Ultra-Low Loading of Ultra-Small Fe3 O4 Nanoparticles on Nonmodified CNTs to Improve Green EMI Shielding Capability of Rubber Composites

Robust Multifunctional Films with Excellent EMI Shielding, Anti-Peeling, and Joule Heating Performances Enabled by an Encapsulated Highly Conductive Fabric Strategy

Recently, the issue of electromagnetic pollution has become increasingly prominent. Flexible polymer films with various conductive fillers are preferred to address this problem due to their highly efficient and durable electromagnetic interference (EMI) shielding performance. However, their applications are restricted by the unbalanced and insufficient electromagnetic wave absorption and shielding capabilities, as well as the weak interlayer bonding force. In this work, robust flexible multifunctional AgNW/MXene/NiCo-C (AMN) films are fabricated by hierarchical casting assembly and an encapsulated conductive fabric strategy. The synergistic effect of the conductive-absorption integrated sandwich core fabric and the conductive encapsulation layer collaborate to provide excellent absorption-dominated EMI shielding (EMI SEmax = 89.12 dB with an ultralow reflectivity value of 0.19) and Joule heating (a high temperature of 103.5 °C at 4.5 V) performances. Besides, AMN films with embedded fabrics as a reinforcement structure achieved enhanced peel (1.97 N mm-1) and tensile (7.85 MPa) strengths through an interface enhancement process (plasma and pre-immersion treatments). In conclusion, this paper proposes a feasible paradigm to prepare flexible multifunctional conductive films, which demonstrate tremendous potential for applications in the wearable electronics and aerospace fields.

Multilevel structural polylactic acid fabrics for flame retardancy, durability, and electromagnetic interference shielding

The integration of polylactic acid (PLA) fabrics with bio-based flame retardants and conductive MXene addresses the requirements for safe sustainable development and electromagnetic interference (EMI) shielding. The dehydration and carbonization of phytic acid (PA) and polyethylenimine (PEI) were facilitated by employing 3-glycidyl oxy propyl trimethoxsilane (GPTMS) as an organic crosslinking agent, which was covalently bonded to both the flame retardants and the MXene conductive layer. The prepared multifunctional PLA fabric, designated as PA-PEI-MXene-60, exhibits a high Limiting Oxygen Index (LOI) of 35.6 %, a damage length of 3.2 cm, a peak heat release rate (pHRR) reduction of 81.38 %, and total heat release (THR) reduction of 27.03 %, indicating exceptional flame-retardant properties. Concurrently, the MXene conductive layer provides outstanding EMI shielding performance. A subsequent hydrophobic treatment was applied using polydimethylsiloxane (PDMS) coatings, resulting in a water contact angle of 148.8°. Additionally, while the PLA fabrics exhibited remarkable EMI shielding effectiveness at 54 dB. Importantly, despite undergoing repeated bending and abrasion tests, these multifunctional PLA fabrics maintain relatively high EMI shielding efficiency, demonstrating commendable durability. This work significantly contributes to the research and development of bio-based, safe, durable multifunctional flame-retardant materials with EMI shielding capabilities.

Cellulose-derived carbon scaffolds with bidirectional gradient Fe3O4 distribution: Integration of green EMI shielding and thermal management

Cellulose papers (CPs) possess a pore structure, rendering them ideal precursors for carbon scaffolds because of their renewability. However, achieving a tradeoff between high electromagnetic shielding effectiveness and low reflection coefficient poses a tremendous challenge for CP-based carbon scaffolds. To meet the challenge, leveraging the synergistic effect of gravity and evaporation dynamics, laminar CP-based carbon scaffolds with a bidirectional gradient distribution of Fe3O4 nanoparticles were fabricated via immersion, drying, and carbonization processes. The resulting carbon scaffold, owing to the bidirectional gradient structure of magnetic nanoparticles and unique laminar arrangement, exhibited excellent in-plane electrical conductivity (96.3 S/m), superior electromagnetic shielding efficiency (1805.9 dB/cm2 g), low reflection coefficients (0.23), and a high green index (gs, 3.38), suggesting its green shielding capabilities. Furthermore, the laminar structure conferred upon the resultant carbon scaffold a surprisingly anisotropic thermal conductivity, with an in-plane thermal conductivity of 1.73 W/m K compared to a through-plane value of only 0.07 W/m K, confirming the integration of thermal insulation and thermal management functionalities. These green electromagnetic interference shielding materials, coupled with thermal insulation and thermal management properties, hold promising prospects for applications in sensitive devices.

Lightweight Dual-Functional Segregated Nanocomposite Foams for Integrated Infrared Stealth and Absorption-Dominant Electromagnetic Interference Shielding

Lightweight infrared stealth and absorption-dominant electromagnetic interference (EMI) shielding materials are highly desirable in areas of aerospace, weapons, military and wearable electronics. Herein, lightweight and high-efficiency dual-functional segregated nanocomposite foams with microcellular structures are developed for integrated infrared stealth and absorption-dominant EMI shielding via the efficient and scalable supercritical CO2 (SC-CO2) foaming combined with hydrogen bonding assembly and compression molding strategy. The obtained lightweight segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity, and outstanding absorption-dominant EMI shielding performances attributed to the synchronous construction of microcellular structures and segregated structures. Particularly, the segregated nanocomposite foams present a large radiation temperature reduction of 70.2 °C at the object temperature of 100 °C, and a significantly improved EM wave absorptivity/reflectivity (A/R) ratio of 2.15 at an ultralow Ti3C2Tx content of 1.7 vol%. Moreover, the segregated nanocomposite foams exhibit outstanding working reliability and stability upon dynamic compression cycles. The results demonstrate that the lightweight and high-efficiency dual-functional segregated nanocomposite foams have excellent potentials for infrared stealth and absorption-dominant EMI shielding applications in aerospace, weapons, military and wearable electronics.

Graphene-Based Hybrid Fillers for Rubber Composites

Graphene and its derivatives have been confirmed to be among the best fillers for rubber due to their excellent properties, such as high mechanical strength, improved interface interaction, and strain-induced crystallization capabilities. Graphene rubber materials can be widely used in tires, shoes, high-barrier conductive seals, electromagnetic shielding seals, shock absorbers, etc. In order to reduce the graphene loading and endow more desirable functions to rubber materials, graphene-based hybrid fillers are extensively employed, which can effectively enhance the performance of rubber composites. This review briefly summarizes the recent research on rubber composites with graphene-based hybrid fillers consisting of carbon black, silica, carbon nanotubes, metal oxide, and one-dimensional nanowires. The preparation methods, performance improvements, and applications of different graphene-based hybrid fillers/rubber composites have been investigated. This study also focuses on methods that can ensure the effectiveness of graphene hybrid fillers in reinforcing rubber composites. Furthermore, the enhanced mechanism of graphene- and graphene derivative-based hybrid fillers in rubber composites is investigated to provide a foundation for future studies.