Name: fabrication of soft pneumatic network actuators with oblique chambers
Uploaded: 2018-08-17T14:30:00
Description: Watch this Scientific Journal Video about Fabrication of Soft Pneumatic Network Actuators with Oblique Chambers at JoVE.com

This work was supported by the National Natural Science Foundation of China under Grant 51622506 and the Science and Technology Commission of Shanghai Municipality under Grant 16JC1401000.

NOTE: The protocol provides the fabrication procedures of a soft pneumatic network actuator. Before the fabrication procedure, a set of molds and several actuator-tubing connectors, which are designed with computer-aided design (CAD) software must be 3-D-printed in advance. The molds are shown in Figure 1B.
1. Silicone Elastomer Preparation
<ol>
	<li>Weigh 5 g of silicone elastomer part B and 45 g of part A [9:1 (A:B) parts by weight] in the sam...

<ol>
	<li>Rus, D., Tolley, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design,+fabrication+and+control+of+soft+robots.">Design, fabrication and control of soft robots.</a> Nature. 521 (7553), 467-475 (2015).</li><li>Ilievski, F., Mazzeo, A. D., Shepherd, R. F., Chen, X., Whitesides, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Soft+robotics+for+chemists.">Soft robotics for chemists.</a> Angewandte Chemie International Edition. 50 (8), 1890-1895 (2011).</li><li>Shepherd, R. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multigait+soft+robot.">Multigait soft robot.</a> Proceedings of the National Academy of Sciences of the United States of America. 108 (51), 20400-20403 (2011).</li><li>Yap, H. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+fully+fabric-based+bidirectional+soft+robotic+glove+for+assistance+and+rehabilitation+of+hand+impaired+patients.">A fully fabric-based bidirectional soft robotic glove for assistance and rehabilitation of hand impaired patients.</a> IEEE Robotics and Automation Letters. 2 (3), 1383-1390 (2017).</li><li>Yang, Y., Chen, Y., Li, Y., Chen, M. Z. Q., Wei, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioinspired+Robotic+Fingers+Based+on+Pneumatic+Actuator+and+3D+Printing+of+Smart+Material.">Bioinspired Robotic Fingers Based on Pneumatic Actuator and 3D Printing of Smart Material.</a> Soft Robotics. 4 (2), 147-162 (2017).</li><li>Gu, G. Y., Zhu, J., Zhu, L. M., Zhu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+survey+on+dielectric+elastomer+actuators+for+soft+robots.">A survey on dielectric elastomer actuators for soft robots.</a> Bioinspiration &amp; Biomimetics. 12 (1), 011003 (2017).</li><li>Holland, D. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+soft+robotics+toolkit:+Strategies+for+overcoming+obstacles+to+the+wide+dissemination+of+soft-robotic+hardware.">The soft robotics toolkit: Strategies for overcoming obstacles to the wide dissemination of soft-robotic hardware.</a> IEEE Robotics &amp; Automation Magazine. 24 (1), 57-64 (2017).</li><li>Galloway, K. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Soft+Robotic+Grippers+for+Biological+Sampling+on+Deep+Reefs.">Soft Robotic Grippers for Biological Sampling on Deep Reefs.