New technologies to integrate electronics and sensors on or into objects can support the growth of embedded electronics. The method proposed in this paper has the huge advantage of being substrate-free and applicable to a wide range of target materials such as fiber-based composites, widely used in manufacturing, and for which monitoring applications such as fatigue, cracks, and deformation detection are crucial. Here, sensors are first fabricated on a donor substrate using standard microelectronic processes and then transferred to the host material by direct transfer printing.
View Article and Find Full Text PDFManufacturing an array of high-quality metallic pattern layers on a dielectric substrate remains a major challenge in the development of flexible and 3-D frequency selective surfaces (FSS). This paper proposes an improved fabrication solution for the 3-D FSS based on water transfer printing (WTP) technology. The main advantages of the proposed solution are its ability to transform complicated 2-D planar FSS patterns into 3-D structures while improving both manufacturing quality and production costs.
View Article and Find Full Text PDFSilicon nanowire (SiNW) arrays were coated with chromium nitride (CrN) for use as supercapacitor electrodes. The CrN layer of different thicknesses was deposited onto SiNWs using bipolar magnetron sputtering method. The areal capacitance of the SiNWs-CrN, as measured in 0.
View Article and Find Full Text PDFThe integration of electronics into the process flow of the additive manufacturing of 3D objects is demonstrated using water soluble films as a temporary flexible substrate. Three process variants are detailed to evaluate their capabilities to meet the additive manufacturing requirements. One of them, called water transfer printing, shows the best ability to fabricate electronics onto 3D additively manufactured objects.
View Article and Find Full Text PDFThe water transfer printing method is used to transfer patterned films on random three-dimensional objects. This industrially viable technology has been demonstrated to intimately wrap metallic and polymeric films around different materials. This method avoids the use of rigid substrate during the transfer step.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2015
Drop on Demand inkjet printing is an attractive method for device fabrication. However, the reliability of the key printing steps is still challenging. This explains why versatile functional inks are needed.
View Article and Find Full Text PDFSupplying liquid to droplet-based microfluidic microsystems remains a delicate task facing the problems of coupling continuous to digital or macro- to microfluidic systems. Here, we take advantage of superhydrophobic microgrids to address this problem. Insertion of a capillary tube inside a microgrid aperture leads to a simple and reconfigurable droplet generation setup.
View Article and Find Full Text PDFWhen a drop sits on a highly liquid-repellent surface (super-hydrophobic or super-omniphobic) made of periodic micrometer-sized posts, its contact-line can recede with very weak mechanical retention providing that the liquid stays on top of the microsized posts. Occurring in both sliding and evaporation processes, the achievement of low-contact-angle hysteresis (low retention) is required for discrete microfluidic applications involving liquid motion or self-cleaning; however, careful examination shows that during receding, a minute amount of liquid is left on top of the posts lying at the receding edge of the drop. For the first time, the heterogeneities of these deposits along the drop-receding contact-line are underlined.
View Article and Find Full Text PDFFollowing the achievement of superhydrophobicity which prevents water adhesion on a surface, superomniphobicity extends this high repellency property to a wide range of liquids, including oils, solvents, and other low surface energy liquids. Recent theoretical approaches have yield to specific microstructures design criterion to achieve such surfaces, leading to superomniphobic structured silicon substrate. To transfer this technology on a flexible substrate, we use a polydimethylsiloxane (PDMS) molding process followed by surface chemical modification.
View Article and Find Full Text PDF