Fabrication of High Thermal Conductivity Nanodiamond/Aramid Nanofiber Composite Films with Superior Multifunctional Properties

Abstract

Polymer-based thermally conductive materials are preferred for heat dissipation owing to their low density, flexibility, low cost, and easy processing. Researchers have been trying to develop a polymer-based composite film with excellent thermal conductivity (TC), mechanical strength, thermal stability, and electrical properties. However, synergistically achieving these properties in a single material is still a challenge. To address the above requirements, we prepared poly(diallyldimethylammonium chloride)-functionalized nanodiamond (ND@PDDA)/aramid nanofiber (ANF) composite films using a self-assembly strategy. Owing to a strong interfacial interaction arising from electrostatic attraction, ND particles attract strongly along the ANF axis to form ANF/ND “core–sheath” arrangements. These assemblies self-construct three-dimensional thermally conductive networks through ANF gelation precipitation, which was analyzed as the key parameter for the realization of high thermal performances. The as-prepared ND@PDDA/ANF composite films exhibited high in-plane and through-plane TCs up to 30.99 and 6.34 W/m·K, respectively, at a 50 wt % functionalized ND loading, representing the optimal values among all previously reported polymer-based electrical insulating composite films. Furthermore, the nanocomposites also achieved other properties necessary for realistic applications, such as outstanding mechanical properties, excellent thermal stability, ultra-low thermal expansion coefficient, excellent electrical insulation, low dielectric constant, low dielectric loss, and outstanding flame retardancy. Thus, this excellent comprehensive performance enables the ND@PDDA/ANF composite films to be used as advanced multifunctional nanocomposites in thermal management, flexible electronics, and intelligent wearable equipment.

Effect of the Structure of Epoxy Monomers and Curing Agents: Toward Making Intrinsically Highly Thermally Conductive and Low-Dielectric Epoxy Resins

“…This was ascribed to the high energy of C–F bonds in BPAF, which required a higher temperature to break. Additionally, LCE + BPAF, LCE + DDM, and E-51 + DDM resins showed relatively constant heat resistance indexes ( T HRI ) of 176.9, 174.2, and 178.0 °C, while the E-51 + BPAF resin showed a slightly lower T HRI of 169.1 °C. Besides, the LCE + DDM resin displayed the highest final carbon residue of 22.5%, while the E-51 + BPAF resin exhibited the lowest of 7.1%, which was consistent with the above analysis.…”

Self-Reinforced Doping Strategy in the Multiscale PMIA Paper for High Mechanical Properties and Insulating Performance

“…The dielectric constant and the value of E b of each component are the main concerns that significantly influence the composite voltage-withstanding performance. Because of the different dielectric constant between AMFs (>3) and ANFs (2.3–3), − the electric field distortion would appear at the interfaces under the high voltage, decreasing the value of E b . This issue is extremely dramatic and dominates the breakdown process in the samples with a low AMF doping ratio.…”

Nickel nanoparticle decorated silicon carbide as a thermal filler in thermal conductive aramid nanofiber-based composite films for heat dissipation applications

“…Polymer ber thermal conductive lms are an emerging material for thermal management with excellent properties such as lightweight, exibility and electrical insulation in the elds of nanocomposite reinforcement, high-performance heating systems and exible electronics. [1][2][3] In particular, electronic devices are in great need of paper-based lms with anisotropic thermal conductivity and good mechanical properties. 4 Poly(pphenylene terephthalate) (PPTA) bers, known as aramid bers, have rigid molecular chains that are partially connected and extended.…”