摘要
Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films have important application values in the fields of 5G communication technology,wearable electronic devices and artificial intelligence.In this work,Fe_(3)O_(4)/polyamic acid(PAA)nanofiber films are prepared by in-situ polymerization and electrospinning technology,and Ti_(3)C_(2)T_(x)nanosheets are deposited on the surface of the Fe_(3)O_(4)/PAA nanofiber films via vacuum-assisted filtration.Then,Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/polyimide(PI))composite films are obtained by thermal imidization.The two sides of the Janus films exhibit completely different properties.The Fe_(3)O_(4)/PI side has excellent hydrophobicity and insulation property,and the Ti_(3)C_(2)T_(x)side has hydrophilicity and terrific conductivity.When the mass fraction of Ti_(3)C_(2)T_(x)is 80 wt.%,the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite film has excellent EMI shielding performances and mechanical properties,with EMI shielding effectiveness,tensile strength and Young’s modulus reaching 66 dB,114.5 MPa and 5.8 GPa,respectively.At the same time,electromagnetic waves show different absorption shielding effectiveness(SEA)when incident from two sides of the Janus films.When the electromagnetic waves are incident from the Fe_(3)O_(4)/PI side,the SEA of the Janus film is 58 dB,much higher than that when the electromagnetic waves are incident from the Ti_(3)C_(2)T_(x)side(39 dB).In addition,the Ti_(3)C_(2)T_(x)side of the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite films also has excellent electrothermal and photothermal conversion performances.When the applied voltage is 4 V,the stable surface temperature reaches 108°C;when it is irradiated by simulated sunlight with power density of 200 mW/cm2,the stable surface temperature reaches 95℃.
基金
supports from the National Natural Science Foundation of China(Nos.U21A2093 and 51903145)
Fundamental Research Funds for the Central Universities(No.D5000210627)
Y.L.Z.would like to thank the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2021107)
This work is also financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.
