Ecological, flexible and transparent cellulose-based substrates without post-production treatment for organic electronic devices

Abstract

In the past few decades, technological advances have aroused the interest of industries and consumers for flexible electronic devices. However, the substrates currently used, such as glass and polyethylene terephthalate (PET), present problems regarding their performance and destination, since the first is difficult to handle and the second comes from non-renewable sources. Common properties required in substrates to provide their use in organic electronics are flexibility, stability and sufficient transparency. Therefore, as a sustainable and efficient alternative, the present study aimed to develop a totally cellulose-based substrate, a natural abundant polymer that presents thermal stability, mechanical strength, recyclability and is biodegradable. Different substrates were produced using microfibrils from Eucalyptus sp. A pure microfiber substrate weighing 25 g m−2 was obtained by the vacuum filtration method and paper-forming machine. The other four substrates were obtained by the casting method containing cellulose acetate matrix and freeze-dried microfibrils reinforcement at different concentrations. In addition, a substrate containing 1.0% of the suspended microfibrils as reinforcement in the cellulose acetate matrix was produced. A conductive thin film of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) was deposited by air-brush technique as an electrode to evaluate the electrical performance of the substrates. The obtained films were characterized by their optical, thermal and morphological properties, showing a great potential to be used as substrate in organic electronic devices, being applied for an ethanol gas sensor device.