School of Physics, University of Hyderabad, Hyderabad 500046, India

Published

29 July 2020

Manuscript received

17 August 2019

Accepted

24 November 2019

Final version published online

29 July 2020