Monolithic fabrication of millimeter-scale machines

Sreetharan, P S; Whitney, John P.; Strauss, Mike; Wood, Robert J.

doi:10.1088/0960-1317/22/5/055027

Cited by 159 publications

(138 citation statements)

References 19 publications

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“…cost, weight, printability, and porosity), HEPAs could be useful in applications benefitting from monolithic integration in paper-based printed microfluidic [6][7][8][9][10] and electronic devices, [16][17][18][19][20][21][22] paper MEMS, [16,23,24] printable and foldable micro machines, [24][25][26] and robots. [25,27,40] Their speed of actuation, and the force they produce, however, is low (by standards of more conventional electromagnetic and pneumatic / hydrolic systems), but they are also lighter, much less expensive, and much more easily integrated with paper devices (diagnostic, bioanalytical, and electromechanical systems, for example) than are the more universal systems.…”

Section: Resultsmentioning

confidence: 99%

“…[3][4][5] For example, we and others have used it for microfluidic [6][7][8][9][10] and electroanalytical devices as the basis for low-cost diagnostics, [11,12] as 3-D scaffolds for cell growth, [13][14][15] as a substrate for printed electronics, [16][17][18][19][20][21][22] and in micro-electromechanical systems (MEMS). [16,23,24] A missing component for paper-based devices is an electrically controlled actuator that is embedded within the paper, can be fabricated by printing, and continues to operate when the paper that supports it is creased and/or folded. Paper actuators that fulfill these requirements have the potential to allow control of liquid transport in paperbased microfluidic devices, to enable assembly of micro machines through self-folding, [24][25][26] and to serve as microactuators for paper devices.…”

Section: Introductionmentioning

confidence: 99%

“…[16,23,24] A missing component for paper-based devices is an electrically controlled actuator that is embedded within the paper, can be fabricated by printing, and continues to operate when the paper that supports it is creased and/or folded. Paper actuators that fulfill these requirements have the potential to allow control of liquid transport in paperbased microfluidic devices, to enable assembly of micro machines through self-folding, [24][25][26] and to serve as microactuators for paper devices. [25,27] If mechanical work could be performed with paper actuators, we could build new kinds of "paper-based machines".…”

Section: Introductionmentioning

confidence: 99%

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Electrically Activated Paper Actuators

Hamedi

Campbell

Rothemund

et al. 2016

Adv Funct Materials

144

153

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This paper describes the design and fabrication of electrically controlled paper actuators that operate based on the dimensional changes of that occur in paper when the moisture absorbed on the surface of the cellulose fibers changes. These actuators are called "Hygroexpansive Electrothermal Paper Actuators" (HEPAs). The actuators are made from paper, conducting polymer, and adhesive tape. They are lightweight, inexpensive, and can be fabricated using simple printing techniques. The central element of the HEPAs is a porous conducting path (used to provide electrothermal heating) that changes the moisture content of the paper and causes actuation. This conducting path is made by embedding a conducting polymer (PEDOT:PSS) within the paper, and thus making a paper / polymer composite that retains the porosity and hydrophilicity of paper. Different types of HEPAs (straight, pre-curved, and creased) achieved different types of motions (e.g., bending motion, accordion type motion). A theoretical model for their behavior is proposed. These actuators have been used for the manipulation of liquids, and for the fabrication of an optical shutter.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrically Activated Paper Actuators

Hamedi

Campbell

Rothemund

et al. 2016

Adv Funct Materials

144

153

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“…At small scales -for example, for aircraft of comparable size to insects and small birds -some of these techniques fail, typically owing to limited resolution. Alternative methods have been developed; for example, those based on folding (an inherently scalable technique) have been used to create insect-sized robots, avoiding the challenges that are inherent to macro-scale nuts-and-bolts approaches 20 .…”

