The construction of conductive network and the design of material structure are the key points of polymer-based shielding materials. Herein, we reported a MXene/PDMS composite foam material with adjustable cell structure and high efficiency electromagnetic interference (EMI) shielding. Few-layered MXene is used as a conductive filler to construct three-dimensional conductive networks by in situ chemical etching. Meanwhile, a series of polystyrene microspheres with different sizes were prepared by applying suspension polymerization method as templates to introduce different cell sizes and densities for PDMS-based materials. The density and EMI shielding performance of composites can be improved by adjusting the cell structure. Compared with the unfoamed MXene/PDMS composites, the composite foam in this work not only reduces the material density greatly but also improves the microwave absorption performance with smaller cell size. This method provides a simple and effective guide for changing material density and absorbing mechanism by introducing cell structure into polymer-based materials in the future. 相似文献
It is particularly difficult to prepare a foam CPC material because its porous structure makes it hard to form a conductive network. We utilized acetone‐assisted dispersion to disperse CNTs into PU foam and successfully prepared a lightweight conductive CNT/assembled PU foam composite. The NTC effect, which exclusively exists in the melt state CPC materials, has unexpectedly been observed in the solid‐state lightweight conductive CNT/sPU composite. Higher gas fraction and lower matrix modulus could result in stronger NTC effect. The mechanism that thermal expansion of gas wrapped in the cellular structure induces more perfect conductive paths has been proposed to satisfactorily elucidate the NTC effect and its gas fraction and matrix modulus dependence.
