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Energy storage and conservation are receiving increased attention due to rising global energy demands. Therefore, the development of energy storage materials is crucial. Thermal energy storage (TES) systems based on phase change materials (PCMs) have increased in prominence over the past two decades, not only because of their outstanding heat storage capacities but also their superior thermal energy regulation capability. However, issues such as leakage and low thermal conductivity limit their applicability in a variety of settings. Carbon-based materials such as graphene and its derivatives can be utilized to surmount these obstacles. This study examines the recent advancements in graphene-based phase change composites (PCCs), where graphene-based nanostructures such as graphene, graphene oxide (GO), functionalized graphene/GO, and graphene aerogel (GA) are incorporated into PCMs to substantially enhance their shape stability and thermal conductivity that could be translated to better storage capacity, durability, and temperature response, thus boosting their attractiveness for TES systems. In addition, the applications of these graphene-based PCCs in various TES disciplines, such as energy conservation in buildings, solar utilization, and battery thermal management, are discussed and summarized.

High-performance electrochromic (EC) and electrofluorochromic (EFC) materials have garnered considerable interest due to their diverse applications in smart windows, optoelectronics, optical displays, military camouflage, etc. While many different EC and EFC polymers have been reported, their preparation often requires multiple steps, and their polymer molecular weights are subjected to batch variation. In this work, we prepared two triphenylamine (TPA)-based and two tetraphenylethylene (TPE)-based derivatives functionalized with terminal styryl groups via direct Suzuki coupling with (4-vinylphenyl)boronic acid and vinylboronic acid pinacol ester. The two novel TPE derivatives exhibited green–yellow aggregation-induced emission (AIE). The EC and EFC properties of pre- and post-thermally treated derivatives spin-coated onto ITO–glass substrates were studied. While all four derivatives showed modest absorption changes with applied voltages up to +2.4 V, retaining a high degree of optical transparency, they exhibited obvious EFC properties with the quenching of blue to yellow fluorescence with IOFF/ON contrast ratios of up to 7.0. The findings therefore demonstrate an elegant approach to preparing optically transparent, heat-induced, cross-linkable styryl-functionalized EFC systems.

Coating materials serve the purposes to protect, enhance and/or confer additional functionalities and properties to the underlying object surface or bulk materials. In recent years, nanotechnologies have been extensively incorporated into the functional coatings as manipulation of materials at the nanoscale can impart some unique chemical, mechanical, thermal, surface and photophysical properties that can be exploited to enhance functions required in urban built environments. In this review paper, recent research progresses of several categories of functional coatings were summarized with emphasis on their applications for green and smart buildings. These included hydrophobic coatings, hydrophilic and photocatalytic coatings, coatings for reduction in surface solar radiation as well as phase change materials (PCM) coatings. This review aims to provide a general introduction and research progress on these selected functional coating technologies, starting from the material's fabrication to its application when used in different building components.

Phase Change Materials (PCM) are efficient materials for thermal management and energy storage due to its high latent heat and recyclability. Many strategies have been employed to form stabilize PCMs through their phase transition; however these materials are almost invariably rigid. Herein a novel flexible form-stable PCM composite was successfully prepared by physical mixing and low temperature curing. They were well characterized in terms of various techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), mechanical and leakage test, etc. A leakage test showed that the composite with 50% octadecane loading was form-stable with only 2.44% leakage. From the differential scanning calorimetry (DSC) results, the octadecane/silicone (Oct/Si) composite was found to possess a latent heat of 103.8 J/g, and an upshift in phase transition temperature was also observed from octadecane's melting point of 30.3 °C to between 34.4 and 37.8 °C, probably due to thermal insulation or microencapsulation by the silicone matrix. Thermogravimetric analysis (TGA) data supported its good thermal stability within this temperature range and mechanical testing of the composites further confirmed its flexibility and durability as evidenced by the Young's Modulus at 388.92 kPa and elongation at 341.42%, making Oct/Si composites useful for application in areas of temperature regulation, cooling, energy harvesting and wearable devices.