The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Zhigang Wu - One of the best experts on this subject based on the ideXlab platform.
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High Resolution Patterning of Liquid Alloy by Shrinking the Substrate
2020Co-Authors: Seung Hee Jeong, Zhigang Wu, Albin Berglund, Ida Nilsson, Arne Sahlberg, Hugo Nguyen, Klas HjortAbstract:In order to overcome the current limitation in the resolution of the previous developed, Liquid Alloy patterning method, a shrinking substrate is, for the first time, employed. The current printing ...
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High-Fidelity Conformal Printing of 3D Liquid Alloy Circuits for Soft Electronics.
ACS Applied Materials & Interfaces, 2019Co-Authors: Shuo Zhang, Bei Wang, Jiajun Jiang, Kang Wu, Zhigang WuAbstract:Owing to the great deformability from fluid, Liquid Alloy-based soft electronics has inherent advantages over rigid-based ones for applications such as stretchable intelligence or soft robotics, where high fidelity of three-dimensional (3D) conformability or dynamic morphology is required. However, current fabrications heavily rely on planar techniques, which severely limit their great potential in such attracting applications. By tuning the wettability of Liquid Alloy on a soft substrate through a selective surface morphology modification, we present a flexography printing technique of Liquid Alloy circuits on both planar (from diverse materials) and 3D complex surfaces and investigate the tuning mechanism and the relation between Liquid Alloy wettability and surface morphology modification. In a demonstration, high-fidelity printing of Liquid Alloy circuits can be deployed not only on the outline but also on small pits of strawberry surface, and the circuits work well in a dynamic deformation. Furthermo...
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Sandwiched Polyethylene Shrink Film Masking with Tunable Resolution and Shape for Liquid Alloy Patterning
ACS Applied Polymer Materials, 2018Co-Authors: Bei Wang, Klas Hjort, Zhigang WuAbstract:Among numerous patterning techniques, masked Liquid Alloy printing is one of the most promising techniques for scalable fabrication of Liquid-Alloy-based stretchable electronics. Like any other mask-based process, its resolution is often constrained by the quality of the mask, and the fabrication cost increases drastically with increased resolution. In this work, by introducing a sandwiched thermal shrink polymer film masking technique and a corresponding intermediate release agent, fine Liquid Alloy patterns were demonstrated by using a mechanical cutting plotter together with a common oven. The final resolution and shape of the mask could be tuned based on the anisotropy of the shrink polymer film and other operational parameters of the technique. After shrinkage, the width of the patterned Liquid Alloy lines and space in-between could be tuned to less than one third of the original cut pattern, to about 35 and 60 μm, respectively, according to requirements. To better predict the final structure, severa...
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On-Demand Multi-Resolution Liquid Alloy Printing Based on Viscoelastic Flow Squeezing.
Polymers, 2018Co-Authors: Kang Wu, Pan Zhang, Fen Li, Zhigang WuAbstract:Recently, high-resolution patterning techniques of stretchable electronics advanced extensively. An important trend is to fabricate complex circuits with varied sizes in a small area, which is a technical challenge to current conductive ink printing technologies. Here, we introduce a new strategy for multi-resolution Liquid Alloy printing, which can tune the resolution of printed Liquid Alloy trace in real time with the squeezing effect of compound viscoelastic flow. A newly developed coaxial nozzle with the inner nozzle extension (CNINE) is used to wrap and squeeze Liquid Alloy steadily and effectively. By controlling the working parameters and compound flow properties, Liquid Alloy patterns with different widths are obtained continuously. This work offers a new way to rapidly manufacture complex stretchable electronics patterning in multi-resolution.
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Stretchable Thermoelectric Generators Metallized with Liquid Alloy.
ACS Applied Materials & Interfaces, 2017Co-Authors: Seung Hee Jeong, Shi-li Zhang, Klas Hjort, Zhigang Wu, Si Chen, Francisco Javier Cruz, Laurent Gravier, Zhi-bin ZhangAbstract:Conventional thermoelectric generators (TEGs) are normally hard, rigid, and flat. However, most objects have curvy surfaces, which require soft and even stretchable TEGs for maximizing efficiency of thermal energy harvesting. Here, soft and stretchable TEGs using conventional rigid Bi2Te3 pellets metallized with a Liquid Alloy is reported. The fabrication is implemented by means of a tailored layer-by-layer fabrication process. The STEGs exhibit an output power density of 40.6 μW/cm2 at room temperature. The STEGs are operational after being mechanically stretched-and-released more than 1000 times, thanks to the compliant contact between the Liquid Alloy interconnects and the rigid pellets. The demonstrated interconnect scheme will provide a new route to the development of soft and stretchable energy-harvesting avenues for a variety of emerging electronic applications.
