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This literature survey, conducted by the Digital Cellulose Center, details sensors and energy harvesting technologies capable of being integrated in, or on, cellulose-based materials such as paper or board. The goal of the survey is to identify how full sensor system integration can be performed on environmentally friendly substrates. Using cellulose and other bio-based materials from the forest is a promising way of making electronics greener. Also, such system integration can add new intelligence to existing cellulose products such as packages for food and logistics. The survey focuses on moisture sensors, temperature sensors, pressure and strain sensors, piezoelectric cellulose, patterning methods, and triboelectric nanogenerators, each one divided into separate chapters. The outcome of the survey is considered in the light of connected cellulose-based sensor applications, identifying the most pertinent scientific questions and remaining challenges. We particularly consider the results in light of sensors integrated into pressboard.

Over the past 150 years, our ability to produce and transform engineered materials has been responsible for our current high standards of living, especially in developed economies. However, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of the economy, energy, and climate. We are at the point where something must drastically change, and it must change now. We must create more sustainable materials alternatives using natural raw materials and inspiration from nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments (LCAs) based on reliable and relevant data to quantify sustainability. We need to seriously start thinking of where our future materials will come from and how could we track them, given that we are confronted with resource scarcity and geographical constrains. This is particularly important for the development of new and sustainable energy technologies, key to our transition to net zero. Currently ‘critical materials’ are central components of sustainable energy systems because they are the best performing. A few examples include the permanent magnets based on rare earth metals (Dy, Nd, Pr) used in wind turbines, Li and Co in Li-ion batteries, Pt and Ir in fuel cells and electrolysers, Si in solar cells just to mention a few. These materials are classified as ‘critical’ by the European Union and Department of Energy. Except in sustainable energy, materials are also key components in packaging, construction, and textile industry along with many other industrial sectors. This roadmap authored by prominent researchers working across disciplines in the very important field of sustainable materials is intended to highlight the outstanding issues that must be addressed and provide an insight into the pathways towards solving them adopted by the sustainable materials community. In compiling this roadmap, we hope to aid the development of the wider sustainable materials research community, providing a guide for academia, industry, government, and funding agencies in this critically important and rapidly developing research space which is key to future sustainability., The authors would like to thank The Faraday Institution ReLiB Project Grant Numbers FIRG005 and FIRG006, the UKRI Interdisciplinary Circular Economy Centre for Technology Metals (Met4Tech) Grant No. EP/V011855/1 and the EPSRC Critical Elements and Materials Network (CREAM) EP/R020140/1 for providing financial assistance for this research.