</a> Soft Robotics. 3 (1), 23-33 (2016).</li><li>Polygerinos, P., Wang, Z., Galloway, K. C., Wood, R. J., Walsh, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Soft+robotic+glove+for+combined+assistance+and+at-home+rehabilitation.">Soft robotic glove for combined assistance and at-home rehabilitation.</a> Robotics and Autonomous Systems. 73, 135-143 (2015).</li><li>Tolley, M. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Resilient,+Untethered+Soft+Robot.">A Resilient, Untethered Soft Robot.</a> Soft Robotics. 1 (3), 213-223 (2014).</li><li>Ainla, A., Verma, M. S., Yang, D., Whitesides, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Soft,+Rotating+Pneumatic+Actuator.">Soft, Rotating Pneumatic Actuator.</a> Soft Robotics. 4 (3), 297-304 (2017).</li><li>Koizumi, Y., Shibata, M., Hirai, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rolling+tensegrity+driven+by+pneumatic+soft+actuators.">Rolling tensegrity driven by pneumatic soft actuators.</a> 2012 IEEE International Conference on Robotics and Automation (ICRA). , (2012).</li><li>Connolly, F., Polygerinos, P., Walsh, C. J., Bertoldi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+Programming+of+Soft+Actuators+by+Varying+Fiber+Angle.">Mechanical Programming of Soft Actuators by Varying Fiber Angle.</a> Soft Robotics. 2 (1), 26-32 (2015).</li><li>Connolly, F., Walsh, C. J., Bertoldi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automatic+design+of+fiber-reinforced+soft+actuators+for+trajectory+matching.">Automatic design of fiber-reinforced soft actuators for trajectory matching.</a> Proceedings of the National Academy of Sciences of the United States of America. 114 (1), 51-56 (2017).</li><li>Martinez, R. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Robotic+tentacles+with+three-dimensional+mobility+based+on+flexible+elastomers.">Robotic tentacles with three-dimensional mobility based on flexible elastomers.</a> Advanced Materials. 25 (2), 205-212 (2013).</li><li>Polygerinos, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+of+Soft+Fiber-Reinforced+Bending+Actuators.">Modeling of Soft Fiber-Reinforced Bending Actuators.</a> IEEE Transactions on Robotics. 31 (3), 778-789 (2015).</li><li>Mosadegh, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pneumatic+Networks+for+Soft+Robotics+that+Actuate+Rapidly.">Pneumatic Networks for Soft Robotics that Actuate Rapidly.</a> Advanced Functional Materials. 24 (15), 2163-2170 (2014).</li><li>Wang, T., Ge, L., Gu, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Programmable+design+of+soft+pneu-net+actuators+with+oblique+chambers+can+generate+coupled+bending+and+twisting+motions.">Programmable design of soft pneu-net actuators with oblique chambers can generate coupled bending and twisting motions.</a> Sensors and Actuators A: Physical. 271, 131-138 (2018).</li><li>Marchese, A. D., Katzschmann, R. K., Rus, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Recipe+for+Soft+Fluidic+Elastomer+Robots.">A Recipe for Soft Fluidic Elastomer Robots.</a> Soft Robotics. 2 (1), 7-25 (2015).</li></ol>