Klas Hjort - One of the best experts on this subject based on the ideXlab platform.
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High Resolution Patterning of Liquid Alloy by Shrinking the Substrate
2020Co-Authors: Seung Hee Jeong, Zhigang Wu, Albin Berglund, Ida Nilsson, Arne Sahlberg, Hugo Nguyen, Klas HjortAbstract:In order to overcome the current limitation in the resolution of the previous developed, Liquid Alloy patterning method, a shrinking substrate is, for the first time, employed. The current printing ...
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Sandwiched Polyethylene Shrink Film Masking with Tunable Resolution and Shape for Liquid Alloy Patterning
ACS Applied Polymer Materials, 2018Co-Authors: Bei Wang, Klas Hjort, Zhigang WuAbstract:Among numerous patterning techniques, masked Liquid Alloy printing is one of the most promising techniques for scalable fabrication of Liquid-Alloy-based stretchable electronics. Like any other mask-based process, its resolution is often constrained by the quality of the mask, and the fabrication cost increases drastically with increased resolution. In this work, by introducing a sandwiched thermal shrink polymer film masking technique and a corresponding intermediate release agent, fine Liquid Alloy patterns were demonstrated by using a mechanical cutting plotter together with a common oven. The final resolution and shape of the mask could be tuned based on the anisotropy of the shrink polymer film and other operational parameters of the technique. After shrinkage, the width of the patterned Liquid Alloy lines and space in-between could be tuned to less than one third of the original cut pattern, to about 35 and 60 μm, respectively, according to requirements. To better predict the final structure, severa...
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Stretchable Thermoelectric Generators Metallized with Liquid Alloy.
ACS Applied Materials & Interfaces, 2017Co-Authors: Seung Hee Jeong, Shi-li Zhang, Klas Hjort, Zhigang Wu, Si Chen, Francisco Javier Cruz, Laurent Gravier, Zhi-bin ZhangAbstract:Conventional thermoelectric generators (TEGs) are normally hard, rigid, and flat. However, most objects have curvy surfaces, which require soft and even stretchable TEGs for maximizing efficiency of thermal energy harvesting. Here, soft and stretchable TEGs using conventional rigid Bi2Te3 pellets metallized with a Liquid Alloy is reported. The fabrication is implemented by means of a tailored layer-by-layer fabrication process. The STEGs exhibit an output power density of 40.6 μW/cm2 at room temperature. The STEGs are operational after being mechanically stretched-and-released more than 1000 times, thanks to the compliant contact between the Liquid Alloy interconnects and the rigid pellets. The demonstrated interconnect scheme will provide a new route to the development of soft and stretchable energy-harvesting avenues for a variety of emerging electronic applications.
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Thermal elastomer composites for soft transducers
2015 Transducers - 2015 18th International Conference on Solid-State Sensors Actuators and Microsystems (TRANSDUCERS), 2015Co-Authors: S.h. Jeong, S. Chen, L. Gravier, K. Gamstedt, S.-l. Zhang, Z.-b. Zhang, Z.g. Wu, Klas HjortAbstract:Thermal elastomer composites (TECs) that are electrically insulating have potential usage in soft transducers targeting thermal sensors and actuators, or thermoelectric generators. In this work, such a TEC is prepared by dispersing droplets of a gallium based Liquid Alloy (Galinstan) into a polydimethysiloxane (PDMS) base matrix. The results indicate that the TEC is highly elastic and shows an up to three-fold increase in thermal conductivity from that of PDMS. A thermoelectric device with the TEC packaging is demonstrated with a higher efficiency than that with pristine PDMS packaging.
