Heterointerface Effects in Electrospun Carbon Nanotube/Poly(vinylidene difluoride) Nanofibrous Mats for Microwave Absorption

Developing highly flexible, mechanically strong, and highly efficient microwave absorption materials is urgently needed to solve the electromagnetic (EM) wave pollution problems in the areas of fast-growing electronic devices. Herein, poly(vinylidene difluoride) (PVDF) composite nanofibrous mats combined with functionalized carbon nanotubes (CNTs) were fabricated by a facile electrospinning process. The hydrogen-bonding heterointerfaces between PVDF and acidified CNTs (a-CNTs) favored interfacial polarization relaxation compared with the covalent heterointerfaces between PVDF and aminated CNTs (NH2–CNTs), resulting in better microwave absorption performance. Furthermore, 4,4′-diaminodiphenylsulfone (DDS) was adopted as the chemical cross-linking agent. The PVDF nanocomposite nanofibrous mats with 0.25 wt % DDS exhibited excellent microwave absorbing properties with a minimum reflection loss (RLmin) of −30.4 dB at 7.2 GHz and a thickness of 3.4 mm as well as an effective absorption bandwidth of 5.0 GHz at a thickness of 1.6 mm. More importantly, the mechanical properties were improved simultaneously, because of the cross-linking reaction occurring within the PVDF nanofibers. A tensile strength and a modulus of 1.2 and 21.7 MPa were achieved, respectively. The provided strategy would facilitate the design of highly flexible and mechanically strong electrospun nanofibrous mats for microwave absorption applications.