Robust, Versatile Access to Quasi-Monodispersed Phase Change Sub-Microcapsules via Ab Initio Emulsion Polymerization

Abstract

The phase change sub-microcapsules (PCMCs) with the particle size of 100 nm to 1 μm have a great application potential in the field of hybrid materials for solar energy storage, while the preparation of PCMCs remains challenging without ultrasonic treatment and high-speed (>1000 rpm) homogenization. Herein, PCMCs with readily tunable phase change properties are prepared via facile, robust ab initio emulsion polymerization. The PCMCs present the quasi-monodispersed particle morphologies with the tunable particle size from 159 to 383 nm depending on the loading content of acrylic acid and the free surfactant. The latent heat density and phase change temperature of the PCMCs can be tuned from 66.6 to 115.2 J/g and from 20.8 to 65.4 °C, respectively, depending on the loading content and the type of phase change cores. The PCMCs confirm the latent heat efficiency of about 1, the high thermal reliability, and the high shape stability. The PCMCs can be functionalized by polyaniline coatings with an efficient photothermal effect. The robust, versatile approach to functionalized PCMCs can provide an alternative opportunity for the development of the next-generation smart thermal energy materials.

Engineering Polymeric Phase-Change Sub-Microcapsules with a High Encapsulation Fraction by Facile, Versatile Suspension Polymerization

“…There was no bonding and aggregation between the microcapsule particles, indicating that paraffin had been efficiently encapsulated in the polymer shells of PIBOMA. The average particle size of PCMC- x P gradually increased from 326.48 nm ( x = 50%) to 683.78 nm ( x = 60%) to 737.54 nm ( x = 70%) and then to 911.88 nm ( x = 80%) with x increasing from 50 to 80%, indicating that the content of paraffin has a significant effect on the particle size of PCMC- x P because of the higher hydrophobicity of paraffin compared to that of PIBOMA shells with numerous polar ester groups (Table S8 in SI) . It is proved that PCMCs with different weight fractions of paraffin loading from 50 to 80% can be prepared by the facile suspension polymerization, and the maximum paraffin encapsulation fraction of PCMC- x P can reach 80% by weight.…”

“…Compared to nanocapsules usually prepared via ultrasound or high-speed stirring (≥1000 rpm), phase-change microcapsules with a large specific surface and low thermal conductivity are often prepared by in situ polymerization and interfacial polymerization without ultrasound or high-speed stirring (≥1000 rpm). − Therefore, in contrast to phase-change nano- and microcapsules, phase-change sub-microcapsules (PCMCs) are promising for a broad range of applications . PCMCs are commonly fabricated by emulsion polymerization, miniemulsion polymerization, and suspension polymerization with ultrasonication or high-speed stirring (≥1000 rpm). − Previously, we successfully prepared PCMCs by emulsion polymerization independent of ultrasonication and high-speed stirring (≥1000 rpm), but the encapsulation fraction could only reach 60 wt %, which limits the further application of PCMCs . Therefore, the preparation of PCMCs with a high encapsulation fraction (≥70 wt %) by simple, versatile polymerization without high-speed stirring (≥1000 rpm) and the subsequent functionalization and application will shed light on the design and optimization of PCMCs with a polymeric core–shell structure.…”

“…50−52 Previously, we successfully prepared PCMCs by emulsion polymerization independent of ultrasonication and high-speed stirring (≥1000 rpm), but the encapsulation fraction could only reach 60 wt %, which limits the further application of PCMCs. 11 Therefore, the preparation of PCMCs with a high encapsulation fraction (≥70 wt %) by simple, versatile polymerization without high-speed stirring (≥1000 rpm) and the subsequent functionalization and application will shed light on the design and optimization of PCMCs with a polymeric core−shell structure.…”

“…With the depletion of nonrenewable energy, improving the efficiency of energy and increasing the utilization of sustainable energy have become the trend of future development. − In a wide variety of energy conversions, there is always a portion of heat that is lost in the conversion process. − A large amount of heat is inevitably lost in daily production and life, and about 90% of the global energy budget involves heat conversion. Besides, solar energy is also a sustainable source of thermal energy. ,, Storing thermal energy is a way of storing energy for efficient use of waste heat and solar heat. − Phase-change materials (PCMs) are used to release/absorb thermal energy by melting/crystallizing in a narrow temperature range, which is called latent heat. − PCMs have become one of the most promising methods of storing thermal energy because of their large energy storage density and thermostatic energy storage. , They have great potential applications in smart textiles, smart buildings, batteries, etc. − …”

Defect engineering: the role of cationic vacancies in photocatalysis and electrocatalysis

“…Examples include doping, chemical reduction, electrochemical exfoliation and heat treatment. Jing et al 38 synthesized Y-doped hexagonal Co(OH) 2 (DSA-Y 0.05 -Co(OH) 2 ) catalysts through surface functionalization with suberic acid and a Y-doping strategy. In the neutralization reaction between acid and base at room temperature, Co(OH) 2 is generated, while the introduction of suberic acid results in coordination with certain Co ions.…”