Design and synthesis of composite films with excellent microwave absorption performance using polydimethylsiloxane as flexible frame

The preparation of flexible ultra-thin microwave absorption composite films for practical application is a known challenge. In this work, we use polydimethylsiloxane as the frame, extra conducting electric carbon black and carbonyl iron powder as absorbents. The microwave absorption performances of composite films can be well adjusted by changing the mass ratio of extra conducting electric carbon black and carbonyl iron powder. Meanwhile, the maximum reflection loss can reach -50.53 dB with a thickness of 1.63 mm, while the effective absorption bandwidth can achieve 4.80 GHz at a 1.48 mm thickness. The excellent microwave absorption performance can be attributed to the synergistic effect of good impedance matching, magnetic loss, dielectric loss and conduction loss. Importantly, the preparation of this ultra-thin composite film explores the application of polydimethylsiloxane as a flexible framework material in microwave absorption field.