Evaporation-driven Supraparticle Synthesis by Self-Lubricating Colloidal Dispersion Microdrops

Abstract

The surface-templated evaporation-driven (S-TED) method that uses liquid-repellent surfaces has attracted considerable attention for its use in fabricating supraparticles of defined shape, size, and porosity. However, challenges in achieving mass production have impeded the widespread adoption of the S-TED method. To overcome this limit, we introduce an evaporation-driven “multiple supraparticle” synthesis by drying arrays of self-lubricating colloidal dispersion microdrops. To facilitate this synthetic method, a hydrophilic micropattern is prepared on a hydrophobic substrate as a template. During the removal of the substrate out of a dispersion, liquid drops are trapped and generate a microdrop array. To produce supraparticles, the contact lines of the trapped drops must be able to recede freely during evaporation. However, hydrophilic micropatterns induce strong contact line pinning for microdrops that hinders supraparticle formation. Herein, we solve this contradiction by employing an Ouzo-like colloidal dispersion, where we can control the wettability of the drop trapping domain. The self-lubrication effect provided by the Ouzo-like solution enables smooth movement of the drops’ contact lines during evaporation, thereby resulting in the successful fabrication of supraparticle arrays even within the trapping domain. This strategy offers a promising and scalable approach for large-scale evaporation-driven supraparticle synthesis with a potential for extension to various primary colloidal particles, further broadening its applicability.

Liquid marbles: review of recent progress in physical properties, formation techniques, and lab-in-a-marble applications in microreactors and biosensors

“…A similar study was reported for the droplets of a colloidal dispersion deposited on a superhydrophobic surface; evaporation and the absence of contact line pinning allowed the formation of supraparticles. 120–122 However, this method does not enable the formation of core–shell type supraparticles that make LMs a valuable tool for forming such complex materials.…”

Molecular Rotors for In Situ Viscosity Mapping during Evaporation of Confined Fluid Mixtures

“…Evaporating sessile droplets over solid substrates is also an important geometry, which can be encountered in various applications like spray cooling, 4 chemical and biological assays, 5 medical diagnosis, 6 spreading of pesticides, 7 or material self-assembly. 8 In the past decades, such configuration witnessed an increased interest in the context of inkjet printing, 9 which has overcome the usual application of printing on paper 10 to become a cheap and versatile method for additive manufacturing, employed for flexible organic and inorganic electronics, 11 light-emitting devices, 12 pharmaceutical products, 13 biomaterials, 14 or filtration membranes. 15 From a fundamental point of view, the dynamics of evaporation of a liquid is an old problem 16 and has been the subject of intense experimental and modeling efforts for decades.…”

“…Most of the coatings start under the form of films of liquid suspensions spread over substrates, as for paints or lithium-ion batteries among other examples. Evaporating sessile droplets over solid substrates is also an important geometry, which can be encountered in various applications like spray cooling, chemical and biological assays, medical diagnosis, spreading of pesticides, or material self-assembly . In the past decades, such configuration witnessed an increased interest in the context of inkjet printing, which has overcome the usual application of printing on paper to become a cheap and versatile method for additive manufacturing, employed for flexible organic and inorganic electronics, light-emitting devices, pharmaceutical products, biomaterials, or filtration membranes …”