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Printed piezoresistive strain sensors based on stretchable roll-to-roll screen-printed silver electrodes on polydimethylsiloxane substrates and inkjet-deposited single-wall carbon nanotube micropatterns are demonstrated in this work. With the optimization of surface wetting and inkjet printing parameters, well-defined microscopic line patterns of the nanotubes with a sheet resistance of

The increasing need for wearable electrophysiological monitoring devices has motivated significant amount of research to develop electronic tattoos (e-tattoo) enabling high comfortability and unobtrusive usage. Despite considerable advancements, challenges still remain that limit the device testing under clinical settings and consequently, the uptake to practical usage. A key challenge is the robust full signal pathway from the skin to the electronics device. Another factor limiting the concept testing with high number of test devices is the lack for scalable materials and processes comprising all manufacturing steps. The study presents a scalable manufacturing of self-adhering tattoo electrodes and interconnects on transferable breathable polydimethylsiloxane (PDMS) substrate with the thickness of 30 µm. Transfer tattoo enables two-sided signal pathway from the skin, in to the encapsulated conductor traces and provides exposed connection points to electronics. The e-tattoos withstand repeated one thousand, 10% elongation cycles and the transfer substrate showed breathability comparable to commercial medical patches. The integration of flexible wireless ECG module with the skin-mounted e-tattoo is also demonstrated. The results enable the up-scaled fabrication of robust e-tattoos with integrated electronic modules that is prerequisite for the scientific studies relying on high number of test devices and industrial uptake of e-tattoo concepts.

Lack of functional integration and high manufacturing costs have been identified as major challenges in commercialization of point-of-care devices. In this study, roll-to-roll (R2R) fabrication process was developed for large-scale manufacturing of disposable microfluidic devices. The integrated, user-friendly device included a plasma separation membrane for simple blood filtration, immobilized antibodies for specific immunodetection, microfluidics for plasma transport and reagent mixing, and a blister for actuation and waste storage. These functionalities were designed to be compatible with R2R processing, which was demonstrated using pilot-scale printing lines producing 60 devices in an hour. The produced sensors enabled rapid (10 min) and sensitive (2 μg/mL) fluorescence-based immunodetection of C-reactive protein from 20 μL of whole blood.

Stretchable electronics has attracted much interest recently because of its potential applications in the area of wearable electronics and healthcare. Highly elastic polydimethyl siloxane (PDMS) has been for decades a widely used material in prototyping purposes. It enables the realization of a variety of mechanical and optical functions besides being a substrate for other processes or applications. As a substrate, PDMS enables high stretchability and easy integration of other parts made of PDMS. In this work, we demonstrated a high-volume production of stretchable electrical interconnections on PDMS substrates. We used roll-to-roll (R2R) rotary screen printing that has been conventionally applied in high-throughput fabrication of electronics on flexible, but not stretchable, substrates. We demonstrated silver interconnects whose conductivity remains sufficient for signal transmission, for example, in sensor structures under repeated 20% strain over 100 cycles. We also demonstrated R2R compatible PDMS encapsulation of electrical interconnections that increased the strain repetition durability by a factor of 2.

Flexible electrodes are crucial for the growth of modern flexible electronics or smart clothing. Their ability to serve as sensing elements, deliver energy or transmit electrical signals in different conditions is essential for the evolution of wearables that will enrich our everyday life. In this study, we focus our efforts on understanding the impact of an additional protective layer on elongated and washed roll-to-roll printed (R2R) conductive flexible electrodes of various shapes. The electrical and morphological examinations provide information on the performance of the electrodes and materials during washing and elongation cycles. The acquired results indicate propitious electrode shapes as well as data concerning micro-scale cracking mechanisms, which are responsible for electrode performance degradation. The application of commercially available pastes and R2R printing methods allow the flawless utilization of the results and the fabrication of flexible and more reliable electronic components.