Section: Actuation Power and Manufacturingmentioning

confidence: 99%

Science, technology and the future of small autonomous drones

Floreano

Wood

2015

Nature

1,009

552

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Drones, a popular nickname for unmanned aerial vehicles and micro aerial vehicles, often conjure up images of unmanned aeroplanes that fly thousands of miles for espionage and to deploy munitions. However, over the past few years, an increasing number of public and private research laboratories have been working on small, human-friendly drones that one day may autonomously fly in confined spaces and in close proximity to people. The development of these small drones, which is the main focus of this Review, has been supported by the miniaturization and cost reduction of electronic components (microprocessors, sensors, batteries and wireless communication units), largely driven by the portable electronic device industry. These improvements have enabled the prototyping and commercialization of small (typically less than 1 kg) drones at smartphone prices.Small drones will have important socio-economic impacts (Fig. 1). Images from drones that are capable of flying a few metres above the ground will fill a gap between expensive, weather-dependent and lowresolution images provided by satellites and car-based images limited to human-level perspectives and the availability of accessible roads. Specialized flying cameras and cloud-based data analytics will allow farmers to continuously monitor the quality of crop growth. Such platforms will enable construction companies to measure work progress in real time. Drones will let mining companies obtain precise volumetric data of excavations. Energy and infrastructure companies will be able to exhaustively survey pipelines, roads and cables. Humanitarian organizations could immediately assess and adapt aid efforts in continuously changing refugee camps. Transportation drones that are capable of safely taking off and landing in the proximity of buildings and humans will allow developing countries -without a suitable road network -to rapidly deliver goods and to finally unleash the full potential of their e-commerce telecommunication infrastructure. Transportation drones will also help developed countries to improve the quality of service in congested or remote areas, and will enable rescue organizations to quickly deliver medical supplies in the field and on demand. Inspection drones that are capable of flying in confined spaces will help fire-fighting and emergency units to assess dangers faster and more safely, logistic companies to detect cracks in the inner and outer shells of ships, road maintenance companies to measure signs of wear and tear in bridges and tunnels, security companies to improve building safety by monitoring areas outside the range of surveillance cameras, and disaster mitigation agencies to inspect partially collapsed buildings where ground clutter is an obstacle for terrestrial robots. Coordinated teams of autonomous drones will enable missions that last longer than the flight time of a single drone by allowing some drones to temporarily leave the team for battery replacement. Drone teams will permit rescue organizations to quickly deploy dedicated commu...

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“…While several devices have been demonstrated to deliver high power at very small-scale (1-100 mg), the fabrication processes are either long duration, [7] or rely on unconventional materials, [8] or are difficult to replicate. [9] In addition, the most established processes to make lightweight batteries rely on thin-film, solid electrolyte chemistries, which suffer from rate limitations at room temperature, [10,11] To create lighter mesoscale power sources, we have developed a method to fabricate ultra-lightweight, high power lithium-ion batteries by applying a laser micro manufacturing process, [12,13] to commercially available materials. The laser micro machining leads to micron scale precision in cutting and alignment, as well as scalable parallel fabrication.…”

Section: Ultra-lightweight High Power Density Lithium-ion Batteriesmentioning

confidence: 99%

Ultra‐Lightweight, High Power Density Lithium‐Ion Batteries

Duduta

Rivaz

Clarke

et al. 2018

Batteries & Supercaps

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Current fabrication methods for lithium-ion batteries impose a limit on how light a high power battery can be made. The lack of lightweight (< 300 mg), high power batteries is a significant constraint to the development of untethered micro-robots, wearable haptics, mobile computing, and biomedical applications. We have developed a laser micro-machining and assembly process which can produce batteries up to 30 times lighter than the lightest high power commercial cell, at comparable power densities (> 1 kW/kg). Our process is versatile and can be adapted to make custom geometries, miniature high voltage cells, and more, all while using a broad range of starting materials. We see this technology as a path to highly versatile miniature power sources, that will enable a wide range of small-scale applications.Existing fabrication technologies cannot be used to make lightweight, high power density lithium-ion batteries (< 300 mg). The need is increasing for these small, powerful batteries, as advances in fabrication techniques push the limits of miniaturization in robotics, [1] haptics, [2] wearable and biomedical technologies, [3] and mobile computing for the Internet of Things. [4] Unfortunately, current fabrication methods for lithium-ion cells force the end user to make a choice between high energy density and lightweight batteries (Figure 1(a)). Supercapacitors can provide even higher power density (> 10 kW/kg), but have very short discharge times (0.1-5 s), which limits the range of potential applications. [5] To push the limits of performance, we have developed a hybrid manufacturing approach which uses commercially available lithium-ion materials and a laser micro machining method to build lightweight (10-200 mg) high power density (> 1 kW/kg) batteries.Miniaturization of Li-ion batteries is limited by how the fabrication processes scale down, [5,6] Conventional Li-ion electrodes are made as planar films that are stacked into prismatic or cylindrical shapes. The stacked electrodes are infused with electrolyte, then sealed into a metallized film pouch, which prevents moisture from infiltrating into the battery. The materials and processes used to prevent moisture infiltration take up a significant amount of total battery weight, and scale unfavorably as the size of the battery is reduced. Furthermore, most nickel and aluminum commercial tabs weigh hundreds of milligrams, and need large areas for reliable welding to the electrodes. For high power devices, tabs and welds need to be oversized to avoid excessive resistive heating during fast charge or discharge. While several devices have been demonstrated to deliver high power at very small-scale (1-100 mg), the fabrication processes are either long duration, [7] or rely on unconventional materials, [8] or are difficult to replicate. [9] In addition, the most established processes to make lightweight batteries rely on thin-film, solid electrolyte chemistries, which suffer from rate limitations at room temperature, [10,11] To create lighter mesoscale power sources,...

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Monolithic fabrication of millimeter-scale machines

Cited by 159 publications

References 19 publications

Electrically Activated Paper Actuators

Electrically Activated Paper Actuators

Science, technology and the future of small autonomous drones

Ultra‐Lightweight, High Power Density Lithium‐Ion Batteries

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