The paper presents a method protocol to guide the fabrication of soft pneumatic network actuators with oblique chambers. Following the protocol, one actuator can be fabricated independently within 3 h. The key steps in the protocol can be summarized as follows. (i) The silicone elastomer is prepared in proportion and mixed well. (ii) The silicone elastomer is poured into the mold for the fabrication of the chamber part and the base part. (iii) The bubbles on the exposed surface are pierced and any excess silicone elastom...

Soft pneumatic actuators (SPAs) are soft devices that can be actuated by the simple input of air pressure1,2. They can be fabricated with diverse materials, such as silicone elastomers3, fabrics4, shape-memory polymers5, and dielectric elastomers6. Researchers have benefited from their nature of compliance, dexterous motions, and simple fabrication methods7, such that SPAs have become one of the most promising devices for soft robotics applications8,9. SPAs can realize various sophisticated motions, such as creeping10, rotation11, and rolling12 based on various types of deformation, including extending, expanding, bending, and twisting13,14. To be able to make different types of motions, SPAs are designed in different structures, such as a linear body with parallel channels15, a monolithic chamber with fiber-reinforcements16, and networks of repeated sub-chambers17. Among them, the SPAs with networks of repeated sub-chambers, the soft pneumatic network actuators, are widely employed because they can generate large deformations under a relatively low input pressure. However, in most of the previous designs, this type of actuators can only generate bending motions in 2-D space, which greatly limits their applications.
A soft pneumatic network actuator consists of a linearly arranged group of chambers connected by an internal channel. Each cubic chamber contains a pair of opposite walls which are thinner than the other pair and produces a two-sided inflation in the direction perpendicular to the thinner walls. Originally, the thinner walls of the chambers are perpendicular to the long axis of the actuator body and inflate along with the long axis. These collinear inflations in chambers and the non-extensible base lead to an integral pure bending of the actuator. To explore the actuator&#39;s motion in 3-D space, the orientation of the chambers is tuned so that the thinner-side walls are no longer perpendicular to the long axis of the actuator (Figure 1A), which enables the inflation direction of each chamber to offset from the axis and become not collinear. All the parallel but not-collinear inflations change the motion of the actuator into a coupled bending and twisting motion in 3-D space18. This coupled motion enables the actuators more flexibility and dexterity and makes the actuators a suitable candidate for more practical applications, such as flexible manipulators, biologically inspired robots, and medical devices.
This protocol shows the fabrication method of this kind of soft pneumatic network actuators with oblique chambers. It includes preparing the silicone elastomer, fabricating the chamber and base parts, assembling the actuator, connecting the tubing, checking for leaks, and, if necessary, repairing the actuator. It can also be used to fabricate normal soft pneumatic network actuators and other soft actuators which can be produced with some simple modifications to the molding method. We provide detailed steps to fabricate a soft pneumatic actuator with 30&#176; oblique chambers. For different applications, actuators with different chamber angles can be fabricated according to the same protocol. Apart from that, the actuators can be combined to form a multi-actuator system for various demands.

<table border="0" cellpadding="0" cellspacing="0" style="width:796px;" width="794">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:207px;">Silicone elastomer</td>
			<td style="width:168px;">Wacker</td>
			<td style="width:135px;">ELASTOSIL M4601 A/B</td>
			<td style="width:287px;">Material of the actuators</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:207px;">Syringe&#160;</td>
			<td style="width:168px;">Shanghai Kindly Medical Instruments&#160;</td>
			<td style="width:135px;">10 ml</td>
			<td style="width:287px;">Used to inject silicone rubber into the hole of the mold for fabricating the connection end</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:207px;">Precision scale</td>
			<td style="width:168px;">Shanghai Hochoice</td>
			<td style="width:135px;">UTP-313</td>
			<td style="width:287px;">Used to weigh the silicone rubber</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:207px;">Planetary centrifugal vacuum mixer</td>
			<td style="width:168px;">THINKY</td>
			<td style="width:135px;">ARE-310</td>
			<td style="width:287px;">Used to mix the silicone rubber and defoam after mixing process</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:207px;">Release agent</td>
			<td style="width:168px;">Smooth-on</td>
			<td style="width:135px;">Release 200</td>
			<td style="width:287px;">Used for ease of demolding&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:207px;">Needle</td>
			<td style="width:168px;">Shanghai Kindly Medical Instruments&#160;</td>
			<td style="width:135px;"></td>
			<td style="width:287px;">Used for Piercing the bubbles form on the surface</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:207px;">Utility blade</td>
			<td style="width:168px;">M&#38;G Chenguang Stationery</td>
			<td style="width:135px;">ASS91325</td>
			<td style="width:287px;">Used for Scraping off excess silicone rubber along the upper surface of the mold&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:207px;">Vacuum oven</td>
			<td style="width:168px;">Ningbo SI Instrument</td>
			<td style="width:135px;">DZF-6050</td>
			<td style="width:287px;">Used to reduce the cure time of the silicone rubber</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:207px;">Male stud push in fit pneumatic fitting</td>
			<td style="width:168px;">Zhe Jiang BLCH Pneumatic Science &#38; Technology</td>
			<td style="width:135px;">PC4-01</td>
			<td style="width:287px;">Used to connect the tubing and the 3D-printed actuator tubing connector</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:207px;">Tubing</td>
			<td style="width:168px;">SMC</td>
			<td style="width:135px;">TU0425</td>
			<td style="width:287px;">Used for actuating the actuators</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:207px;">Vacuum pump</td>
			<td style="width:168px;">Zhe Jiang BLCH Pneumatic Science &#38; Technology</td>
			<td style="width:135px;"></td>
			<td style="width:287px;">Used as the air source</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:207px;">Pressure valve</td>
			<td style="width:168px;">Zhe Jiang BLCH Pneumatic Science &#38; Technology</td>
			<td style="width:135px;">IR1000-01BG</td>
			<td style="width:287px;">Used for adjusting the input air pressure</td>
		</tr>
	</tbody>
</table>