Method for roll-to-roll imprinting of components, in which method an imprint resist material layer (5) is applied on a substrate material layer (1) before imprinting the resist layer with a roll mold (3), wherein the imprint resist material (5) is applied on the substrate material layer (1) so, that the imprint resist material layer extends over the side edges of the substrate material layer and on the opposite side of the substrate material layer in relation to the imprinting surface of the substrate material layer in the cross-section of the substrate material layer together with the applied imprint resist material layer.Patent family as of 27.12.2021EP3894955 A1 20211020 EP20190821267 20191209 FI128257 B 20200131 FI20180006077 20181214 FI20186077 A 20200131 FI20180006077 20181214 WO20120836 A1 20200618 WO2019FI50877 20191209Link to currentpatent family on right

Conformable electrodes are essential for the development of flexible electronics or functional clothing, regardless of their application. Their reliable ability to transfer electric signals or serve as sensing elements in various conditions is vital for the advancement of wearables that will enhance our everyday life. In this research, we concentrate our efforts on the understanding of the influence of elongation and washing on roll-to-roll printed conductive electrodes of various shapes and materials. A large sample set provides data on the breaking mechanisms and how these affect the electrical properties of the electrodes. In addition, the physicochemical analysis offers insights into the electrodes’ and materials’ behavior in extreme conditions during elongation and washing cycles. The achieved results indicate auspicious nanoparticle shapes and sizes as well as evidence regarding micro-scale breaking mechanisms responsible for electrodes degradation. Utilization of commercially available materials and roll-to-roll printing techniques allow the seamless application of achieved results and the creation of more reliable, flexible electronic devices.

Microfluidic-based integrated molecular diagnostic systems, which are automated, sensitive, specific, user-friendly, robust, rapid, easy-to-use, and portable, can revolutionize future medicine. Current research and development largely relies on polydimethylsiloxane (PDMS) to fabricate microfluidic devices. Since the transition from the proof-of-principle phase to clinical studies requires a vast number of integrated microfluidic devices, there is a need for a high-volume manufacturing method of silicone-based microfluidics. Here we present the first roll-to-roll (R2R) thermal imprinting method to fabricate integrated PDMS-paper microfluidics for molecular diagnostics, which allows production of tens of thousands of replicates in an hour. In order to validate the replicated molecular diagnostic platforms, on-chip amplification of viral ribonucleic acid (RNA) with loop-mediated isothermal amplification (LAMP) was demonstrated. These low-cost, rapid and accurate molecular diagnostic platforms will generate a wide range of applications in preventive personalized medicine, global healthcare, agriculture, food, environment, water monitoring, and global biosecurity.

Several lab-on-chip prototypes rely on PDMS (polydimethylsiloxane) processed with laborious lithographic techniques. Upscaling the manufacturing volumes requires typically material change which increases the market entry time and costs. As a solution, a novel, high-volume fabrication method called Roll-to-Roll PDMS thermal imprinting is presented. This study demonstrates high accuracy and high volume (480 chips/h) replication of microwells for single cell RNA sequencing (Seq-Well). Sealing of these devices with semipermeable membrane followed by lysis of compartmentalized human cells is further shown.

Industrially scalable and roll-to-roll-compatible fabrication methods are utilized to fabricate high-mobility (≈8 cm(2) V(-1) s(-1) ) nanocrystalline In2 O3 thin-film transistors (TFTs) on an flexible plastic substrate. Flexographic printing of multiple thin In2 O3 semiconductor layers from precursor-solution is performed on a Al2 O3 gate dielectric obtained via atomic layer deposition. A low-temperature post-contact-annealing step allows control of the TFT device turn-on voltage to ≈0 V for enhancement-mode operation.

A novel microelectromechanical-systems (MEMS)-controlled paper-like transmissive flexible display device was modeled by a combination of a cantilever with a flat plate and was realized by roll-to-roll printing process for the first time. This model provides predictions as well as improvement suggestions to both mechanical and electrical designs. A newly developed roll-to-roll printing process which was composed of flexography, gravure, lift-off, and lamination techniques used to manufacture this device was proved applicable on flexible electronics with high-volume, low-cost, and large-area solutions. This 20 V-driven device provided distinguishable three primary colors with averaged transmittance of 50% in visible region for full color flexible display applications and showed commercialization compatibility. Its electrical, mechanical, and optical characteristics excelled previous similar works. The proved major advantages of mechanical reliability, low operation voltage, and process simplicity done by this work made the MEMS flexible display an important alternative to electrophoretic, electrowetting, and electrochromic systems.

