Fabrication of Uniform Anionic Polymeric Nanoplatelets as Building Blocks for Constructing Conductive Hydrogels with Enhancing Conductive and Mechanical Properties

Conductive hydrogels play a crucial role in advancing technologies like implantable bioelectronics and wearable electronic devices, owing to their favorable conductivity and appropriate mechanical properties. Here, a novel bottom-up approach is reported for crafting conductive nanocomposite hydrogels to achieve enhancing conductive and mechanical properties. In this approach, new poly(ɛ-caprolactone)-based block copolymers with sulfonic groups are first synthesized and self-assembled into uniform polyanionic nanoplatelets. Subsequently, these negatively charged nanoplatelets, with sulfonic groups on the surface, are employed as nanoadditives for the polymerization of 3,4-ethylenedioxythiophene (EDOT), resulting in poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/nanoplatelet complex with 3.8 times enhanced electrical conductivity compared with their counterparts prepared using block copolymers (BCPs). Blending the (PEDOT:PSS)/nanoplatelet complex with calcium alginate, nanocomposite hydrogels are successfully prepared. In comparison with hydrogels with (PEDOT:PSS)/BCP complexes prepared by a top-down method, the nanocomposite hydrogels are found to show twice as strong mechanical strength and 1.6 times higher conductivity. This work provides valuable insights into the bottom-up construction of conductive hydrogels for bioelectronics using well-controlled polymeric nanoplatelets.