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Microencapsulation of paraffin with melamine formaldehyde shell (Pn@MF) shows the drawbacks of low thermal conductivity. Hence, we constructed SiO2 shells on Pn@MF phase change microcapsules by interfacial polycondensation to obtain Pn@MF@SiO2 double‐shelled microcapsules. The effect of tetraethoxysilane (TEOS) contents on the performance of Pn@MF@SiO2 was discussed in detail. As the TEOS contents increased, the thermal conductivity of Pn@MF@SiO2 gradually increased, reaching up to 0.376 W m−1 K−1. The Pn@MF@SiO2 have exhibited superior leakage‐proof properties and thermal reliability through double‐shelled protection, and the highest reduction in leakage rate reached 45.06 % compared to Pn@MF microcapsules. The Pn@MF@SiO2‐3 with the lowest enthalpy still exhibit a latent heat storage capacity of more than 176 J/g, which displayed outstanding latent heat storage/release capability and good anti‐permeable property. [ABSTRACT FROM AUTHOR]

A series of paraffin@poly(methyl methacrylate) phase‐change microcapsules (Pn@PMMA) were synthesized by suspension polymerization. The prepared Pn@PMMA had excellent latent heat storage and release properties (ΔHm=183.2 J/g, ΔHc=181.9 J/g), excellent thermal stability and cycle durability of at least 100 cycles. The effects of emulsifier type, cross‐linking agent content and core/shell mass ratio on structure and properties of Pn@PMMA were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR) and differential scanning calorimetry (DSC). The morphology of Pn@PMMA exhibited spherical profile with styrene‐maleic anhydride (SMA) as emulsifier and the agglomeration was significantly reduced. The enthalpy of the microcapsules was significantly improved with the addition of crosslinker. The anti‐permeability of Pn@PMMA subsequently further improved with continued increasing amount of cross‐linker. Besides, the enthalpy and anti‐leaking property of the microcapsules progressively reduced with the core/shell mass ratio decreased, while the thermal conductivity gradually increased. Therefore, the results showed that the Pn@PMMA with the enthalpy of 183.2 J/g and the leakage rate of 4.72 %, which displayed a high thermal reliability potential for thermal energy storage and temperature regulation. [ABSTRACT FROM AUTHOR]

• Graphene carbon aerogels (cPCG) were fabricated by high-temperature carbonization. • Thermal conductivity of cPCG@PEG (polyethylene glycol) rises with carbonization temperature. • Carbonization can enhance the solar-thermal conversion efficiency of cPCG@PEG. • This design broadens the application of cPCG@PEG in solar energy utilization. Phase change materials (PCMs) have a wide range of applications in latent heat storage and thermal management. However, their practical use is hindered by high leakage rates and low thermal conductivity. To address these issues, polyvinyl alcohol/carboxylated carbon nanotubes/graphene hybrid aerogels (PCG) were carbonized at high temperatures to obtain polyvinyl alcohol/carboxylated carbon nanotubes/graphene carbon aerogels (cPCG). Polyethylene glycol (PEG) was then encapsulated within cPCG to form cPCG@PEG shape-stabilized PCMs (SSPCMs). These cPCG@PEG SSPCMs demonstrated excellent thermal conductivity (0.843 W•m-1•K-1) and superior solar-thermal conversion performance (91.8%). Additionally, the latent heat of cPCG@PEG showed a minimal decrease even after 100 melt-crystallization cycles. An experimental setup was designed to regulate the temperature of solar photovoltaic (PV) panels using cPCG@PEG. The results indicated that cPCG@PEG effectively managed the temperature of solar PV panels under varying light conditions. This study presents a novel approach for enhancing the application of porous PCMs in solar energy utilization and thermal management of equipment. [Display omitted] [ABSTRACT FROM AUTHOR]

• MF/GA double-skeleton with excellent mechanical property is constructed by in situ self-assembly method. • Dual-skeleton based MF/GA@PEG SSPCMs possess superior shape memory property and solar-thermal conversion ability. • Anti-leakage mechanism of MF/GA@PEG SSPCMs is proposed. • This design strategy provides a new application of MF/GA@PEG SSPCMs in microelectronic devices. Polyethylene glycol (PEG) is widely used for thermal energy storage, but its practical application is limited by its strong rigidity, poor shape stability. In this work, a kind of melamine foam/graphene aerogel (MF/GA) double-skeleton was prepared, then PEG was stably encapsulated into MF/GA by vacuum melt impregnation method to obtain MF/GA@PEG shape-stabilized phase change materials (SSPCMs). Structural characterization and performance tests were performed on MF/GA@PEG SSPCMs, including morphological observation, latent heat, thermal conductivity, shape stability, and photothermal conversion capability. The experimental results show that the MF/GA@PEG SSPCMs show high energy storage density (168.3 J/g), good shape stability, shape memory performance and excellent solar-thermal energy conversion capability with a high efficiency of 84.8%, the thermal conductivity of MF/GA@PEG SSPCMs is 161% higher than that of pure PEG. The MF/GA@PEG SSPCMs with comprehensive properties have promising application in solar-thermal energy storage and thermal management in microelectronic devices. [Display omitted] [ABSTRACT FROM AUTHOR]

A series of reversibly thermochromic phase-change microcapsules (TC@MF), demonstrating excellent energy storage and release properties, were synthesized using melamine formaldehyde resin (MF) encapsulated ternary complex consisting of crystal violet lactone (CVL), 2,2-Di-(4-hydroxyphenyl) propane (BPA), and n-hexadecanol. The microstructure, chemical composition, thermal storage capacity, thermal cycling durability, discoloration effect, and thermal regulation performance of TC@MF with different core contents were investigated in detail. With core contents gradually increasing, the chromatic aberration values (ΔE) value of TC@MF increased from 38.23 to 71.69, the melting enthalpy (ΔH m) gradually increased from 180.2 J/g to 218.6 J/g while the leak-proof performance decreased gradually. The TC@MF-2 with the best comprehensive performance has exhibited superior latent heat storage (ΔH m = 192.2 J/g), high chromatic aberration values (ΔE = 57.31), and well leak-proof properties (5.61 %). Furthermore, the thermal performance, morphology, and reversible color reliability of TC@MF-2 remained stable through 100 thermal heating and cooling cycles, demonstrating excellent thermal cycling stability. In summary, such multifunctional microcapsules can directly reflect the energy saturation and depletion states in phase change material applications through color changes. That might be conducive to expanding the value of its practical application in the field of latent heat energy storage, including smart fabrics or fibers, commodity packaging, thermal sensors, reversible thermochromic coatings and solar energy storage, and so on. [Display omitted] [ABSTRACT FROM AUTHOR]