Search

With the increasing demand for dielectric materials in high-frequency microwave applications, fluoropolymer-based dielectric materials have been widely utilized due to their excellent dielectric and insulation properties. However, the low thermal conductivity limits their ability to meet the thermal dissipation requirements during high-frequency and high-speed signal transmission. The present study introduces a pioneering interface engineering strategy wherein C–F bonds on the surface of ethylene-tetrafluoroethylene copolymer (ETFE) are photo-catalytically activated, enabling successful grafting of poly(glycidyl methacrylate) (PGMA) chain segments. Subsequently, the resulting graft copolymers are blended with thermally conductive h-BN filler to prepare composite dielectric materials. The results demonstrate that the incorporation of PGMA segments significantly enhances the interfacial compatibility between the ETFE matrix and h-BN filler, resulting in composites with a dense microstructure and outstanding dielectric and thermal properties. At a filler content of 30 vol%, the ETFE-g-PGMA@BN composite achieves an in-plane thermal conductivity of 4.2 W (m K)−1 and a through-plane thermal conductivity of 0.77 W (m K)−1. Moreover, at 1 GHz, the composite exhibits a dielectric constant of 2.2 and a dielectric loss of 0.004. This work presents a novel interface design strategy for surface modification of PTFE-based fluoropolymers, expanding their potential applications in printed circuit boards (PCBs) and providing a new direction for the design of polymer-based dielectric materials. [ABSTRACT FROM AUTHOR]

The past years have witnessed a phenomenal growth of the mobile payment market, but how mobile payment affects purchase behavior receives less attention from academics. Recent studies suggested that lower pain of paying may not fully clarify the relationship between mobile payment and increased purchases (i.e., mobile payment effect). The current research first introduced price level in Study 1 and demonstrated that the pain of paying served as an underlying mechanism only in the high‐price condition rather than the low‐price condition. As such, Study 2 was conducted in a low‐price context to address the uncovered mechanisms. We propose a new concept of "pleasure of payment" that is defined as an implicit and consumption‐related hedonic response based on the cue theory of consumption. By tracking spontaneous attention to positive attributes (i.e., benefits) of products, Study 2 demonstrated this implicit pleasure as a psychological mechanism for the mobile payment effect when the pain of paying was not at play. These findings have important implications for mobile payment in research and practice by identifying price level as a boundary condition for the role of pain of paying and understanding the positive downstream consequences of mobile payment usage on consumer psychology. [ABSTRACT FROM AUTHOR]

Achieving high-energy-density polymer dielectrics often involves a trade-off between enhanced permittivity and superior breakdown strength, which limits the miniaturization and integration of thin-film capacitors. In this work, to address this issue, a dipole regulation strategy was employed to fabricate a polar semi-crystalline poly(vinylidene chloride-co-vinyl chloride) (P(VDC-VC)) film. The study demonstrates that the large volume and significant steric hindrance of chlorine atoms endow P(VDC-VC) with high conformational transition barriers, enabling it to maintain a stable TGTG′ conformation and an α-crystal phase under high electric fields. At 1 kHz, P(VDC-VC) exhibits a dielectric constant of 5.1, which is higher than that of most linear dielectrics reported in the literature. Additionally, the stable conformation ensures robust polarization capability and low dielectric loss under high electric fields. The well-organized crystalline regions and the electron–hole trapping ability further reduce the leakage current of the P(VDC-VC) film, achieving a breakdown strength of up to 780 MV m−1. This work successfully decouples the trade-off between high permittivity and elevated breakdown strength via dipole regulation, offering an effective approach and theoretical guidance for the design of high-performance polymer dielectrics. [ABSTRACT FROM AUTHOR]

Polypropylene (PP)‐based dielectric film capacitors cannot meet the rapid development requirements of electromagnetic energy equipment because of their low energy storage density (Ue). The development of new dielectric materials is hampered by the trade‐off between high energy storage properties and thin film processibility for capacitors. This study proposes a strategy to improve the comprehensive energy storage properties of PP films by reconciling the trade‐offs not only between their polarity and crystallinity but also between their energy storage and processing performance. In this approach, a trifluoroethyl methacrylate (TFEMA) modified PP film is fabricated at the kilogram scale. The TFEMA units regulate PP crystallization in the α‐phase, resulting in improved mechanical, dielectric, and energy storage performance. The optimal PP‐g‐TFEMA film exhibits a remarkable breakdown strength (Eb) of 865 MV m−1 and a record Ue of 8.2 J cm−3 at over 90% discharge efficiency. The promising thin film processibility, excellent self‐healing, and long‐term reliability of PP are finely preserved in the aluminum (Al) coated PP‐g‐TFEMA film. These findings present a novel avenue to significantly increase the Ue of film capacitors for long‐term service not only in academia but also in industry. [ABSTRACT FROM AUTHOR]