fabrication of soft pneumatic network actuators with oblique chambers

Soft pneumatic network actuators have become one of the most promising actuation devices in soft robotics which benefits from their large bending deformation and low input. However, their monotonous bending motion form in two-dimensional (2-D) space keeps them away from wide applications. This paper presents a detailed fabrication method of soft pneumatic network actuators with oblique chambers, to explore their motions in three-dimensional (3-D) space. The design of oblique chambers enables actuators with tunable coupled bending and twisting capabilities, which gives them the possibility to move dexterously in flexible manipulators, to become biologically inspired robots and medical devices. The fabrication process is based on the molding method, including the silicone elastomer preparation, chamber and base parts fabrication, actuator assembly, tubing connections, checks for leaks, and actuator repair. The fabrication method guarantees the rapid manufacturing of a series of actuators with only a few modifications in the molds. The test results show the high quality of the actuators and their prominent bending and twisting capabilities. Experiments of the gripper demonstrate the advantages of the development in adapting to objects with different diameters and providing sufficient friction.

Single Actuator: 
To verify the fabrication method and demonstrate the function of the actuator, 30&#176;, 45&#176;, and 60&#176; actuators were fabricated and tested. For the experiment set-up, an air pump was employed to activate the valve. The valve was connected to the actuator to control the internal pressure. The single actuator was fixed at its connection end and placed vertically. While the actuator was being pressurized, two digital cameras were used to capt...

Watch this Scientific Journal Video about Fabrication of Soft Pneumatic Network Actuators with Oblique Chambers at JoVE.com

Fabrication of Soft Pneumatic Network Actuators with Oblique Chambers

Here we present a fabrication method of soft pneumatic network actuators with oblique chambers. The actuators are capable of generating coupled bending and twisting motions, which broadens their application in soft robotics.

Soft pneumatic network actuators have become one of the most promising actuation devices in soft robotics which benefits from their large bending ...

