Periodic Reporting for period 2 - REFORM (PRINTED ELECTRONICS FOR THE CIRCULAR ECONOMY)
Okres sprawozdawczy: 2024-01-01 do 2024-12-31
Functional Electronics,is a key enabler of European digital transformation. It supports many key enabling technology breakthroughs and will play a major role in the transition to a circular economy. The total market for printed, flexible, and organic electronics is expected to grow to $74 billion by 2030 (IDTechEx Research). However, these opportunities are threatened by the environmental impact of electronic devices.
Electrical and electronic waste (e-waste) is one of the fastest-growing waste streams, with 54 million metric tons generated worldwide in 2019. Only around 20–25% is formally recycled. Europe leads the world in e-waste generation per capita. If Europe is to lead in functional electronics, we must also prevent them from becoming a future e-waste problem.
REFORM addresses the sustainability challenges around conventional surface mounted and embedded functional electronics and aims to accelerate the development of a new European green functional electronics supply chain. It seeks to use ecodesign principles to ensure that functional electronics can meet multiple application requirements for technological performance and compliance, while also meeting societal and environmental needs for sustainability.
REFORM aims to develop environmentally benign electronic 'building blocks' focusing on green, bio-derived adhesives, conductive inks and flexible substrates. Among them REFORM sets out to create bio-based de-bondable adhesives to separate electronics components on demand for recycling, a suite of sustainable fully-organic conductive inks for use in printed flexible electronics and scalable production of flexible substrates from renewable sources that satisfy printability and performance for various applications. These will be integrated into industry-led functional electronics systems and supported by innovations in conformance testing and material recovery methods, helping meet the ambitions for the European Green Deal. The immediate outcome of REFORM will be three demonstrators: a green smart logistics tag, a green embedded wireless sensor and a microsupercapacitor, taking the project from TRL 2/3 to TRL 5.
Electrical and electronic waste (e-waste) is one of the fastest-growing waste streams, with 54 million metric tons generated worldwide in 2019. Only around 20–25% is formally recycled. Europe leads the world in e-waste generation per capita. If Europe is to lead in functional electronics, we must also prevent them from becoming a future e-waste problem.
REFORM addresses the sustainability challenges around conventional surface mounted and embedded functional electronics and aims to accelerate the development of a new European green functional electronics supply chain. It seeks to use ecodesign principles to ensure that functional electronics can meet multiple application requirements for technological performance and compliance, while also meeting societal and environmental needs for sustainability.
REFORM aims to develop environmentally benign electronic 'building blocks' focusing on green, bio-derived adhesives, conductive inks and flexible substrates. Among them REFORM sets out to create bio-based de-bondable adhesives to separate electronics components on demand for recycling, a suite of sustainable fully-organic conductive inks for use in printed flexible electronics and scalable production of flexible substrates from renewable sources that satisfy printability and performance for various applications. These will be integrated into industry-led functional electronics systems and supported by innovations in conformance testing and material recovery methods, helping meet the ambitions for the European Green Deal. The immediate outcome of REFORM will be three demonstrators: a green smart logistics tag, a green embedded wireless sensor and a microsupercapacitor, taking the project from TRL 2/3 to TRL 5.
Within the second period technical activities focused mainly on starting to build the functional electronics systems using the building blocks developed in the project. As a result, the feasibility of these building blocks has been continuously assessed and optimized to make them more suitable for three Use Cases.
The main achievements in the building blocks are:
- Development of highly conductive metal-free water-based inks with optimized conductivity and adjustable viscosity to ensure high stability and printability by both 3D printing and screen printing, suitable for all the three use cases.
- Development of cutting-edge substrates utilizing mixtures of cellulose with conventional eucalyptus fibres that require no coating or planarization layer, and the continuation of optimizations for the forming of and recycling of thermosetting substrates. The scaling up of the processes for forming both types of substrates was also optimized and the planarization of delignified wood foils was also demonstrated.
- Synthesis of various bio-based epoxy and hardener, some of them containing reversible bond, to develop bio-based and de-bondable adhesives and evaluation of different approaches for the formulation of the electronic grade de-bondable adhesives.
These building blocks have been implemented in our target use cases during this period, in which printed strain gauges and RFID smart labels were tested, with improvements made to enhance ink and material compatibility. Assembled samples obtained response in far field environment, and NFC signal transmission through pressure vessel materials has been tested.
The materials developed within the project have been evaluated by continuous sorting/mechanical recycling tests, metal biorecovery has been tested using acidophilic bacteria and initial LCIA models for project products have been carried out.
The main achievements in the building blocks are:
- Development of highly conductive metal-free water-based inks with optimized conductivity and adjustable viscosity to ensure high stability and printability by both 3D printing and screen printing, suitable for all the three use cases.
- Development of cutting-edge substrates utilizing mixtures of cellulose with conventional eucalyptus fibres that require no coating or planarization layer, and the continuation of optimizations for the forming of and recycling of thermosetting substrates. The scaling up of the processes for forming both types of substrates was also optimized and the planarization of delignified wood foils was also demonstrated.
- Synthesis of various bio-based epoxy and hardener, some of them containing reversible bond, to develop bio-based and de-bondable adhesives and evaluation of different approaches for the formulation of the electronic grade de-bondable adhesives.
