Carbon Nanotube (CNT) Arrays are synthesized by chemical vapour deposition (CVD) systems. Different substrates are coated with nanoparticles of nickel and then introduced to the CVD chamber.
Product Description
Aldrich Materials Science offers multi-walled carbon nanotube (CNT) arrays vertically aligned on either silicon or copper substrates and packaged in a Vacuum Release™(VR) Tray. Select properties of these arrays can be found in Table 1.
|
Product Number
|
Product Name |
Substrate |
Purity |
|
687804
|
Multi-walled Carbon Nanotube Array |
<100> Silicon water |
>99.9% (Carbon Basis) |
|
687812
|
Multi-walled Carbon Nanotube Array |
Copper wafer |
>99.9% (Carbon Basis) |
The VR Tray holds the array securely in place during shipping or handling, offering the ability to release the array on demand. The proprietary Vacuum Release process relies on changing the surface contact area between the array and the Gel membrane on the tray surface. In Retention Mode (Figure 1), the surface contact is maximized and the array is held firmly in place. In Release Mode (Figure 2), the surface contact is minimized by applying a vacuum to draw the Gel membrane away from the array. The array can then be easily removed in the vertical direction using a vacuum tool or tweezers.
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Figure 1. Retention Mode, No Vacuum
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Figure 2. Release Mode, Vacuum Applied
Preparation Instructions - Guidelines for using Vacuum Release Trays
Holding Fixture
The VR Tray should be positioned on a vacuum plate designed to deliver vacuum to the underside of the tray. Stand-alone stations are commercially available however, with proper care applying a house vacuum to the backside of the tray (through the hole in the back of the tray) should also work. Best removal results are obtained by applying a vacuum of 25" of Hg. The Gel membrane may appear to be in the Release Mode even under relatively low vacuum conditions, but a full vacuum is necessary for optimal release.
Pick-up Tools
The largest tweezers tool compatible with the array size should be used in order to deliver the maximum twist or rotation motion. The Gel holding strength is weakest in the peel direction, therefore, the array can be easily removed from the Gel by simply applying rotation.
Array contact/Removal
Contact force between the pick-up tool and the array should be minimized so the array is not pressed into the Gel membrane. Once the array is properly engaged by the pick-up tool, the rate of ascent should initially be slow. Rapid ascent may tend to separate the array from the tool.
Membrane Tear
Gel membranes are relatively fragile and should he handled with care. If a membrane tears, then vacuum leakage at the tray will occur, which can inhibit array removal.
Vacuum Release is a trademark of Gel-Pak. Figures courtesy of Gel-Pak.
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This information has been sourced, reviewed and adapted from materials provided by Sigma Aldrich.
For more information on this source, please visit Sigma Aldrich.