This method answers the key questions in the field of soft cell robotics by showing the fabrication method of soft pneumatic network actuators with oblique chambers that characterizes coupled bending and twisting motions. The main advantage of this technique is that it is fast, reliable, low-cost and suitable for the fabrication of soft pneumatic actuators with varied structures. Generally, individuals new to this method will struggle because the fabrication contains many steps, and one minor inappropriate operation can cause lethal failure of the actuators.The fabrication process requires molds. Design and 3D print a set of molds for the actuator with a 30 degree oblique chamber. Two parts will form the chamber mold, with one part having a hole to create a tubing connection.The third part will form a base. Next, place a mixing container on a scale. In separate syringes, have silicone elastomer component parts A and B.Use the syringes and scale to add the desired mass of each component to the mixing container.Now, move the mixing container to a Planetary Centrifugal mixer and mix well. After mixing, the silicone elastomer is ready for the protocol. Work with the mold pieces for the chamber.On each of the pieces, evenly spray mold release agent for silicone elastomer products. Orient the two pieces properly and bring them together to assemble the mold. Hold both ends of the mold with clips to prevent leakage.Get five milliliters of silicone elastomer with a syringe. Inject the elastomer slowly into the hole of the mold to fabricate the connection end. Then, fill the whole mold with the silicone elastomer.Use a low-flow rate and move the elastomer back and forth slowly. Once the mold is filled, use a needle to pierce any bubbles that form on the surface. Use a blade to scrape off excess elastomer on the upper surface of the mold.Now, place the mold in a 70 degrees Celsius oven until it is cured. After curing, inspect the mold. Use a syringe to inject silicone elastomer into bubbles and holes on the surface of the actuator.Scrape off any excess elastomer on the surface. Return the mold to the 70 degrees Celsius oven until it is cured. This is an example of a chamber produced by these steps after curing and demolding.Get the mold piece for the base. Spray mold release agent for the silicone elastomer evenly on its surface. Pour the silicone elastomer into the mold to fill it completely.Then, with a needle, pierce any bubbles that form on the surface. Scrape off any excess silicone elastomer along the upper surface with a blade. Place the mold in a 70 degree Celsius oven until the silicone elastomer is cured.This is an example of the base produced by these steps after curing and demolding. At this point, the actuator components are ready. Work with both a chamber and a base.Begin by pouring a one millimeter thick layer of silicone elastomer on one face of the base. Then, place the chamber part on the base. There will be a space between the two pieces.Use a syringe to inject silicone elastomer into the space. Place the actuator in the oven at 70 degrees Celsius until the elastomer is cured. After curing the actuator, tap the actuator tubing connector.It should accept the screw of a male stud push-in fit pneumatic fitting. With a needle, pierce the connection end of the actuator along the central line of the cylinder. Use a steel rod to increase the diameter of the hole to about two millimeters.Get the actuator tubing connector and screw it into the actuator. Once it is in place, push a section of tubing into the pneumatic fitting. The final step is to check for leaks.For this, use a container of water that can cover the actuator. Get the actuator and connect it to an air source. Place the entire actuator into the water and pressurize it.Observe whether bubbles are formed due to a leak. After the test, remove the actuator from the water. In this video, a 30 degree actuator starts under zero applied air pressure.As the pressure increases from zero kilopascals to 90 kilopascals, without interruption, the actuator both bends and twists. As the pressure is reduced, it returns to its original state. The bending angle for the actuator is defined as the angle between the body line in unactuated position and the body line in the actuated position.The twisting angle is the angle between the tip line in the unactuated position and the actuated position. This plot shows the bending angle as a function of pressure for actuators with oblique angles of 30, 45 and 60 degrees. Here is a similar plot for the twisting angle as a function of pressure.Note the difference in the vertical scales. While attempting this procedure, it is important to remember to pierce any bubbles that form on the top surface and scrape off excess elastomer on the upper surface of the mold before placing it into the oven. In this procedure, the silicone elastomer can be mixed manually and the elastomer can be cured at room temperature if the mixer and oven are not available.After its development, this method has paved the way for researchers in the fabrication of soft pneumatic actuators to explore oblique chambers capable of bending and twisting motion in 3D space. Don't forget that working with needles and blades can be extremely hazardous and attention should be paid;avoiding any hurt. In addition, nitrile gloves should always be worn when working with silicone elastomers.

fabrication-of-soft-pneumatic-network-actuators-with-oblique-chambers

Research

JoVE Journal

Engineering

Fabrication of Low Temperature Carbon Nanotube Vertical Interconnects Compatible with Semiconductor Technology

We demonstrate a method for the low temperature growth (350 &#176;C) of vertically-aligned carbon nanotubes (CNT) bundles on electrically conductive thin-films. Due to the low growth temperature, the process allows integration with modern low-&#954; dielectrics and some flexible substrates. The process is compatible with standard semiconductor fabrication, and a method for the fabrication of electrical 4-point probe test structures for vertical interconnect test structures is presented. Using scanning electron microscopy the morphology of the CNT bundles is investigated, which demonstrates vertical alignment of the CNT and can be used to tune the CNT growth time. With Raman spectroscopy the crystallinity of the CNT is investigated. It was found that the CNT have many defects, due to the low growth temperature. The electrical current-voltage measurements of the test vertical interconnects displays a linear response, indicating good ohmic contact was achieved between the CNT bundle and the top and bottom metal electrodes. The obtained resistivities of the CNT bundle are among the average values in the literature, while a record-low CNT growth temperature was used.

