Polimerización en fase de vapor de polímeros conductores en hidrogeles de nanofibrillas de celulosa para formar...

Conducting polymers are essential for soft bioelectronics, but they are challenging to process into homogeneous, low-solidity hydrogels due to their poor solubility and tendency to agglomerate. Here, we utilize cellulose nanofibril (CNF) hydrogels as a percolating template for the vapor-phase assisted polymerization of conducting polymers. Pyrrole efficiently polymerizes within the hydrated CNF network, forming a conformal polypyrrole (PPy) coating that yields conductivities approaching 100 S/m and charge storage of 16 mAh/g (dry) or capacitance of 52 F/g solids at 93 wt% water content. The CNF framework induces rod-like percolation of the PPy phase, producing unusually low percolation thresholds and non-universal transport exponents. Long-aspect-ratio fibrils further enhance conductivity by increasing the number of effective junctions, and PPy stiffens the hydrogels (0.2-1.5 MPa) by locking these junctions. Glycerol could be used as the liquid phase to prevent evaporation and these gels remained conductive and dimensionally stable in air. Comparison with liquid-phase polymerization highlights that vapor delivery minimizes skin formation and enables more uniform bulk coverage. Finally, we demonstrate 2D/3D patterning and conductive filament fabrication, underscoring vapor-phase polymerization as a versatile route for soft conducting materials, electrodes, and patterned hydrogel devices.