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Mechanically Stretchable and Electrically Insulating Thermal Elastomer Composite by Liquid Alloy Droplet Embedment
Scientific Reports, 2015Co-Authors: Seung Hee Jeong, Jinxing Huo, Erik Kristofer Gamstedt, Johan Liu, Shi-li Zhang, Zhi-bin Zhang, Klas Hjort, Si Chen, Zhigang WuAbstract:Stretchable electronics and soft robotics have shown unsurpassed features, inheriting remarkable functions from stretchable and soft materials. Electrically conductive and mechanically stretchable materials based on composites have been widely studied for stretchable electronics as electrical conductors using various combinations of materials. However, thermally tunable and stretchable materials, which have high potential in soft and stretchable thermal devices as interface or packaging materials, have not been sufficiently studied. Here, a mechanically stretchable and electrically insulating thermal elastomer composite is demonstrated, which can be easily processed for device fabrication. A Liquid Alloy is embedded as Liquid droplet fillers in an elastomer matrix to achieve softness and stretchability. This new elastomer composite is expected useful to enhance thermal response or efficiency of soft and stretchable thermal devices or systems. The thermal elastomer composites demonstrate advantages such as thermal interface and packaging layers with thermal shrink films in transient and steady-state cases and a stretchable temperature sensor.
Seung Hee Jeong - One of the best experts on this subject based on the ideXlab platform.
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High Resolution Patterning of Liquid Alloy by Shrinking the Substrate
2020Co-Authors: Seung Hee Jeong, Zhigang Wu, Albin Berglund, Ida Nilsson, Arne Sahlberg, Hugo Nguyen, Klas HjortAbstract:In order to overcome the current limitation in the resolution of the previous developed, Liquid Alloy patterning method, a shrinking substrate is, for the first time, employed. The current printing ...
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Stretchable Thermoelectric Generators Metallized with Liquid Alloy.
ACS Applied Materials & Interfaces, 2017Co-Authors: Seung Hee Jeong, Shi-li Zhang, Klas Hjort, Zhigang Wu, Si Chen, Francisco Javier Cruz, Laurent Gravier, Zhi-bin ZhangAbstract:Conventional thermoelectric generators (TEGs) are normally hard, rigid, and flat. However, most objects have curvy surfaces, which require soft and even stretchable TEGs for maximizing efficiency of thermal energy harvesting. Here, soft and stretchable TEGs using conventional rigid Bi2Te3 pellets metallized with a Liquid Alloy is reported. The fabrication is implemented by means of a tailored layer-by-layer fabrication process. The STEGs exhibit an output power density of 40.6 μW/cm2 at room temperature. The STEGs are operational after being mechanically stretched-and-released more than 1000 times, thanks to the compliant contact between the Liquid Alloy interconnects and the rigid pellets. The demonstrated interconnect scheme will provide a new route to the development of soft and stretchable energy-harvesting avenues for a variety of emerging electronic applications.
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Mechanically Stretchable and Electrically Insulating Thermal Elastomer Composite by Liquid Alloy Droplet Embedment
Scientific Reports, 2015Co-Authors: Seung Hee Jeong, Jinxing Huo, Erik Kristofer Gamstedt, Johan Liu, Shi-li Zhang, Zhi-bin Zhang, Klas Hjort, Si Chen, Zhigang WuAbstract:Stretchable electronics and soft robotics have shown unsurpassed features, inheriting remarkable functions from stretchable and soft materials. Electrically conductive and mechanically stretchable materials based on composites have been widely studied for stretchable electronics as electrical conductors using various combinations of materials. However, thermally tunable and stretchable materials, which have high potential in soft and stretchable thermal devices as interface or packaging materials, have not been sufficiently studied. Here, a mechanically stretchable and electrically insulating thermal elastomer composite is demonstrated, which can be easily processed for device fabrication. A Liquid Alloy is embedded as Liquid droplet fillers in an elastomer matrix to achieve softness and stretchability. This new elastomer composite is expected useful to enhance thermal response or efficiency of soft and stretchable thermal devices or systems. The thermal elastomer composites demonstrate advantages such as thermal interface and packaging layers with thermal shrink films in transient and steady-state cases and a stretchable temperature sensor.
