Novel polyvinyl alcohol/polyacrylic acid hydrogels achieve excellent electromagnetic shielding by the modification of CNTs

Carbon nanotubes (CNTs) are widely used as conductive fillers because of their lightweight and easy modification. However, their poor dispersion in solvents limits their otherwise excellent performance. The anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and (3-aminopropyl) triethoxysilane (KH550) were used as modifiers to inhibit the agglomeration of multi-walled CNTs. A high toughness, strong electromagnetic shielding (EMI) hydrogel was prepared by blending polyvinyl alcohol (PVA) and polyacrylic acid (PAA) hydrogel. Addition of a modifier promoted the uniform dispersion of multi-walled CNTs, but also improved the mechanical properties of the hydrogels. An elongation at break (233.9%) and compressive strength (≈2.89 MPa) of PVA/PAA/K-CNTs hydrogel with 0.5 wt% K-CNTs, 8 wt% PVA and 2 wt% PAA were noted. More encouragingly, the total electromagnetic shielding effectiveness was 28.89 dB at just 1-mm thickness. This work provides a general approach for CNT functionalization that may be of great interest to industry.