This paper focuses on ultra-violet (UV)-curing of solution-processed metal-oxide (MO) semiconductors for application in thin film transistors (TFTs). The goal is to combine low-temperature thermal annealing with UV exposure and achieve printable transistors on flexible plastic substrates. In this paper we focus on the use of two different wavelengths of UV and clarify their effect on the performance of the metal-oxide semiconductors. The electrical properties of TFTs made with these semiconductors are characterized. The results show that wavelength of the UV exposure is critical for optimized performance of the semiconductor and the TFTs.

A novel electrode patterning technique by using lift-off a sacrificial black ink layer on thin polymer substrate was performed on a roll-to-roll (reel-to-reel, R2R) printing system. An active-matrix display array was demonstrated by this technique with 2000@mm display pixels with concept of MEMS (micro electro mechanical system) etalon. The resolution of this flexography lift-off system was improved to 100@mm for pattern isolation from gravure printing. Compare to well-developed hot embossing or laser ablation for polymer substrate's patterning, R2R lift-off provides a flat and smooth surface which is a must for multilayer stacking and reliability. This system also provides a high pattern integrity, low cost, large scale, and high throughput solution for electrode patterning on flexible polymer substrate.

A 50% reduction of operation voltage improvement was achieved on a non self-emissive color filter pixels based on MEMS (micro electro mechanical system) Fabry-Perot interference device by minimizing its Newton's rings' size. Newly designed air grooves in spacer layer were proved to be efficient to evacuate air trapped inside pixels which in turn effectively lowered its operation voltage. A seesaw effect was also found if air groove occupied too large area which degrades the operation voltage lowering benefit.

As the population in Europe and many other industrial countries ages, applications of biosensors in health care close to the patient, i.e. at the point-of-care, and especially biomolecular diagnostics, become increasingly attractive to improve the quality of life of the patients and reduce the financial load on health care systems. The need to develop rapid and reliable diagnostic sensors for healthcare applications is therefore apparent. To meet these new criteria, new volume-scale capable manufacturing techniques are required for production of sensitive and reliable biosensors. The research efforts to achieve wide employment of biosensors are mainly geared toward biochips relying on conventional detection techniques, such as electrochemical and fluorescence detection. The integration of biomolecular components, nanotechnology-based transducer systems and low-cost mass-manufactured polymer fluidic and optical microsystems is one of the key issues to reduce unit costs sufficiently for widespread and ubiquitous employment of biosensors. The overall market for biochips in medical diagnostics constitutes one of the fastest emerging technology markets in the health care sector, with annual growth rates predicted to be above 25%. This growth scenario, however, requires the availability of fast, cost effective, yet sensitive and label-free, diagnostic platforms and biomolecular multiparameter tests, which can be applied for diagnosis close to the patient. Recent developments of hot embossed microfluidics, has made it possible to fabricate functional components by roll-to-roll techniques. In this presentation, we show our current achievements for manufacturing low cost immunosensors for pointof- care and home care applications.

We propose a combined far ultraviolet (FUV) and thermal annealing method of metal-nitrate-based precursor solutions that allows efficient conversion of the precursor to metal-oxide semiconductor (indium zinc oxide, IZO, and indium oxide, In2O3) both at low-temperature and in short processing time. The combined annealing method enables a reduction of more than 100 °C in annealing temperature when compared to thermally annealed reference thin-film transistor (TFT) devices of similar performance. Amorphous IZO films annealed at 250 °C with FUV for 5 min yield enhancement-mode TFTs with saturation mobility of ∼1 cm2/(V·s). Amorphous In2O3 films annealed for 15 min with FUV at temperatures of 180 °C and 200 °C yield TFTs with low-hysteresis and saturation mobility of 3.2 cm2/(V·s) and 7.5 cm2/(V·s), respectively. The precursor condensation process is clarified with x-ray photoelectron spectroscopy measurements. Introducing the FUV irradiation at 160 nm expedites the condensation process via in situ hydroxyl radical generation that results in the rapid formation of a continuous metal-oxygen-metal structure in the film. The results of this paper are relevant in order to upscale printed electronics fabrication to production-scale roll-to-roll environments.

Novel electrode patterning techniques on thin polymer substrates were developed on a roll-to-roll (reel-to-reel, R2R) printing system. Hot embossing, laser ablation, and lift-off processes were evaluated for mass production for active-matrix display arrays with 1000 µm display pixels by using the concept of micro electro mechanical system (MEMS) Fabry–Perot etalon. Among which, the newly developed lift-off flexography process provided the best pattern integrity with 100 µm resolution. The demonstrator of display array proved R2R printing system's possibility and capability under 1 m/s speed. A complete multilayer stack demonstration with alignment process also indicated its variable application. Further actuation for the MEMS display proved the robustness of device made by printing techniques.