A method for the growth of low temperature vertically-aligned carbon nanotubes, and the subsequent fabrication of vertical interconnect electrical test structures using semiconductor fabrication is presented.

We demonstrate a method for the low temperature growth (350 &#176;C) of vertically-aligned carbon nanotubes (CNT) bundles on electrically conductive ...

Fabrication Process of Silicone-based Dielectric Elastomer Actuators

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an elastomeric dielectric membrane sandwiched between two compliant electrodes. The large actuation strains of these transducers when used as actuators (over 300% area strain) and their soft and compliant nature has been exploited for a wide range of applications, including electrically tunable optics, haptic feedback devices, wave-energy harvesting, deformable cell-culture devices, compliant grippers, and propulsion of a bio-inspired fish-like airship. In most cases, DETs are made with a commercial proprietary acrylic elastomer and with hand-applied electrodes of carbon powder or carbon grease. This combination leads to non-reproducible and slow actuators exhibiting viscoelastic creep and a short lifetime. We present here a complete process flow for the reproducible fabrication of DETs based on thin elastomeric silicone films, including casting of thin silicone membranes, membrane release and prestretching, patterning of robust compliant electrodes, assembly and testing. The membranes are cast on flexible polyethylene terephthalate (PET) substrates coated with a water-soluble sacrificial layer for ease of release. The electrodes consist of carbon black particles dispersed into a silicone matrix and patterned using a stamping technique, which leads to precisely-defined compliant electrodes that present a high adhesion to the dielectric membrane on which they are applied.

This manuscript shows the fabrication process for the manufacture of dielectric elastomer soft actuators based on silicone membranes. The three key stages of production are presented in detail: blade casting of thin silicone membranes; pad printing of compliant electrodes; and the assembly of all the components.

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an ...

Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) and Electron Beam Melting (EBM). In spite of its potential processing capability, the direct AM method has several disadvantages such as high cost, poor surface finish of final products, limitation in material selection, high thermal stress, and anisotropic properties of parts. We propose a cost-effective method to manufacture 3D lattice metals. The objective of this study is to provide a detailed protocol on fabrication of 3D lattice metals having a complex shape and a thin wall thickness; e.g., octet truss made of Al and Cu alloys having a unit cell length of 5 mm and a cell wall thickness of 0.5 mm. An overall experimental procedure is divided into eight sections: (a) 3D printing of sacrificial patterns (b) melt-out of support materials (c) removal of residue of support materials (d) pattern assembly (e) investment (f) burn-out of sacrificial patterns (g) centrifugal casting (h) post-processing for final products. The suggested indirect AM technique provides the potential to manufacture ultra-lightweight lattice metals; e.g., lattice structures with Al alloys. It appears that the process parameters should be properly controlled depending on materials and lattice geometry, observing the final products of octet truss metals by the indirect AM technique.

An indirect additive manufacturing method combining a 3D printing of polymers with a centrifugal casting is outlined for manufacturing 3D octet truss metals (Al and Cu alloys) having a unit cell length of 5 mm with a wall thickness of 0.5 mm.

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) ...

A Fabrication Method for Highly Stretchable Conductors with Silver Nanowires

Stretchable electronics are identified as a key technology for electronic applications in the next generation. One of the challenges in fabrication of stretchable electronic devices is the preparation of stretchable conductors with great mechanical stability. In this study, we developed a simple fabrication method to chemically solder the contact points between silver nanowire (AgNW) networks. AgNW nanomesh was first deposited on a glass slide via spray coating method. A reactive ink composed of silver nanoparticle (AgNPs) precursors was applied over the spray coated AgNW thin films. After heating for 40 min, AgNPs were preferentially generated over the nanowire junctions to solder the AgNW nanomesh, and reinforced the conducting network. The chemically modified AgNW thin film was then transferred to polyurethane (PU) substrates by casting method. The soldered AgNW thin films on PU exhibited no obvious change in electrical conductivity under stretching or rolling process with elongation strains up to 120%.

