Engineering Interfacial Processes at Mini-Micro-Nano Scales Using Sessile Droplet Architecture.

Area of Science:

• Interfacial Science
• Fluid Dynamics
• Materials Science

Background:

• Sessile droplets are crucial for industrial and biological applications, including surface patterning, 3D printing, and medical diagnostics.
• Drying sessile droplets offer a high-throughput, low-volume processing technique vital for medical diagnosis.
• These droplets serve as a platform to study interfacial processes from wetting and evaporation to microfluidic transport and nanometric interparticle forces.

Purpose of the Study:

• To review the coupled physics of evaporation flow and contact-line-driven particle transport in sessile colloidal droplets.
• To present methodologies for controlling particle assembly within drying droplets.
• To highlight the significance of understanding droplet-scale interfacial processes for applications like 3D printing.

Main Methods:

• Analysis of natural alterations in droplet vaporization affecting evaporative patterns and contact line dynamics.
• Investigation of external stimuli including thermal, mechanical, vapor confinement, and chemical methods to influence particle transport.
• Examination of controlled interfacial oscillations to augment evaporation-driven particle transport.

Main Results:

• Evaporation and contact line dynamics naturally modulate internal flow and final particle assembly.
• External stimuli such as thermal, mechanical, confinement, and chemical factors provide control over particle transport.
• Controlled interfacial oscillations can significantly enhance particle transport in sessile droplets.

Conclusions:

• Manipulating interfacial mechanisms during droplet drying allows control over final particle morphologies.
• This control is highly suitable for fabrication, mixing, and diagnostic applications.
• Understanding and controlling droplet evaporation dynamics is essential for advanced material assembly and applications.