Scalable Sol–Gel Permeation Assembly of Phase Change Layered Film Toward Thermal Management and Light‐Thermal Driving Applications

Abstract

Phase change materials (PCMs) are pivotal in thermal energy management and conversion applications owing to their exceptional thermal energy storage and release characteristics. However, persistent challenges such as poor thermal conductivity and leakage issues have impeded their widespread adoption. While existing approaches mitigate these challenges by constructing and incorporating 3D thermal conductive networks, they are constrained by discontinuous preparation methods and mold size limitations. Herein, a scalable sol–gel permeation assembly strategy is proposed to prepare phase change layered film by in situ filling polyethylene glycol (PEG) in aramid nanofibers (ANF)/graphene nanoplates (GNP) network. Befitting from the laminated network encapsulation effect of ANF and GNP, the phase change film demonstrates leak‐free and stable phase transition behavior, even after undergoing 500 heating/cooling cycles. Moreover, the resulting PEG/ANF/GNP layered film exhibits an impressive in‐plane thermal conductivity of 23.7 W mK−1 at GNP loading of 28.1 vol.%, rendering it suitable for thermal management applications in electronic devices. The phase change layered film possesses exceptional photo‐thermal conversion properties, maintaining temperatures exceeding 90 °C under a light power density of 200 mW cm−2. Capitalizing on the thermally induced flexibility of the phase transition film and its temperature‐dependent stiffness, its utility extended to developing a light‐thermal driving gripper.

Ultrafine Aramid Nanofiber-Assisted Large-Area Dense Stacking of MXene Films for Electromagnetic Interference Shielding and Multisource Thermal Conversion

“…By quantitatively analyzing the degree of orientation of MXene/ANF films, it is evident that the films reinforced with UANF obtain lower full width at half-maxima (fwhm) of 34.8° and orientation factor of 0.78 compared to fwhm of 39.5° and f of 0.71 for the CANF reinforced film (Figures c and S7). ,, This improvement is attributed that the ultrafine diameter of UANF minimizes the insulating gaps between the nanosheets, thereby facilitating a more ordered and compact stacking of the MXene nanosheets. As shown in Figures d and S8, all MA films exhibit sharp peaks with narrow fwhm of (002) peak on the azimuthal plots, indicating the high orientation of MXene in layered films.…”

“…In our previous work, we proposed a high-efficiency wet ball mill-assisted deprotonation (BMAD) method to obtain ultrafine aramid nanofibers (UANF) (1.0−4.0 nm in diameter), and the corresponding nanopaper has a denser stack structure, fewer defects, and higher mechanical properties (tensile strength of 271.7 MPa, toughness 33.1 MJ m −3 ) . Compared with conventional ANF, UANF as binders can effectively reduce the insulating gaps between MXene nanosheets, which can maintain the electrical conductivity meanwhile impart good mechanical properties for the MXene-based layered films . Therefore, it is expected the highly oriented and dense stacking of MXene nanosheets with the assistance of UANF in their laminated films.…”

Enabling Supramolecular Phase Change Materials with High Latent Heat Ability and Recyclability

“…Nowadays, with the continuous development of a society that uses nonrenewable fossil energy as its main source of energy, the energy crisis and the pollution of the environment stemming from its usage are increasingly pronounced. − It is becoming more and more important to use fossil energy more efficiently and environmentally friendly and to develop other clean and renewable energy sources. , So far, people have developed renewable energy sources alternatives like solar, wind, tidal, and biomass energy sources. − Although they are very environmentally friendly, they all suffer from the problems of poor stability and continuity, which limit their widespread use . As for energy utilization, thermal energy storage technology has been gradually emphasized as a technology that can realize efficient energy conversion and storage. , Thermal energy storage technology mainly utilizes the two ways of phase change energy storage and chemical reaction energy storage to realize the storage of thermal energy. , Among them, organic phase change materials (PCMs) have garnered extensive research and application across various sectors including aerospace, construction, clothing and other fields in recent years because of their advantages such as high energy storage density, small temperature variation in the energy storage process and good long-term stability. − Paraffin, fatty alcohols, and PEG , are the main raw materials used in organic PCMs. Among them, PEG has the advantages of high latent heat, customizable phase change temperature, low subcooling, small volume change during phase change, nontoxicity and environmentally friendly nature, which propels PEG into the forefront of research interest in recent years. − …”