Name: a simple and scalable fabrication method for organic electronic devices on textiles
Uploaded: 2017-03-13T15:00:00
Description: Watch this Scientific Journal Video about A Simple and Scalable Fabrication Method for Organic Electronic Devices on Textiles at JoVE.com

The authors would like to acknowledge the BPI PIAVE AUTONOTEX grant for the financial support.

1. Patterning Conducting Polymers on Textile
<ol>
	<li>Fix a 10 cm x 10 cm textile sheet on a planar surface for easy handling during the process. For the textile, use a 100% interlock knit polyester fabric with a thickness of 300 &#181;m and a knit direction stretch capability up to 50%.</li>
	<li>To make a mask containing the patterning design, use a 125 &#181;m-thick polyimide film; an example of the pattern is illustrated in Figure 1.
	<ol>
		<li>Use a laser cutter (e.g., Protolaser S, LPK...

<ol>
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The patterning of conducting materials is one of the first steps in the fabrication of functional electronic devices. This can become challenging, as the fabrication process needs to take into account the chemical and physical properties of such materials, and the process flow needs to consider the material cross-compatibility between the fabrication steps. In the microfabrication of organic electronic devices, these two aspects are even more significant due to the highly reactive nature of organics. Today, however, orga...

The field of wearable electronics is a fast-growing market expected to be worth 50 billion euros in 2025, over three times the current market. The main challenge facing current wearable devices is that intrusive solid electronic attachments limit the usage of established devices in wearable systems. Using textiles that are already present in everyday life is a very attractive and straightforward approach to avoid this limitation. Due to its elastic capability, some parts of the clothing that we wear are naturally in tight contact with the skin. Many examples of smart clothes available on the market today are based on thin, plastic displays, keyboards, and light source devices embedded in textiles, linking electronics with humans in a fashionable way1. In sport practice, health monitoring relies on textile electrodes, which offer comfortable alternatives to commonly used adhesive electrodes and metal wristbands. Here, conductive fibers are directly integrated with stretchy fabrics to prevent skin irritation and other discomforts during extended wear. Additionally, textiles offer a number of opportunities to integrate curvature sensors to capture motion2, to integrate shear sensors for the development of functional robotic actuators3, and certainly to integrate biosensors through the detection of an analyte in sweat4.
Modern wearable technology relies on carbon-based semiconductor materials that deliver electronic devices with unique properties. The &#34;soft&#34; nature of organics offers better mechanical properties for interfacing with the human body compared to traditional solid-state electronics. This mechanical compatibility, paired with mechanically flexible substrates, enables the use of non-planar form factors in devices such as textiles. The use of organics is also relevant in life sciences due to their mixed electronic and ionic conductivity5. Besides, organic semiconducting and optoelectronic materials empower a large variety of functional devices with display, transistor, logic, and power capabilities6,7,8,9. The main difficulty in the fabrication of such organic devices is the controlled deposition of functional materials on the non-planar surfaces of textiles. Conventional microfabrication techniques are primarily limited by the incompatibility of the deposition process with the structural dimensionality of textile substrates.
Here, we describe a simple and scalable fabrication protocol that allows for the selective deposition of conducting polymers on structured textiles. The presented process enables the fabrication of wearable and conformal electronic devices. The approach is based on the patterning of the commercially available conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and an elastomeric stencil material polydimethylsiloxane (PDMS) on textile. This combination allows for the efficient confinement of the aqueous PEDOT:PSS solution, as well as for the retention of the soft and stretchable properties of textiles. This simple and reliable fabrication method paves the way for the fabrication of a variety of electronic devices directly on textiles in a cost-efficient and industrially scalable manner.

