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

Abstract

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 via 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 in silico 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.