• Coclite, Anna Maria
• Muralter, Fabian

Abstract

<jats:title>Abstract</jats:title><jats:p>In this study, a novel, fully polymeric setup for piezoresistive sensing is prepared and tested. Monolayers of polystyrene (PS) nanospheres are assembled on flexible polyethylene naphthalate substrates. Subsequently, thin layers (≈50–100 nm) of poly(3,4‐ethylenedioxythiophene) (PEDOT) are deposited conformally around the spheres by oxidative chemical vapor deposition (oCVD). Voltage−current characteristics and direct resistance measurements are performed to test the electrical properties of the samples in their unstrained state and their piezoresistive response during bending. Substrate deposition temperature (<jats:italic>T</jats:italic><jats:sub>sub</jats:sub>) and film thickness (<jats:italic>t</jats:italic><jats:sub>PEDOT</jats:sub>) are used as parameters to alter properties of the PEDOT thin films; increased <jats:italic>T</jats:italic><jats:sub>sub</jats:sub> and <jats:italic>t</jats:italic><jats:sub>PEDOT</jats:sub> lead to samples exhibiting lower intrinsic resistance. The electrical conductivity of the samples is estimated to range as high as tens of S cm<jats:sup>−1</jats:sup>. Dopant exchange of the oCVD‐PEDOT layer (intrinsically, chlorine‐doped) is performed by putting the samples in 0.5 <jats:sc>m</jats:sc> sulfuric acid, which decreases their resistance by ≈1/3. Regarding the piezoresistive properties of the devices, acid treatment, higher <jats:italic>T</jats:italic><jats:sub>sub</jats:sub> and <jats:italic>t</jats:italic><jats:sub>PEDOT</jats:sub> (thus, lower intrinsic resistance) yield samples with increased response. As a result, gauge factors as high as 11.4 are achieved. Due to their flexibility and low‐cost, the proposed structures can be readily employed as skin‐inspired or wearable electronic devices.</jats:p>

Topics

• impedance spectroscopy
• surface
• polymer
• thin film
• electrical conductivity
• chemical vapor deposition