Microfluidic Production of Monodisperse Biopolymer Microcapsules for Latent Heat Storage

Abstract

Microencapsulation of phase change materials in a polymer shell is a promising technology to prevent them from leakage and to use them as a handleable powder state. However, the microencapsulation process is a timeconsuming process because the typical shell-forming step requires polymerization or evaporation of the solvent. In this study, we report a simple and rapid flow process to prepare monodisperse biocompatible cellulose acetate (CA) microcapsules encapsulating n-hexadecane (HD) for latent heat storage applications. The microcapsules were prepared by combining microfluidic droplet formation and subsequent rapid solvent removal from the droplets by solvent diffusion. The diameter and shell thickness of the microcapsules could be controlled by adjusting the flow rate and the HDto-CA weight ratio in the dispersed phase. We found that 1-hexadecanol added to the microcapsules played the role of a nucleation agent and mitigated the supercooling phenomenon during crystallization. Furthermore, cross-linking of the CA shell with poly(propylene glycol), tolylene 2,4-diisocyanate terminated, resulted in the formation of a thin and dense shell. The microcapsules exhibited a 66 wt % encapsulation efficiency and a 176 J g −1 latent heat storage capacity, with negligible supercooling. We believe that this microflow process can contribute to the preparation of environmentally friendly microcapsules for heat storage applications.

Methods for the Synthesis of Phase Change Material Microcapsules with Enhanced Thermophysical Properties—A State-of-the-Art Review

“…The results showed that the microcapsules had an average latent heat of 87.5 J/g with a calculated encapsulation efficiency of 96.5%. 2022) [169] adopted the same approach to formulate microcapsules where a monodisperse biocompatible cellulose acetate (CA) constituted the shell materials and HD was used as the core material. Figure 23 shows the schematic representation of the microflow process used to produce the cellulose acetate-n-hexadecane microcapsules.…”

Advances in Microfluidic Technologies for Energy Storage and Release Systems

“…The PCMs are first emulsified into droplets using the inner and middle fluids and then the droplets are encapsulated into the final product by the outer fluid (Figure 9d). Many materials have been explored for core/shell microencapsulated PCMs, including n ‐hexadecane/polyethylene glycol diacrylate (PEGDA), [ 133 ] water/trimethylolpropane ethoxylate triacrylate (ETPTA), [ 133 ] silicone/ n ‐hexadecyl bromide, [ 134 ] cellulose acetate/ n ‐hexadecane, [ 135 ] paraffin/isophorone diisocyanate and tetraethyenepentamine, [ 136 ] sodium acetate/acrylate, [ 137 ] n ‐tetradecane and n ‐hexadecane/silicon, [ 128 ] and n ‐heptadecane/hexanediol diacrylate polymer. [ 138 ] Further, nanoparticles can be incorporated into the microcapsules as exemplified by Lone et al who incorporated Fe 3 O 4 nanoparticles into the core of n ‐octadecane/polyurea microcapsules (Figure 9e).…”

Engineering Interconnected Open-Porous Particles via Microfluidics Using Bijel Droplets as Structural Templates

“…In this study, we developed a microfluidic process to prepare spherical particles − with an interconnected open-porous structure using a bijel droplet as the template. A dispersed phase composed of a hydrophobic monomer, water, ethanol (cosolvent), photoinitiator, silica nanoparticles, and CTAB was used as the dispersed phase.…”