Sol–gel-derived nanoparticles coated liquid entities: liquid marbles, liquid plasticine, and flat interface

Abstract

Particle-coated liquid entities are the basis of many useful products, such as foams, emulsions, bijels, and liquid marbles. Particles stabilized at the liquid-air interface have been widely explored during the past two decades. Such interfaces usually consist of micro- to nano-sized particles that often tend to aggregate and lose transparency as well as the smoothness of the interface. Recently, these obstacles have been overcome by using sol-gel-derived silica nanoparticle coating. Sol-gel-derived nanoparticles offer a monolayer structure at the interface with high transparency and reproducibility. This paper critically reviews three sol-gel-derived liquid entities: Liquid marbles, Liquid plasticine, and nanoparticle-coated flat interface. Liquid marble, a particle-covered droplet, was significantly explored for its application as a container in many biological and chemical processes. Unlike powder-derived liquid marble, sol-gel-derived liquid marble can be formed into any desired shape, commonly known as liquid plasticine. Monolayer-covered sol-gel entities also offer a simple physical platform for investigating many fundamental properties of particle-coated interfaces. In the present review, starting from its preparation to the application, all critical aspects are summarized. Some unaddressed issues compared to the powder LM are also discussed for future research.

Tunable encapsulation of sessile droplets with solid and liquid shells

“…A PTFE powder of 35 µm, purchased from Sigma-Aldrich, was used to prepare LM. The liquid droplet of the desired volume was gently rolled several times for the preparation of LM 50 . Control of the mass loading was obtained by fixing the initial volume of the LM and subsequently increasing its volume to 10 by merging it with the bare water droplet (Supplementary Fig.…”

Two modes of contact‐time reduction in the impact of particle‐coated droplets on superhydrophobic surfaces

“…Separately, an aqueous solution of 2. rolled on the particle beds. 44 Control of the ML was obtained by fixing the initial volume of the LM and subsequently increasing its volume to 8.2 μL by merging it with a bare water droplet. The merging process was carried out on a SHP surface to avoid breakage.…”

“…PTFE powders with average particle diameters of 800 nm, 35 μm, and 200 μm were used to prepare LMs. An 8.2 μL DI water core was rolled on the particle beds 44 . Control of the ML was obtained by fixing the initial volume of the LM and subsequently increasing its volume to 8.2 μL by merging it with a bare water droplet.…”

Advances in Microscale Droplet Generation and Manipulation

“…The generation and manipulation of larger millimeter-sized (microliter) droplets are essential for many biomedical applications. − In this size range, digital microfluidic devices using electric fields are appealing due to their simple design and capability to work with small sample volumes. , The manipulation of the millimetric-size droplet is usually performed through various electric and magnetic platforms. , Droplet actuation using DC or low-frequency (Hz) electric fields on dielectric-coated electrodes is termed electrowetting on dielectric (EWOD) . Electrowetting has been explored for multiple applications because it enables programmability, reconfigurability, and the realization of portable hand-held systems .…”