One-step assembly of conductive coatings from polyphenol and Nanocarbon-PIL: A versatile approach for fabricating multifunctional sensors

A highly conductive strategy for even coating carbon nanomaterials is in great demand for various applications. We introduce a conductive modification technique that is universally applicable to a range of substrates. It involves enhancing surface electronegativity by dip-coating various substrates with tannic acid (TA) and ferric chloride (FeCl 3 ) solutions. The process was further refined by the ability of imidazolyl poly (ionic liquid) (PIL-Cl) to disperse carbon black (CB) in water. The conductive modification of various substrate surfaces was facilitated based on electrostatic interactions between the TA-Fe 3+ coating and the CB-(PIL-Cl) dispersion. Meanwhile, to demonstrate the potential of this approach in fabricating materials for wearable sensors, we have fabricated conductive PET fabrics (PTFA@CB). These PTFA@CB fabrics serve as strain sensors, capable of tracking human movement. Additionally, the multi-layer fabric stack design can function as a pressure sensor, providing feedback on pressure coordinates and detecting gripping motions. In addition, the TA-Fe 3+ coating makes PTFA@CB significantly hydrophilic, which improves their responsiveness to humidity. The method described in this paper can be extended to deposit carbon nanomaterials onto various substrates with diverse shapes and properties. The process we developed offers a simple, convenient, and environmentally friendly approach for preparing conductive substrates, with the potential for scalable production.