Quick Heat Dissipation in Absorption-Dominated Microwave Shielding Properties of Flexible Poly(vinylidene fluoride)/Carbon Nanotube/Co Composite Films with Anisotropy-Shaped Co (Flowers or Chains)

Abstract

The facile fabrication of thin flexible electromagnetic interference (EMI) shielding materials with fast heat dissipation for adaptable tuning in both civil and military applications is in urgent demand. In our work, the flexible poly(vinylidene fluoride) (PVDF)/carbon nanotube (CNT) composite films decorated with anisotropy-shaped Co in flowers or chains were prepared and studied. The results showed that by increasing the Co filler contents, the EC (electrical conductivity), TC (thermal conductivity), and EMI shielding properties of such PVDF/CNT/Co (flowers or chains) flexible films were significantly improved. In contrast, the PVDF/CNT/Co-chain flexible films exhibit higher performance with respect to the EC, TC, and EMI shielding properties. Total shielding of 35.3 and 32.2 dB were, respectively, obtained by the PVDF/CNT/6 wt % Cochain with an EC of 2.28 S/cm and the PVDF/CNT/6 wt % Co-flower with an EC of 1.94 S/cm at a film thickness of 0.3 mm. Possibly owing to the conductive dissipation, interfacial polarization, magnetic loss, multiple reflections, and scattering of EM waves, such flexible composite films possessed a remarkable absorption-dominated EMI shielding behavior. These new composite films with enhanced TC are easily able to transform microwave energy into Joule heating systems, making themselves greatly potential for effective EMI shielding as well as rapid heat dissipation.

Flexible PEBAX/graphene electromagnetic shielding composite films with a negative pressure effect of resistance for pressure sensors applications

“…It is well accepted that the formation of conductive network would inuence the electrical conductivity and further affect the EMI shielding properties. 6,21,41 To further identify the distribution of graphene and connected state between conductive graphene, SEM observation was performed ( Fig. 3).…”

“…[1][2][3][4] Therefore, much attention has been paid to the development of novel and exceptional EMI shielding materials. [5][6][7][8] Promising electromagnetic shielding materials should possess the characteristics of strong blocking performance, high electrical conductivity, excellent strength and anti-corrosion ability. Generally, metals and metal alloys display outstanding EMI shielding effectiveness due to excellent electrical conductivity.…”

Enhancement of electromagnetic interference shielding from the synergism between Cu@Ni nanorods and carbon materials in flexible composite films

“…Ni [17][18][19][20], Fe [21][22][23], and Co [24,25] in composites have a strong absorption performance, but there is a tradeoff with a higher filler content and a greater thickness of the EMI shielding materials. Accordingly, incorporation of nanofillers is favorable to accumulate each single fundamental property in a solitaire composite for promoting the EMI shielding performance [26].…”

Electromagnetic Interference Shield of Highly Thermal-Conducting, Light-Weight, and Flexible Electrospun Nylon 66 Nanofiber-Silver Multi-Layer Film

“…Otherwise, the inherently low thermal conductivity of the polymer composite may result in an unwanted excessive temperature increase and consequently degrade the performance and long-term durability of shielded devices. To address this issue, there have been studies aimed at dissipating the heat energy generated by adding fillers with high thermal conductivity [ 35 , 36 , 37 , 38 ] or by depositing metal films [ 39 , 40 ].…”