These building blocks have been implemented in our target use cases during this period, in which printed strain gauges and RFID smart labels were tested, with improvements made to enhance ink and material compatibility. Assembled samples obtained response in far field environment, and NFC signal transmission through pressure vessel materials has been tested.
The materials developed within the project have been evaluated by continuous sorting/mechanical recycling tests, metal biorecovery has been tested using acidophilic bacteria and initial LCIA models for project products have been carried out.
The results obtained represent a significant advancement:
•Scalable fabrication of reliable sustainable all-carbon inks enabling 3D/screen printing of large-scale electronic devices.
•Sinter-free inks with good adhesion on various paper substrates, and “simultaneously” high electrical conductivity
•Cellulose-based coatings that can be applied to commercially available paper and wood-based foils developed during the project. By combining different cellulose types the mechanical properties are enhanced, addressing the drawbacks of the CNC-based coatings reported in literature (i.e. brittle and "plastified" layers). The water barrier properties of these coatings have also been demonstrated being 10 times higher than the reference values for WVTR for PE or PC films.
• A new approach is currently being evaluated, which involves mechanical treatment of the surface to improve the printability of functional inks. Additionally, it was demonstrated that unbleached fibres can also be used to form paper substrates compatible with printed electronics. This will represent a relevant steppingstone in further reducing the costs of these substrates when considering scaled or industrial production.
•Wood-based substrates: Green chemistry methods are being introduced to delignify balsa and birch wood. These methods involve low-temperature processes, which include a hot press step. The mechanical properties of the hot-processed samples are similar to those of the original untreated wood samples. These samples were coated with a cellulose-based coating to achieve RMS roughness compatible with printing silver inks, allowing for conductivity similar to that obtained in paper or thermosetting substrates.
•Recyclable thermosetting substrates: thermosetting epoxy substrates with 3R technology (recyclable, repairable and reprocessable), with the capability of being printed with functional inks (PEDOT based inks already tested). Recyclability of the thermosettable resin was confirmed.
•Synthesis of new bio-based and reversible epoxy resin and synthesis of new bio-based and reversible hardener.
•Demonstration of 1-pack electrically conductive microelectronic adhesives built upon reversible and bio-based epoxy resins. Demonstration of successful separation of substrate from bonded component (debonding) by leveraging the inbuilt chemical reversibility.
•Demonstration of silver recovery from 1-pack electrically conductive microelectronic adhesives by chemical dissolution of the adhesive binder.
•Fully-printed microsupercapacitors with areal capacitance surpassing 50 mF/cm^2 at high scale rate of 1 V/s. Fully printed large-scale on-paper MSC arrays comprising up to 100 cells with charging rate up to 30 V/s and working voltage window up to 160 V. The overall capacitance is about 3 µF, one order of magnitude larger than the state-of-the-art value published in the literature.
•Scalable fabrication of reliable sustainable all-carbon inks enabling 3D/screen printing of large-scale electronic devices.
•Sinter-free inks with good adhesion on various paper substrates, and “simultaneously” high electrical conductivity
•Cellulose-based coatings that can be applied to commercially available paper and wood-based foils developed during the project. By combining different cellulose types the mechanical properties are enhanced, addressing the drawbacks of the CNC-based coatings reported in literature (i.e. brittle and "plastified" layers). The water barrier properties of these coatings have also been demonstrated being 10 times higher than the reference values for WVTR for PE or PC films.
• A new approach is currently being evaluated, which involves mechanical treatment of the surface to improve the printability of functional inks. Additionally, it was demonstrated that unbleached fibres can also be used to form paper substrates compatible with printed electronics. This will represent a relevant steppingstone in further reducing the costs of these substrates when considering scaled or industrial production.
•Wood-based substrates: Green chemistry methods are being introduced to delignify balsa and birch wood. These methods involve low-temperature processes, which include a hot press step. The mechanical properties of the hot-processed samples are similar to those of the original untreated wood samples. These samples were coated with a cellulose-based coating to achieve RMS roughness compatible with printing silver inks, allowing for conductivity similar to that obtained in paper or thermosetting substrates.
•Recyclable thermosetting substrates: thermosetting epoxy substrates with 3R technology (recyclable, repairable and reprocessable), with the capability of being printed with functional inks (PEDOT based inks already tested). Recyclability of the thermosettable resin was confirmed.
•Synthesis of new bio-based and reversible epoxy resin and synthesis of new bio-based and reversible hardener.
•Demonstration of 1-pack electrically conductive microelectronic adhesives built upon reversible and bio-based epoxy resins. Demonstration of successful separation of substrate from bonded component (debonding) by leveraging the inbuilt chemical reversibility.
•Demonstration of silver recovery from 1-pack electrically conductive microelectronic adhesives by chemical dissolution of the adhesive binder.
•Fully-printed microsupercapacitors with areal capacitance surpassing 50 mF/cm^2 at high scale rate of 1 V/s. Fully printed large-scale on-paper MSC arrays comprising up to 100 cells with charging rate up to 30 V/s and working voltage window up to 160 V. The overall capacitance is about 3 µF, one order of magnitude larger than the state-of-the-art value published in the literature.