Flexible plastic substrates are widely used in printed electronics; however, they cause major climate impacts and pose sustainability challenges. In recent years, paper-based electronics has been studied to increase the recyclability and sustainability of printed electronics. The aim of this paper is to analyze the printability and performance of metal conductor layers on different paper-based substrates using both flexography and screen printing and to compare the achieved performance with that of plastic foils. In addition, the re-pulpability potential of the used paper-based substrates is evaluated. As compared to the common polyethylene terephthalate (PET) substrate, the layer conductivity on paper-based substrates was found to be improved with both the printing methods without having a large influence on the detail rendering. This means that a certain surface roughness and porosity is needed for the improved ink transfer and optimum ink behavior on the surface of the substrate. In the case of uncoated paper-based substrates, the conductivity and print quality decreased by preventing the formation of the proper and intimate ink-substrate contact during the ink transfer. Finally, the re-pulpability trials together with layer quality analysis detected very good, coated substrate candidates for paper-based printed electronics competing with or even outperforming the print quality on the reference PET foil.

Printed, flexible, and hybrid electronic technologies are advancing rapidly leading to remarkable developments in smart wearables, intelligent textiles, and health monitoring systems. Flexible electronics are typically fabricated on petroleum‐derived polymeric substrates. However, in the light of global environmental concerns regarding fossil raw materials, there is a need to drive the production of flexible electronics devices based on sustainable materials. Additionally, there is a need to reduce the quantity of electronic waste by developing material recovery and recycling technologies. Here, a fully biobased and biodegradable substrate tailored for printed flexible electronic applications is developed. Based on a nanocomposite of cellulose nanofibril (CNF) and hydroxyethyl cellulose (HEC), the substrate shows excellent mechanical and optical properties for printed flexible electronics applications. High‐resolution screen printing of conductive ink and typical electronics assembly processes are possible to realize on the substrate. An electrocardiograph (ECG) device is fabricated on the cellulosic substrate as a technology demonstrator and its performance is confirmed on human volunteers. Last, end‐of‐life scenarios are studied for printed electronic devices where device degradation and subsequent material recovery concepts are presented. This work demonstrates that sustainable plant‐derived materials can play a big role toward a green transition in the electronics industry.

Reusable packaging has been used as a case study for development of durable and sustainable smart tags that can provide both identity management and potentially also condition monitoring capabilities. Four different smart tag technologies have been investigated, including laser engraved 2D bar codes, printed 2D bar codes with combined temperature indicator, printed NFC (Near‐Field Communication) tags and RFID (Radio Frequency Identification) tags as labels. All technologies showed excellent durability towards repeated washing and heating when protective layers were used. SWOT analysis was also carried out to weight the advantages and disadvantages of the different technologies summarizing the choice of the technology per use and end‐of‐life requirements. Sustainability of the investigated technologies is discussed from the smart tag recyclability perspective and the challenges that can be seen related to the use of electronic functionalities and/or plastic‐based protective layers.

Cortisol is involved in regulating many human physiological functions, with cortisol imbalance capable of causing adverse mental and physical health conditions. Existing tools for monitoring of cortisol can assist in alerting the need for mediation strategies, but these typically require time consuming processes such as sample preparation followed by laboratory analysis. This work demonstrates a miniature flexible sensor patch incorporating electrode structures produced by high throughput roll-to-roll rotary screen-printing process, which are subsequently functionalized by electropolymerization of a polypyrrole/Prussian blue molecularly imprinted polymer for measuring cortisol by chronoamperometry. The developed single use sensor patch provides acceptable selectivity for cortisol and operates in artificial eccrine perspiration across a broad concentration range of 0.1–10 000 ng ml⁻¹ (R ² = 0.916). In the application of measuring thermally induced sweat, the sensor provided results in agreement with the natural circadian rhythm of fluctuating cortisol.

Within the past years, there has been a growing demand for sustainable, cost-efficient on-line sensing of chemical and physical properties and locations of products. Measuring of products’ physical properties, such as temperature and humidity, could improve product safety and efficiency of logistic operations. In the future measurement of temperature of food items could also aid in reducing food wastage. The aim of this study was to calculate the life cycle environment impacts of a temperature logger, hereafter called smart label, primarily targeted for the monitoring of the packed food products. According to the results, the largest normalised impacts of the smart label production are resource use (both use of fossil fuels and use of minerals and metals), eutrophication and particulate matter formation. The main materials causing these impacts were the printed electronics inks and adhesives. In addition, energy used in the production, and plastics used as substrates had large impacts on the results. It should be noted that the present calculations have mainly been made on a laboratory scale. The impacts are likely to get smaller on an industrial scale with more efficient production. In the future, the label could potentially bring environmental benefits through product savings when used in products with high environmental load.