Traditionally, the primary function of printing has been the delivery of data and information for visual inspection and further interpretation by humans or machines. The advantage of printing is that it enables cost efficient mass manufacturing of electronics and other functionalities on large and flexible substrates like plastic, paper and fabrics. New printable functional materials, print production processes and reading mechanisms are expanding the role and function of printing toward printed intelligence. This is the opportunity gap between traditional paper, packaging and printing industry products and ICT/electronics industry products and can be realised for example as disposable sensors, simple 'electronic' components and circuits, large area functional paper like intelligent products, smart packages, etc.Ageing population in Europe will increasingly burden the health care system, e.g. chronic diseases are becoming more and more common and are influencing the quality of life of rapidly increasing number of people. New solutions for low cost and distributed biomolecular recognition measurements are required to reduce the number of costly laboratory tests, hospital controls and idle visits to general practices.Recent developments of hot embossed microfluidics and optics, has made it possible to fabricate functional components by roll-to-roll techniques. In this presentation, we show our current achievements for manufacturing low cost immunosensors for point-of-care and home care applications through examples of microfluidic and optical structures.

In this presentation, we discuss opportunities of novel substrate materials for roll-to-roll (R2R) printed and hybrid electronics and diagnostics applications as well as future productions aspects. Traditionally standard substrates have been PET, PEN, PC, PMMA etc or stretchable polyurethane films. However, application requirements, especially wearable electronics and diagnostics, and sustainability issues are setting new demands for the future. Firstly, we present R2R thermal imprinting method to fabricate integrated polydimethylsiloxane (PDMS)-paper micro-fluidics for molecular diagnostics, which demonstrated in on-chip amplification of viral ribonucleic acid (RNA) with loop-mediated isothermal amplification (LAMP). Secondly, we discuss about new bio-based and recycled materials that include introduction of novel interactive cellulose fibre acoustic RGB-LED panel that is manufactured using R2R printing, chip assembly and foam forming technique. Moreover, to improve the sustainability, performance and consumer acceptance of printed and hybrid electronics we will introduce these functionalities on recycled, bio-based and biodegradable substrates and compare their functionality against traditional PET/PEN substrates. Third part of the presentation introduces PrintoNode industrial internet platform, which has been ramped-up recently. The aim of the PrintoNode is to explore challenges and solutions how to utilize collected process data in printed and hybrid electronics manufacturing and product lifetime towards novel data based business models.

We demonstrated the possibility of using roll-to-roll mass production techniques like gravure printing, hot embossing, and lamination for MEMS (Micro Electro Mechanical System) Fabry-Pérot display pixel. Integration of printing process was raised and demonstrated. Preliminary structural demonstration of integrated MEMS display pixel made by low cost, high throughput, and easy process printing techniques on flexible substrate was proved.Hot embossing results show good 100 μm-wide electrode isolation on highly amorphous polymer (cellulose acetate, CA) substrate while highly crystalline polymer (polyethyline naphthalate, PEN) shows its stiffness and robustness under high temperature. Structure sizes ranging from 50 to 300 μm with heights ranging from 1 to 15 μm were successfully gravure printed on Al coated PEN substrate with wetting options. Lamination process of 16 μm-thick PEN on 125 μm-thick PEN with gravure printed spacers in between proved easy, simple roll-to-roll process capability for large area display devices.

Printed and organic electronics are expected to grow a remarkable business of 250 – 300 billion USD in 20 years. When aiming to real mass volume markets like consumer packages, continuously running, roll-to-roll processes with high throughput capability are in key role. For example processing and fabrication of organic light-emitting devices and solar cells are nowadays carried out using traditional techniques such as spin coating and vacuum thermal deposition. However, these techniques have several disadvantages, e.g. material wastage and they are time consuming, and therefore, tremendous benefits are gained by incorporating roll-to-roll capable techniques, such as gravure printing and hot-embossing. In this presentation we show current status of roll-to-roll manufacturing of OLEDs, organic solar cells, diffractive gratings and lightguides.