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 with two pieces. We take advantage of the softness of the silicone rubber to turn non-magnetic surfaces like glass into temporarily magnetic surfaces.

Features:

  • 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

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Motivation

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.

Construction

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.

Opportunities for Improvement

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.