New Textiles 2010

I wanted to develop materials that could be used in combination with the electro-magnetic yarn I developed last week. These silicone fabrics are still in the vein of developing fabrics that move as they will 'leap' into place in response to either permanent magnets or electromagnets.

After laying down wax paper, I constructed 1 cm tall walls of clay that served for the mold for the triangular piece. I then made cylinders out of the clay and placed them within the triangle so that i could combine the two mixtures of silicone into one piece. I also arrange magnets of various sizes within the mold.

I then measured out 40 mL of the first part of the silicone and stirred 1 tablespoon of carbonyl iron into it. In another cup a mixed together both parts of the silicone rubber to make 80 mL of pure silicone rubber solution. I then poured this mixture into the triangular mold. As that was curing ( it has a 4-6 minute work time) I mixed 40 mL of the second part of the silicone in with the first cup and carbonyl iron. I stirred it together for at least one minute to be sure that the solution was well mixed. I then poured this into the rings that I had made for the spots. The excess I poured into an aluminum foil mold. I then removed the clay cylinders so that the two silicone mixtures could cure together. I then let both pieces to cure for 30 minutes.

When I was sure it had cured, I removed it from my mold. Because the mold was clay, I did not have any problems with this step. Unfortunately it became clear that my piece was too thin to contain the magnets and even though they were successfully encased, they soon ripped out of the rubber in favor of sticking to the ferromagnetic parts or each other. I removed the rest to protect the piece.

The original design for the triangular piece incorporated neodymium magnets into the silicone rubber. After fabrication magnets did stay within the rubber. However, upon demonstrating the snap on feature of the magnet corner to the spots, the magnet ripped out of the rubber. Therefore more thought must go into incorporating the magnets into the piece, perhaps they might be included within a small bag tied to the piece or threaded onto some string. This would prevent tearing.

The attractiveness of these fabrics are only in their utility and so finding applications for these materials are key to their development and popularity. I am open to suggestions as I ponder the last two assignments.

Incorporating carbonyl iron particles with silicone rubber leads to a flexibly ferromagnetic fabric. We demonstrate making the entire fabric magnetic or just spots with two pieces. We take advantage of the softness of the silicone rubber to turn non-magnetic surfaces like glass into temporarily magnetic surfaces.

• Large Area (12 in x 12 in equilateral triangle and 6in diameter blob)
• Incorporation of ferromagnetic material in spots or entirely
• Takes advantage of both silicon rubber and carbonyl iron filler properties
• Future incorporation of magnets

Silicone rubber

The original design for the triangular piece incorporated neodymium magnets into the silicone rubber. After fabrication magnets did stay within the rubber. However, upon demonstrating the snap on feature of the magnet corner to the spots, the magnet ripped out of the rubber. Therefore if incorporating multiple magnets they might be included within a small bag tied to the piece or threaded onto some string. This would prevent tearing.

Ferromagnetic Fabrics

Incorporating carbonyl iron particles with silicone rubber leads to a flexibly ferromagnetic fabric. We demonstrate making the entire fabric magnetic or just spots. We take advantage of the softness of the silicone rubber to turn non-magnetic surfaces like glass into temporarily magnetic surfaces.

Features:

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Magnetic Yarn

These yarns seem to have a mind of their own!

Yarn

1. Magnetic Yarn
2. Electromagnetic Yarn: Prototype 1
3. Electromagnetic Yarn: Prototype 2

Magnetic Yarn (MY)Features:

• Cotton, Steel Fibers, and Neodymium Magnets
• Over the 18in length, the yarn is insulating. However because of 1 inch conductive (10-100 ohm) patches, the yarn's resistance is sensitive to posture and internal connection.
• Can be attached to any ferromagnetic surface (like your refrigerator)

Electromagnetic Yarn: Prototype 1 (EMY1) Features:

• Cotton, and Coated Copper Wire
• Electromagnets lend themselves well to the form factor of yarn and this 23 inch cord featuring 21 "beads" of coiled copper will behave as one.
• Over 2500 coils with area <20mm^2!
• Electromagnets can be re-oriented to direct field lines conveniently.
• Copper wire allows high current without burning up
• Actuation (bunching) may be possible

Electromagnetic Yarn: Prototype 2 (EMY2) Features:

• Cotton, Steel Fibers, Coated Copper Wire, and Neodymium Magnets
• Conceptually bunching and unbunching possible
• In development:
  • 6 in. yarn incorporating all above materials
  • 36 in. silicone dip-coated conductive thread

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Motivation

Re-imagining the fundamental yarns of a textile provides an opportunity to think about embedded intent and actuation schemes. We have seen in class materials that sense and communicate, but what about textiles that 'do' ? Nitinol wire has traditionally been the first approach to this question, but large switching times and required currents continue to be obstacles to adoption. Here we explore the first steps of incorporating magnetic components as an eventual alternative.

Construction

MY: Two spun strands were twisted, one entirely cotton and the other cotton, alternating with steel wool or steel wool with small magnet. After being twisted together, additional cotton and steel wool were added around both strands to help with cohesion and keeping the magnets in place.

EMY 1: Cotton balls were unrolled and laid on top of each other with ends fanned out. The cotton was then hand spun by twisting an S twist. Copper wire was then twisted as a Z twist and coiled ~120 times every few centimeters. The entire piece has a resistance of less than 30 ohms. The entire yarn is insulated and is only conductive end to end.

Note that a .5 T magnet did interact with the electomagnet enough to pick up the end when the current through the yarn was approximately 600 mA.

EMY2: Conductive thread was dip coated in a polymerizing silicone rubber and was removed after 6,7, and 8 minutes respectively. This was done to determine whether this could be a viable option to replace the coated copper wire. This has been ruled out for the time being. Techniques from MY and EMY1 were combined, unfortunately unsuccessfully. THe magnets selected were too strong and the yarn would not remain in the desired static position.

Opportunities for Improvement

With its short fibers and ease of untwisting, cotton proved challenging to use. We hypothesize that the electromagnetic would be stronger if the coils were around a ferromagnetic material rather than an air core. Fortunately our work with steel wool puts us in a good position to test this theory within the next iteration. Incorporating permanent magnets should be delayed until order of magnitude estimates are completed to determine sizing.