A simple synthesis method is used to chemically solder silver nanowire thin film to fabricate highly stretchable and conductive metal conductors.

Stretchable electronics are identified as a key technology for electronic applications in the next generation. One of the challenges in fabrication of ...

Free-form Light Actuators &#8212; Fabrication and Control of Actuation in Microscopic Scale

Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted researchers&#39; attention in many fields. Most of the studies focused on macroscopic LCE structures (films, fibers) and their miniaturization is still in its infancy. Recently developed lithography techniques, e.g., mask exposure and replica molding, only allow for creating 2D structures on LCE thin films. Direct laser writing (DLW) opens access to truly 3D fabrication in the microscopic scale. However, controlling the actuation topology and dynamics at the same length scale remains a challenge.
In this paper we report on a method to control the liquid crystal (LC) molecular alignment in the LCE microstructures of arbitrary three-dimensional shape. This was made possible by a combination of direct laser writing for both the LCE structures as well as for micrograting patterns inducing local LC alignment. Several types of grating patterns were used to introduce different LC alignments, which can be subsequently patterned into the LCE structures. This protocol allows one to obtain LCE microstructures with engineered alignments able to perform multiple opto-mechanical actuation, thus being capable of multiple functionalities. Applications can be foreseen in the fields of tunable photonics, micro-robotics, lab-on-chip technology and others.

Free-form Light Actuators &amp;#8212; Fabrication and Control of Actuation in Microscopic Scale

Here, we fabricate 3D polymeric micro/nano structures in which both the shape and the molecular alignment can be engineered with nanometer scale accuracy by the use of direct laser writing. Light induced deformation of several types of liquid crystalline elastomer microstructures can be controlled in the microscopic scale.

Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted ...

Fabrication of White Light-emitting Electrochemical Cells with Stable Emission from Exciplexes

The authors present an approach for fabricating stable white light emission from polymer light-emitting electrochemical cells (PLECs) having an active layer which consists of blue-fluorescent poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD) and &#960;-conjugated triphenylamine molecules. This white light emission originates from exciplexes formed between PFD and amines in electronically excited states. A device containing PFD, 4,4&#39;,4&#39;&#39;-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA), Poly(ethylene oxide) and K2CF3SO3 showed white light emission with Commission internationale de l&#39;&#233;clairage (CIE) coordinates of (0.33, 0.43) and a Color Rendering Index (CRI) of Ra = 73 at an applied voltage of 3.5 V. Constant voltage measurements showed that the CIE coordinates of (0.27, 0.37), Ra of 67, and the emission color observed immediately after application of a voltage of 5 V were nearly unchanged and stable after 300 sec.

The authors present a method for fabricating stable white-light-emitting electrochemical cells utilizing emission from exciplexes formed between a blue-emitting fluorene polymer and aromatic amines.

The authors present an approach for fabricating stable white light emission from polymer light-emitting electrochemical cells (PLECs) having an active ...

Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional component that should have high electrical conductivity, high mechanical properties, and high productivity.
In this regard, a carbon fiber/epoxy resin composite can be an ideal material to replace the conventional graphite bipolar plate, which often leads to the catastrophic failure of the entire system because of its inherent brittleness. Though the carbon/epoxy composite has high mechanical properties and is easy to manufacture, the electrical conductivity in the through-thickness direction is poor because of the resin-rich layer that forms on its surface. Therefore, an expanded graphite coating was adopted to solve the electrical conductivity issue. However, the expanded graphite coating not only increases the manufacturing costs but also has poor mechanical properties.
In this study, a method to expose fibers on the composite surface is demonstrated. There are currently many methods that can expose fibers by surface treatment after the fabrication of the composite. This new method, however, does not require surface treatment because the fibers are exposed during the manufacture of the composite. By exposing bare carbon fibers on the surface, the electrical conductivity and mechanical strength of the composite are increased drastically.

