Mechanistic insight into RCNs-induced conductivity enhancement in sustainable CWPU/PEDOT:PSS nanocomposites for flexible and biocompatible electronics

We report a sustainable and fully bio-derived nanocomposite system composed of castor oil-based anionic waterborne polyurethane (CWPU), regenerated cellulose nanoparticles (RCNs), and PEDOT:PSS, designed for flexible electronic applications. Rather than achieving high absolute conductivity, this work demonstrates a significant enhancement in electrical conductivity, achieved without metal-based dopants or inorganic additives, through structural modulation within an all-organic matrix. Mechanistically, RCNs act as functional phase modulators that selectively interact with the PSS component of PEDOT:PSS <i>via</i> hydrogen bonding. This interaction promotes partial phase separation, enabling the formation of PEDOT-rich domains and enhancing chain alignment and charge transport pathways. The proposed mechanism captures the transition from a homogeneous dispersion to a structurally reorganized conductive network during film formation. Experimental evidence from AFM, Raman spectroscopy, and conductivity analysis supports this model, while <i>in silico</i> docking reveals potential biocompatibility advantages of PEDOT through interactions with fibronectin domains. This study highlights a rare case in which conductivity enhancement is achieved solely through the rational assembly of bio-based organic materials, offering a new strategy for sustainable and metal-free electronic materials.