3D printing of transparent pH-mediated high-water-content hydrogels for electromagnetic interference (EMI) shielding

3D printing techniques allow for fabricating accurate structured and complex parts, designed via computer-aided design (CAD). In this research, we introduce extrusion 3D printing of optically transparent, high-water-content (96%) hydrogels toward fabrication of easy-to-make, cost-effective electromagnetic interference (EMI) shields. First, we designed polyacrylic acid soft hydrogels with different concentrations to achieve a 3D printable composition with desired rheological properties. Then, 4wt.% transparent hydrogel was printed into different structures on a cellulose acetate substrate. The 3D-printed (100% infill) hydrogels containing 96wt.% water demonstrated appreciable EMI shielding as high as 18.6 dB at a thickness of 1.6 mm. More importantly, it is shown that the 3D printing technique allows for macroscale patterning of the shields, providing more degrees of freedom in tuning the EMI shielding performance. Our achieved results validated that the 3D-printed transparent hydrogels attenuate EM waves noticeably, rendering them a superb candidate for high-performance optically transparent EMI shields.