A protocol to expose bare fibers on the composite surface by eliminating resin rich area is presented. The fibers are exposed during fabrication of the composites, not by the post surface treatment. The exposed carbon composites exhibit high electrical conductivity in the through-thickness direction and high mechanical property.

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional ...

Fabrication of Ultra-thin Color Films with Highly Absorbing Media Using Oblique Angle Deposition

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present an advanced method for fabricating ultra-thin color films with improved characteristics. The proposed process addresses several fabrication issues, including large area processing. Specifically, the protocol describes a process for fabricating ultra-thin color films using an electron beam evaporator for oblique angle deposition of germanium (Ge) and gold (Au) on silicon (Si) substrates.&#160; Film porosity produced by the oblique angle deposition induces color changes in the ultra-thin film. The degree of color change depends on factors such as deposition angle and film thickness. Fabricated samples of the ultra-thin color films showed improved color tunability and color purity. In addition, the measured reflectance of the fabricated samples was converted into chromatic values and analyzed in terms of color. Our ultra-thin film fabricating method is expected to be used for various ultra-thin film applications such as flexible color electrodes, thin film solar cells, and optical filters. Also, the process developed here for analyzing the color of the fabricated samples is broadly useful for studying various color structures.

We present a detailed method for fabricating ultra-thin color films with improved characteristics for optical coatings. The oblique angle deposition technique using an electron beam evaporator allows improved color tunability and purity. Fabricated films of Ge and Au on Si substrates were analyzed by reflectance measurements and color information conversion.

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present ...

A Soft Tooling Process Chain for Injection Molding of a 3D Component with Micro Pillars

The purpose of this paper is to present the method of a soft tooling process chain employing Additive Manufacturing (AM) for fabrication of injection molding inserts with micro surface features. The Soft Tooling inserts are manufactured by Digital Light Processing (vat photo polymerization) using a photopolymer that can withstand relatively high temperaturea. The part manufactured here has four tines with an angle of 60&#176;. Micro pillars (&#216;200 &#181;m, aspect ratio of 1) are arranged on the surfaces by two rows. Polyethylene (PE) injection molding with the soft tooling inserts is used to fabricate the final parts. This method demonstrates that it is feasible to obtain injection-molded parts with microstructures on complex geometry by additive manufactured inserts. The machining time and cost is reduced significantly compared to conventional tooling processes based on computer numerical control (CNC) machining. The dimensions of the micro features are influenced by the applied additive manufacturing process. The lifetime of the inserts determines that this process is more suitable for pilot production. The precision of the inserts production is limited by the additive manufacturing process as well.

A protocol for fabricating injection molding inserts for complex geometry with micro features on surfaces employing Additive Manufacturing (AM) is presented.

The purpose of this paper is to present the method of a soft tooling process chain employing Additive Manufacturing (AM) for fabrication of injection ...

Fabrication of Microscope Stage for Vertical Observation with Temperature Control Function

Samples are usually placed onto a horizontal microscope stage for microscopic observation. However, to observe the influence of gravity on a sample or study afloat behavior, it is necessary to make the microscope stage vertical. To accomplish this, a sideways inverted microscope tilted by 90&#176; has been devised. To observe samples with this microscope, sample containers such as Petri dishes or glass slides must be secured to the stage vertically. A device that can secure sample containers in place on a vertical microscope stage has been developed and is described here. Attachment of this device to the stage allows observation of sample dynamics in the vertical plane. The ability to regulate temperature using a silicone rubber heater also permits observation of temperature-dependent sample behaviors. Furthermore, the temperature data is transferred to an internet server. Temperature settings and log monitoring can be controlled remotely from a PC or smartphone.

Presented here is a protocol using a temperature-controlled microscope stage that allows a sample container to be mounted on a vertical microscope.

Samples are usually placed onto a horizontal microscope stage for microscopic observation. However, to observe the influence of gravity on a sample or ...