Multifunctional MXene/natural rubber composite films with exceptional flexibility and durability

Recent advancement of MXene (Ti3C2Tx) nanosheets has demonstrated the wide range of applications benefiting from its lightweight and high electrical conductivity. It possesses great potential as electromagnetic interference (EMI) shielding material owing to its layered structure and high conductivity. Currently, the major shortcoming of utilizing MXene as EMI shielding films is the lack of flexibility and high oxidation tendency to TiO2 in humid condition, which might significantly impair their mechanical and electrical properties. To overcome this drawback, MXene/natural rubber (NR) composite films were prepared using a suction filtration of the mixed suspension containing MXene (Ti3C2Tx) and NR. The strong interaction between NR and MXene results in the formation of lightweight, interconnected and hydrophobic composite films. The MXene/NR60% film demonstrates high water contact angle (104°) and low density (1.28 g/cm3). It also shows a tensile strength of 34 MPa, elongation at break of 4.5%, and cyclic folding endurance of 7425 times, which are 1.5, 5.6 and 62 times of pure MXene film respectively. Microscale combustion calorimeter results show that higher concentration of MXene leads to more significant flame retardancy of MXene/NR composite films. MXene/NR60% film at a thickness of 65.6 μm exhibits outstanding EMI shielding efficiency 47.8 dB. After soaking in water for 15 days followed by bending 6000 times, this film retains high EMI shielding efficiency (32.8 dB), indicating an excellent durability. The high performance MXene/NR composite films combined with their mechanical endurance provide a new material for protecting wearable electronic devices and other sensitive equipment against microwaves.