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Stretchable wireless power transfer with a Liquid Alloy coil
2015 28th IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 2015Co-Authors: Seung Hee Jeong, Zhigang WuAbstract:An integrated stretchable wireless power transfer device was demonstrated by packaging rigid electronic chips onto a Liquid Alloy coil patterned on a half-cured polydimethylsiloxane (PDMS) surface. To obtain low enough resistance, the long Liquid Alloy coil with a large cross section was made with a tape transfer masking followed by spray deposition of the Liquid Alloy. The measured results indicated the wireless power transfer efficiency reached 10% at 140 kHz and good performance under 25% overall strain. Different sizes of Liquid Alloy coils and a soft magnetic composite core were tested to improve the efficiency of the system.
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Liquid Alloy printing of microfluidic stretchable electronics
Lab on a Chip, 2012Co-Authors: Seung Hee Jeong, Klas Hjort, Anton Hagman, Magnus Jobs, Johan Sundqvist, Zhigang WuAbstract:Recently, microfluidic stretchable electronics has attracted great interest from academia since conductive Liquids allow for larger cross-sections when stretched and hence low resistance at longer lengths. However, as a serial process it has suffered from low throughput, and a parallel processing technology is needed for more complex systems and production at low costs. In this work, we demonstrate such a technology to implement microfluidic electronics by stencil printing of a Liquid Alloy onto a semi-cured polydimethylsiloxane (PDMS) substrate, assembly of rigid active components, encapsulation by pouring uncured PDMS on-top and subsequent curing. The printing showed resolution of 200 μm and linear resistance increase of the Liquid conductors when elongated up to 60%. No significant change of resistance was shown for a circuit with one LED after 1000 times of cycling between a 0% and an elongation of 60% every 2 s. A radio frequency identity (RFID) tag was demonstrated using the developed technology, showing that good performance could be maintained well into the radio frequency (RF) range.
Devendra Adhikari - One of the best experts on this subject based on the ideXlab platform.
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Theoretical investigation of mixing properties of Sb-Sn binary Liquid Alloy at 905K
Bibechana, 2017Co-Authors: H. K. Limbu, K. K. Mishra, Devendra AdhikariAbstract:The thermodynamic, microscopic, surface and transport properties of Sb-Sn Liquid Alloy at 905K have been studied using regular solution model. In thermodynamic properties, free energy of mixing(GM) , activity(a), entropy of mixing(SM), heat of mixing (HM) have been studied. To understand structural behavior of the Liquid Alloys concentration fluctuations in the long wavelength limit i.e. (Scc(0)) and short range order parameter (α1) have been computed. Surface property is studied with the help of Butler’s model while transport property is computed from Moelwyn-Hughes equation. The theoretical and experimental values of thermodynamic and microscopic properties of Sb-Sn Liquid Alloy at 905K have been compared. In present work the value of interchange energy (w) is found to be negative suggesting that there is a tendency of unlike atoms pairing (i.e. Sb-Sn) as the nearest neighbor indicating the ordering behavior in Sb-Sn Liquid Alloy. The symmetric behavior of concentration fluctuations of the Liquid Alloy has been well explained by the model. The temperature dependence of interchange energy (w) has been found during the computation of entropy of mixing (SM) and heat of mixing (HM) of the Liquid Alloy.BIBECHANA 15 (2018) 1-10
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Mixing properties of Ni-Pd Liquid Alloy
Bibechana, 2013Co-Authors: L. Gurung, R. P. Koirala, Devendra AdhikariAbstract:In this work, thermodynamic and microscopic properties of NiPd Liquid Alloy at 1873 K have been studied using a simple theory of mixture. In thermodynamic properties, free energy of mixing, heat of mixing and entropy of mixing have been studied. To understand the structural behaviour of the Alloy concentration fluctuation in long wavelength limit and chemical short range order parameter have been computed. The NiPd melt at 1873 K is found to be slightly deviated from regular behaviour. The best estimated value of energy parameter is found to be positive. The Alloy is found to be weakly segregating system. The symmetric behaviour of all functions has been well explained by the simple theory of mixing The mixing behaviour of binary Liquid Alloys may be explained in terms of thermodynamic and microscopic properties. Thermodynamic behaviour of the Alloys is understood by the knowledge of free energy of mixing ( �GM), heat of mixing ( �HM), entropy of mixing ( �SM) and activity (a). Structural behavior is comprehended by the interpretation of concentration fluctuation in long wavelength limit (S CC (0)) and chemical short range order parameter (α 1). The thermodynamic properties of binary Liquid Alloys give the information about the maximum stable composition, bonding strength and most mixed state of the Alloy. The microscopic properties provide the information about the local arrangement of atoms. It is, therefore, obvious that without having a clear knowledge of the properties of Alloys in Liquid state it is not possible to understand the energetics of the formation of solid Alloys. This requirements demand extensive investigations for understanding the properties of Alloys in the Liquid state. Several theoreticians (1�10) have long been carried out to understand various properties of Alloys in their Liquid states. The NiPd Alloy is used in hydrogen sensors. This al loy has also glass forming properties at eutectic region around 45% of Pd. The knowledge of thermodynamic and structural properties at Liquid state is essential for investigating the solidification process. Hence, it is important to study different properties of NiPd Liquid Alloy for its industrial applications. In this work we intend to study the thermodynamic and structural properties of NiPd Alloy in Liquid state at 1873 K by using simple theory of mixing. In next section the theoretical formalism is presented. Section 3 deals with results and discussion and conclusions are outlined in section 4.
