Wet-Spinning Fabrication of Poly(3,4-vinyl dioxythiophene): Poly(styrenesulfonate)/Sodium Alginate Fibers Function as Intelligent Off/On Switchable Microwave Absorber

Exploring flexible, high-efficiency microwave absorption materials remains challenging to meet the growing demands for more wearable and portable electronics. Herein, highly flexible and mechanically robust poly(3,4-vinyl dioxythiophene): poly(styrenesulfonate) (PEDOT: PSS)/sodium alginate (SA) composite fibers (PA) were successfully prepared via an environmentally friendly wet-spinning technique. The fabricated PA fibers achieve a maximum breaking strength of 283.77 MPa benefited from the dual cross-linking interaction of a rich hydrogen bonding network and ionic bond. Notably, the inherent anisotropy endows conductive PA with a functional switch potential for microwave absorption “on” and “off” by altering the angle of the fiber arrangement. At an alignment of 45°, the single-layer PA12 fiber composite panel (FCP) exhibits excellent microwave absorption (MA) performance with a minimum reflection loss (RLmin) of −56.2 dB and a broadened effective absorption bandwidth (EAB) of 3.78 gigahertz (GHz) at 4.18 mm. Whereas FCP-PA12 can turn off the MA property by changing to 90°. The intelligent tunable MA property may be attributed to the fact that the high-frequency currents in fibers can be excited only when the electric field is parallel to the fibers. This study expands the design approach of flexible and intelligent-modulation MA materials for further wearable devices.