High-Throughput Spherical Supraparticle Self-Assembly by Enhanced Evaporation of Colloidal Water Droplets Through Thin Film of Water-Soluble Oil

This paper proposes a microfluidic device that facilitates high-throughput and reliable spherical supraparticle self-assembly through enhanced evaporation of water droplets through thin film of water-soluble/low volatile olive oil. The olive oil, containing water droplets generated from a flow-focusing device, is spontaneously spread thinly throughout interpillar spaces of an open-microfluidic evaporator. The thin olive oil film on an evaporator offers enhanced water dissolution to oil and diffusion of dissolved water from oil to air, which can allow complete droplet evaporation within 10 min without any temperature and humidity control. Finally, high-throughput and reliable spherical supraparticle self-assembly are achievable, which can construct tens of micron-sized particles with nanoparticle building blocks.