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Phase separation in Na–K Liquid Alloy
Phase Transitions, 2012Co-Authors: Devendra Adhikari, B.p. SinghAbstract:The quasi-chemical expression for weakly interacting binary Alloy has been applied to obtain energy parameters and their temperature derivatives for Na–K Liquid Alloy at 384 K. These energy parameters have then been used to calculate thermodynamic functions, such as free energy of mixing, heat of mixing, entropy of mixing and microscopic functions, such as concentration fluctuation in long wavelength limit, Warren–Cowley short-range order parameter, ratio of mutual and self-diffusion coefficients. The analysis reveals that the energy parameters are temperature dependent and the Na–K Liquid Alloy at 384 K is a weakly interacting homocoordination system. The observed thermodynamic properties of Na–K Alloy in molten state have successfully been explained by assuming Na2K complex on the basis of the quasi-chemical formalism for a weakly interacting system.
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Mixing properties of Al–Mg Liquid Alloy
Indian Journal of Physics, 2012Co-Authors: Devendra Adhikari, B.p. SinghAbstract:Flory’s model has been used to study the mixing properties of Al–Mg Liquid Alloy at 1,073 K. The values of different thermodynamic parameters obtained from this model are compared with corresponding experimental values. Most of the computed values are found to be in good agreement with the observed values.
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Energetics of Cd-based binary Liquid Alloys
Journal of Non-crystalline Solids, 2012Co-Authors: Devendra Adhikari, B.p. SinghAbstract:Abstract The thermodynamic properties such as, free energy of mixing (GM), heat of mixing (HM), entropy of mixing (SM) and microscopic properties such as, concentration fluctuation in long wavelength limit (SCC(0)), Warren–Cowely short range ordering parameter (α1), ratio of mutual and intrinsic diffusion coefficients (DM/Did) of two Cd-based Liquid Alloys have been studied by using two different models. The properties of Cd–Hg Liquid Alloy at 600 K have been studied on the basis of regular solution model, and the properties of Cd–Na Liquid Alloy at 673 K have been studied on the basis of quasi-chemical expression for weakly interacting system.
Zi-kui Liu - One of the best experts on this subject based on the ideXlab platform.
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Accurate determination of thermodynamic properties for Liquid Alloys based on ab initio molecular dynamics simulation
Fluid Phase Equilibria, 2013Co-Authors: Jiajia Han, Xingjun Liu, William Yi Wang, Yanli Wang, Cuiping Wang, Zi-kui LiuAbstract:To improve the quality of the predicted thermodynamic properties of Liquid Alloy containing ferromagnetic transition metal with a highly non-ideal structure, a procedure has been introduced based on ab initio molecular dynamics simulation. In the context of this approach, the thermodynamic properties are physically described and the thermodynamic quantities can be rigorously predicted. As an example, the thermodynamic properties of Liquid Al–Fe Alloys are calculated as a function of temperature and composition. It is found a good agreement between the calculated and experimental data for the enthalpy and entropy of mixing for Liquid pure metal (Al, Fe) and Alloys (Al–Fe). In addition, the procedure proposed in the present study can be extended to any multicomponent metal systems.