<table border="0" cellpadding="0" cellspacing="0" width="748">
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	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">SYLGARD 184, Silicone elastomer kit (Base and Curing agent)</td>
			<td style="width:159px;">Dow Corning</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">PDMS elastomer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;"></td>
			<td style="width:159px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="4" height="21" style="height:21px;width:748px;">The conducting polymer formulation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">CleviosTM PH 1000 PEDOT:PSS</td>
			<td style="width:159px;">Heraeus</td>
			<td style="width:119px;"></td>
			<td>Conductive polymer</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">Ethylene glycol</td>
			<td style="width:159px;">Sigma-Aldrich</td>
			<td style="width:119px;">03750-250ML</td>
			<td>Solvent (EG), CAS: 107-21-1</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">3-methacryloxypropyltrimethoxysilane</td>
			<td style="width:159px;">Sigma-Aldrich</td>
			<td>M6514</td>
			<td>Cros linker (GOPs), CAS: 2530-85-0</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">4-dodecylbenzenesulfonic acid</td>
			<td style="width:159px;">Sigma-Aldrich</td>
			<td style="width:119px;">44198</td>
			<td>(DBSA), CAS: 121-65-3</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;"></td>
			<td style="width:159px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="4" height="21" style="height:21px;width:748px;">The ionic liquid gel</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">UV lamp DFE 2340</td>
			<td style="width:159px;">C.I.F/ ATHELEC</td>
			<td style="width:119px;">DP134</td>
			<td>UV-365nm</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">1-Ethyl-3-methylimidazolium ethyl sulfate</td>
			<td style="width:159px;">Sigma-Aldrich</td>
			<td style="width:119px;">51682-100G-F</td>
			<td>Ionic Liquid (IL), CAS: 342573-75-5</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">Poly(ethylene glycol) diacrylate</td>
			<td style="width:159px;">Sigma-Aldrich</td>
			<td style="width:119px;">455008-100ML</td>
			<td>Mn 700, CAS: 26570-48-9</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">2-Hydroxy-2-methylpropiophenon</td>
			<td style="width:159px;">Sigma-Aldrich</td>
			<td style="width:119px;">405655-50ML</td>
			<td>Phot Initiator (PI), CAS: 7473-98-5</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;"></td>
			<td style="width:159px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;"></td>
			<td style="width:159px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">The textile fabric</td>
			<td style="width:159px;">VWR</td>
			<td style="width:119px;">Spec-Wipe 7 Wipers</td>
			<td>100% interlock knit polyester fabric</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">The polyimide film</td>
			<td style="width:159px;">DuPont</td>
			<td style="width:119px;">HN100</td>
			<td>Polyimide film with 125 &#181;m thickness</td>
		</tr>
	</tbody>
</table>

a simple and scalable fabrication method for organic electronic devices on textiles

Today, wearable electronics devices combine a large variety of functional, stretchable, and flexible technologies. However, in many cases, these devices cannot be worn under everyday conditions. Therefore, textiles are commonly considered the best substrate to accommodate electronic devices in wearable use. In this paper, we describe how to selectively pattern organic electroactive materials on textiles from a solution in an easy and scalable manner. This versatile deposition technique enables the fabrication of wearable organic electronic devices on clothes.

Traditional methods for applying colors or patterns to textiles rely on removable masking layers to allow the selective deposition of dyes. In Figure 1, we show the adaptation of such an approach to the patterning of PEDOT:PSS electrodes on textiles. As a masking layer, we used hydrophobic polydimethylsiloxane, which can restrain the non-controllable diffusion of the aqueous PEDOT:PSS solution. Moreover, the softness and stretchability of knitted and woven textiles can be...

Watch this Scientific Journal Video about A Simple and Scalable Fabrication Method for Organic Electronic Devices on Textiles at JoVE.com

A Simple and Scalable Fabrication Method for Organic Electronic Devices on Textiles

In this paper, we present a protocol to selectively deposit organic materials on textiles, which allows for the direct integration of organic electronic devices with wearables. The fabricated devices can be fully integrated in textiles, respecting their mechanical appearance and enabling sensing capabilities.

Today, wearable electronics devices combine a large variety of functional, stretchable, and flexible technologies. However, in many cases, these devices ...

