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The demand for flexible and stretchable devices has been increasing in multiple fields, such as healthcare, energy harvesting, and artificial intelligence. In this study, we report a novel method to fabricate flexible and stretchable devices by integrating a kirigami sheet with an elastomer, both stretchable. Owing to the flatness of the kirigami sheet under no stress, electrodes can be patterned using a printing technique, which can enable large size and mass production. Kirigami sheets form three-dimensional shapes under stress/strain. The integration of kirigami and elastomers is carried out by placing a liquid elastomer on the three-dimensional structure. A biaxially stretchable light-emitting device was fabricated by patterning the electrode on a kirigami sheet and placing a light-emitting elastomer on top of it. This study reports the fabrication method, fabricated device on activation, and stretchability. [ABSTRACT FROM AUTHOR]

Flexible devices have been studied to realize IoT or novel wearable devices. The data that flexible devices deal with can include personal information when application areas further expand. A security system for flexible devices becomes more important in this case. In this study, we investigate the thermal stability of an organic flexible security system. The security system utilizes fabrication variation of a chip, and it is called a physically unclonable function (PUF). As a result, the bit error rate of the organic PUF is 1.8% and the index of ID uniqueness (i.e., randomness) has an almost theoretical value of 0.48. The generated ID remains even after annealing at 100 °C for 97 h by using CYTOP encapsulation. X-ray diffraction measurement implies that degradation of PUF characteristics partially derives from structure changes of the organic n-type semiconductor thin film after annealing. [ABSTRACT FROM AUTHOR]

Currently, electronic components having wavy structures are being actively studied because such wavy structures exhibit stretchability through flattening under stretching. The buckling of a thin film on an elastomer is an easy and inexpensive approach of creating a wavy structure and has attracted considerable attention. Despite its simplicity and easiness, the requirement of stretchers during film deposition limits fabrication methods, such as spin-coating and printing methods, and hinders their application in industry. Here, we eliminated the requirement of stretchers during film deposition by utilizing plastic deformation of the thin film and extending methods of developing a wrinkle structure. We used poly-3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS), the most widely used conductive polymer, as a thin film and adopted its stretchable wrinkle structure for stretchable electronic devices. The stretchability and durability of PEDOT:PSS were enhanced by sandwiching the PEDOT:PSS layer between two Parylene layers. The PEDOT:PSS layer was conductive at a stretch of up to 170%, and the change in resistance was less than 10% after 4000 cyclic loads. Additionally, we demonstrated a new concept of a flexible and stretchable light emitting device using the proposed Parylene/PEDOT:PSS/Parylene multi-layer and functionalized polydimethylsiloxane. [ABSTRACT FROM AUTHOR]

Under the coastal fisheries co-management regime in Japan, local fishers play important roles in deciding on and implementing local management measures. Therefore, using the case study of a hairtail trolling line fishery, we conducted a transdisciplinary research with fishers, processors, government officers, etc. Taking social and biological factors into account, we defined management criteria and targets (resource, economic, human community, and local food culture) in collaboration with local fishers. We chartered local fishing vessels to determine parameters that were easily understood by local fishers. We established a local consultative committee comprising fishers, processors, and distributors, and developed a fish distribution strategy to nurture the local hairtail food culture. The integrated effects of various management scenarios were evaluated by the operating model. We found that co-ordinated management by both the trolling line fishery and purse seiners in the neighbouring prefecture was required to achieve targets. Two realistic scenarios are recommended: a conservative scenario that could achieve targets even with few strong year classes, and an adaptive scenario that protects strong year classes, but relies on a higher frequency of these. We shared these results with the local fishers and government officers, which led to actual improvements in management measures. [ABSTRACT FROM AUTHOR]

A micro-structure supported on a droplet is subjected to capillary force and aligned dependent on its shape. If the droplet's boundary conditions at the bottom and the micro-structure are non-circular, capillary torque is exerted on the structures. The direction of torque is determined by the boundary conditions and the position of the structure. By changing the boundary conditions continuously, rotational motion of a plate was achieved. The boundary conditions of the droplet were controlled by electrowetting. We patterned electrodes in an annular shape on the plate supporting the droplet. By changing the voltage-applied electrodes, the boundary conditions were changed and the plate is rotated. The droplet and the plate worked as a capillary motor with this method. We report the relationship between the characteristics of the capillary motor and its rotational motion. We sandwiched a 3.0-μL water droplet between two plates and achieved a rotational motion of 720 rpm at maximum. [ABSTRACT FROM AUTHOR]

We developed a tunable wedge prism by electrowetting actuation. Our prism can shift the field of view to the left or to the right and is useful for small cameras and endoscopes because its field of view can be changed without the need for large instruments. It consists of two plates that face each other, and a liquid is sandwiched between them. The liquid and plates form a wedge when the angle between the plates is changed. We used electrowetting to change the angle between the plates. The wedge prism is small because the liquid driven by electrowetting works as a prism. In addition, the prism produces a clear field of view because its optical flatness is determined by the flatness of the plates. [ABSTRACT FROM AUTHOR]