Synthesis and electromagnetic interference shielding effectiveness of ordered mesoporous carbon filled poly(methyl methacrylate) composite films

Thin films of ordered mesoporous carbon (OMC) with various mass fractions (0-40 wt%) composited with poly(methyl methacrylate) (PMMA) have been fabricated via a solvent casting method for electromagnetic interference (EMI) shielding materials. The OMC (actually CMK-3) embedded inside the polymer matrix endows the composite films with high electric conductivity which goes up with the increase of the OMC mass fraction. Through a four-probe method, it has been found that this novel composite film has a typical percolation threshold of 12.8 wt% CMK-3. Furthermore, the measured EMI shielding efficiency (SE) in 8.0-12.0 GHz (X-band) of the OMC/PMMA composite films has a strong dependence on the OMC content. The contribution of the absorption to total EMI SE of the system is larger than that of the reflection, that is, the absorption is more than 70%. For the composite film with 40 wt% OMC (0.4 mm in thickness), the mean EMI SE reaches 18.5 dB, indicating its promising application in EMI shielding.