The overall goal of this patterning procedure is to selectively deposit organic electroactive materials on textiles, which enables the fabrication of wearable organic electronic devices directly on clothing. This method can help to answer a key question in the field of wearable electronics, especially how to seamlessly integrate electronics with clothing to interact efficiently with the human body. The main advantage of this technique stems from elastic capability of textiles, which allows to worn this textiles comfortably in the close contact with the skin.First an idea of this method. When we look for a nontraditional way of combining organic electronics with textiles platform in a cost-efficient and industry scalable manner. This technique was inspired by old Japanese kimono dying technique, which we adapted for today's micro-fabrication tools and environment.To begin the procedure, use a laser cutter to cut a pre-designed electrode pattern into a 125-micrometer-thick polyamide sheet to form a mask. Then take a 300-micrometer-thick sheet of 100%interlock knit polyester fabric with a knit direction stretch capability of up to 50%Secure this to a flat, portable surface. In a fume hood, use an automatic tape casting tool to coat the polyamide mask with a polydimethylsiloxane formulation at six meters per minute to a wet film thickness of 200 micrometers.Gently place the fabric on the PDMS-coated mask and allow the PDMS to be absorbed into the textile structure for 10 minutes. Anneal the PDMS at 100 degrees Celsius for 10 minutes or at 60 degrees Celsius for 20 minutes for heat-sensitive fabrics. In the fume hood, mix together 80 milliliters of PEDOT:PSS dispersion, 20 milliliters of ethylene glycol, 40 microliters of 4-dodecylbenzenesulfonic acid, and one milliliter of 3-propylmethacrylate.Then place the mixture to stir on a magnetic stirrer. Brush coat the PEDOT:PSS mixture over the masked fabric until the electrode pattern is coated with about one milliliter of the mixture per centimeter squared and appears to be uniform in color. The brush coating step of PEDOT:PSS is the critical step.The sheet resistance of the pattern needs to be about 230 ohm square. Remove the polyamide mask then cure the electrode pattern at 110 degrees Celsius for one hour or at 60 degrees Celsius for two hours for heat-sensitive fabrics. To fabricate cutaneous electrodes from PEDOT:PSS electrodes on textiles, first prepare a gel mixture composed of 60%by volume ionic liquid, 35%crosslinking agent, and 5%photoinitiator.In a fume hood, coat the electrodes with 20 microliters per centimeter squared of the ionic liquid, and then add 25 microliters per centimeter squared of the gel mixture by drop casting. Expose the coated electrodes to 365-nanometer UV light for 10 to 15 minutes to solidify the gel and form the cutaneous electrodes. To fabricate capacitive sensors from PEDOT:PSS electrodes on textiles, in a fume hood, apply 10 to one PDMS formulation to the fabric.Use a squeegee to evenly spread the PDMS formulation over the electrodes to remove any excess. Anneal the insulating layer of the PDMS at up to 100 degrees Celsius for at least 10 minutes, depending on the heat tolerance of the fabric, to form the capacitive sensors. Using this method, PEDOT:PSS electrodes were patterned on knit and woven textiles.The patterning resolution of knitted polyester is greater than one millimeter. Narrower resolutions can be obtained on tightly knit or woven textiles. The electrodes patterned on knit textiles function as stretch sensors with no further modifications.When the fabric is stretched, the twisting of the conductive fibers results in a change in the resistivity. An organic electrochemical transistor array was patterned onto a woven nylon ribbon, a wearable sweat sensor, also with no further modifications. The addition of an ionic liquid in gel allowed the electrodes to function as wearable cutaneous electrodes for electro-physiological monitoring.Alternatively, the addition of an insulating PDMS layer created capacitor sensors. Touching the electrodes causes a capacitance change, allowing fabrication of a wearable keyboard. The combination of close-fitting textiles with organic and soft electrodes offers an improved communication channel with the human body while compared to the traditional solid-state electronic device.This method allows for the future customization of existing garments with the smart electronic devices. However, one of the critical and in some cases limiting points of this technology is that materials, organic materials'durability and wearable conditions.

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