Preparation of Phase Change Melt Marbles with High Thermal Stability by Spontaneous Shrinkage and Encapsulation

Abstract

Liquid marbles (LMs) are widely used in the fields of microfluids, gas sensitivity equipment, and microreactors. However, the thermal stability of the encapsulated liquid poses difficulty to the hightemperature stability of LMs. In this study, polar phase-change materials (PCMs) with high melting points were used as the encapsulated liquid of LMs. According to the required temperature, suitable PCMs were selected as the core and encapsulated by hydrophobic SiO 2 particles to form melt marbles (MMs). The types of PCMs used to prepare the MMs include erythritol, elemental sulfur, urea, and molten salts. Based on the premixed melting method, a series of MMs with high melting points and thermal stability were successfully developed. The highest acceptable temperature of the MMs exceeded 323 °C, and the evaporation rate of erythritol MMs was less than 1% at 140 °C in 8 h. Thus, the MMs maintained their excellent stability through multiple phase transitions. In the molten state, the MMs exhibited the properties of bounce ability, cuttability, and deformation resistance. The performance of the PCMs in energy storage and release during phase transition demonstrates their potential applications in the field of heat storage.

Simple Fabrication of PDMS-Grafted Hydrophobic Iron Oxide Particles for Oil–Water Separation and Stimuli-Responsive Liquid Marbles

“…The mechanical robustness of an LM measures the stability of the marble under high pressures, impacts, and physical deformations. − The mechanical durability of the prepared LMs was investigated by dropping the marbles of volume 10 and 5 μL from different heights, and the corresponding information is shown in Videos S6 and S7. It was observed that the 5 μL LM bounces off after dropping from a height of 3.5 cm, whereas the 10 μL LM bounces off after dropping from a height of 2.5 cm, indicating the dependence of LM volume on the mechanical durability.…”

Janus liquid marbles: Fabrication techniques, recent developments, and applications

“…LMs are potentially useful in various fields because of their ease of manipulability. LMs are used as gas sensors, 8–10 micro‐reactors, 26,63 micro‐pumps, 76 micro‐bioreactors, 35 storage units, 10,11 and a medium for cultivating micro‐organisms and cells 38 . The incorporation of different particles of different properties will widen the applicability of marbles in various fields.…”

“…5 In contrast to bare liquid droplets, the encapsulating porous particle layer of the liquid marble (LM) partially isolates the core liquid from the surroundings, thereby reducing evaporation losses. 6,7 Such a system permits the gas/vapor exchange between the encapsulated particle layers, 8,9 which facilitates the marble to act as a storage unit 10,11 and sensor. 8,9 Combining the properties of the particles, core liquid, and substrate, the LMs can be actuated with external stimuli such as light, [12][13][14][15] temperature, 16,17 pH, [18][19][20][21][22] electric field, [23][24][25] magnetic field, [26][27][28][29][30] and so on, or surfactants.…”

Preparation of Oriented Superhydrophobic Surface to Reduce Agglomeration in Preparing Melt Marbles

“…30 In our previous work, we proposed the concept of melting marbles based on liquid marbles, which can be prepared by a premixed melting method. 23,31 The result has shown that urea melt marbles (UMM) also have similar structures and properties to liquid marbles. Melt marbles should belong to a category of liquid marbles.…”

“…The marbles are prone to agglomeration and breakage in collision and transportation, which greatly reduces the efficiency of the preparation of liquid/melt marbles. Particularly, for melt marbles such as urea and sulfur, the increased viscosity and density of the materials often result in reduced elasticity and sphericity of the marbles. , Consequently, this further hampers their overall performance and effectiveness in applications. At the same time, the phase change process involved in preparing and transporting the melt marbles makes it more difficult to control the granulation process.…”