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Abstract In this work, multifunctional polyurethane-based phase change materials with zinc oxide (ZnO) and graphene aerogel (GA) were prepared through facile impregnation. ZnO and GA improved the latent heat of the system from 86.8 J/g to 108.1 J/g for the heterogeneous nucleation and chemical mitigations. Furthermore, the photo-/electro-thermal energy conversion efficiency of the system with ZnO and GA is 80.1%, 84.4%, respectively, for the efficient light absorption of ZnO and GA as well as the electrical conductivity of GA. The as-prepared materials with high latent heat, excellent form-stability, remarkable thermal stability as well as reliability, efficient light-/electro-thermal energy conversion, have great prospects for applying in energy harvesting, conversion and storage devices like solar heater, smart textile and greenhouse. Graphical abstract GA serves as supporting skeleton, light absorbent, electricity conductive pathways and thermal barrier. While ZnO acts as nucleation agent, crosslinking agent as well as UV absorbent. Thus, the system with high latent heat is form-stable, light/electro responsive and thermal stability. fx1 Highlights • The air-dried GA serves skeleton and electricity conductive pathways. • ZnO improved the performance of system for heterogeneous nucleating and effective UV absorption. • The thermal stability was improved a lot for the thermal barrier of GA. [ABSTRACT FROM AUTHOR]

Abstract In this study, polyurethane-based solid-solid phase change materials with halloysite nanotubes (HNTs)-hybrid graphene aerogel (GA) have been fabricated through vacuum impregnation. As a supporting skeleton, the air-dried HNTs-GA with continuous porous structure endows the system with excellent light-thermal (η = 75.6%) and electro-thermal (η = 67.2%) energy conversion and storage ability. HNTs not only improve the reduction degree of GA, but also enhance the latent heat of the system through heterogeneous nucleation effects. The synthesized materials with high latent heat, excellent thermal reliability and stability, remarkable light/electro-thermal energy conversion ability show great potentials in applications of energy storage devices. Graphical abstract When exposed to the solar heating or supplied by a power, the system could absorb the light quickly and convert it to heat, or transfer the electro to thermal energy, which make the crystals in the system to melt and the thermal energy is stored. Image 1 [ABSTRACT FROM AUTHOR]

Graphical abstract The crystallization of PEG parts could be continuously improved with the decrease of GO size owing to the increase of heterogeneous nucleation density and mitigation of the chemical and physical restrictions of segments. Highlights • The crystallization of PEG in system get a lot enhancement. • The phase change performance of the system is GO size-dependent. • The interaction among crosslinking network plays an important role. Abstract In this study, the size effects of graphene oxide (GO) sheets on the phase change behaviors of crosslinking polyurethane system have been investigated. The experimental results show that phase change performance of the system is connected closely to the heterogeneous nucleation, physical confinements from GO and interactions in the system, which are inseparable from the specific surface area and the contents of oxygen functional groups depending on the size. This work has a theoretical significance to design thermal energy storage materials with desired properties. [ABSTRACT FROM AUTHOR]

Crosslinking polyurethane-based solid-solid phase change materials with in situ reduced graphene oxide (GO) sheets were fabricated by a facile solvothermal treatment. GO sheets could give their full play to the enhancement of the system, which can endow the system with outstanding form-stability over 100 °C for the synergistic effect with hexamethylene diisocyanate biuret, and remarkable light-thermal conversion efficiency up to 78.7% due to the simultaneous in situ reduction of GO. The phase change enthalpy increases to 127.3 J/g from 86.8 J/g with 3.8 wt% GO for the nucleation and alleviating effects in the system. Meanwhile, the system has improved thermal stability and favorable thermal reproducibility. Therefore, the synthesized materials with comprehensive properties would be perspective to be used in energy storage devices such as solar energy collector system. [ABSTRACT FROM AUTHOR]

Polyurethane-based solid-solid phase change materials were first synthesized using polyethylene glycol (PEG) and hexamethylene diisocyanate biuret (HDIB), and the influence of halloysite nanotubes (HNTs) on this system was investigated. HNTs can not only serve as crosslinking agent in synergy with HDIB, which reinforces the solid-solid phase change properties of the system that has no leakage even at the temperature that 40 °C higher above the melting temperature of PEG, but also greatly improve the latent heat of the system from 86.8 to 118.7 J/g, as a result of heterogeneous nucleation effect, which can make up partial latent heat loss caused by crosslinking. Also, HNTs endows the system with excellent thermal stability, where the temperature at 5% weight loss is increased by 53 °C. The synthesized PCMs have extensive applying prospects in thermal energy storage fields. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) crosslinked polyurethane-based solid–solid phase change materials, composed by polyethylene glycol (PEG) and hexamethylene diisocyanate biuret (HDIB), were fabricated in-situ polymerization. GO sheets could support the excellent solid framework at 100 °C and prevent the leakage of melt in synergy with HDIB by physical and chemical crosslinking network. Meanwhile, GO sheets act as heterogeneous nucleation agents that make the crystallization temperature of system rise to 34.0 °C from 24.8 °C with 14.5 wt‰ GO. Whereas, GO have little effect on the latent heat, which may be an offset of the nucleation and confinement. Besides, the tensile strength increased to 21. 7 from 10.2 MPa with 14.5 wt‰ GO and Young’s modulus increased to 471.5 from 180.1 MPa for 44.6 wt‰ one. Also, the strain at break has a slight promotion within 14.5 wt‰ GO. The synthesized system would be potential to be applied in thermal energy storage fields. [ABSTRACT FROM AUTHOR]

Light-driven PEG/Ti 3 C 2 T x form-stable phase change films for energy storage crosslinked by Co2+ were prepared through facile solution mixing. It is the strong interactions among PEG , Ti 3 C 2 T x and Co2+ that endowed the system with excellent form-stability with only 5.0 wt% supporting. And the latent heat of samples was 142.1 J/g with light-thermal conversion and storage efficiency higher than 86.9%. Meanwhile, the samples possessed improved thermal stability and favorable thermal reliability. The fabricated films with comprehensive properties shows great perspective to be used in energy storage devices. Ti 3 C 2 T x acting as light absorber and heater imparts the film with excellent light-thermal conversion and storage efficiency. Co2+ serves as cosslinker and works with Ti 3 C 2 T x endowing form-stability. [Display omitted] • PEG/Ti 3 C 2 T x film crosslinked by Co2+ showed excellent form-stability. • Samples have high latent heat and light-thermal conversion and storage efficiency. • Thermal stability got improved with Ti 3 C 2 T x. [ABSTRACT FROM AUTHOR]