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Textile conservator, Gwen Spicer of Spicer Art Conservation at work

Wednesday, November 1, 2017

Why do polyester fibers attach so well to wool?

Here at Spicer Art Conservation, LLC, we are finishing the treatment of several wool uniforms from several military conflicts. The uniforms were stabilized, then mannequins were custom made for all of them. As all conservators do, we keep our work space clean and tidy, vacuuming on a regular basis. However, no matter what we do, those pesky polyester fibers find themselves on the surface of the wool uniforms. And to make matters worse, they are not easy to remove. Why is this?

White polyester fibers on black wool. Why do they attach so well!?

Well, with my research on magnetic systems, I have been investigating various issues regarding the materials that are frequently placed and used within the magnetic system, other wise known as the "gap". How these materials behave is related to many things, the topography, friction, cohesion, and static charge of the materials. All have an additional influence on how the magnetic system functions. In the mentioned scenario, several of these things have a role.

Where I am going with this, is that when materials are in contact with one another, they share electrons, which assists with the cohesion of materials to one another. The amount of sharing from one material to the other is related to their placement on the Triboelectric series.

The Triboelectric series? What is that?

Well, it is a ranking of materials in the order of their propensity to gain or lose electrons. It is based on the conductivity of the individual materials as seen in the table below. How it works is if two materials in contact are neighbors on the scale, there is less exchange. But if they are far apart, no matter where they lie on the scale, exchange occurs.

Schematic of electron exchange when two different materials are in
contact and then separated. The extent of this exchange is based
on the materials placement on the Triboelectric series.

To go back to the wool uniform and polyester fibers: referencing the chart below, notice how wool is neutral, close to cotton? It is not too often that I find myself trying to remove cotton fibers from wool. But, polyester is far away from neutral on the scale!

So the next time you find yourself complaining about the challenges of polyester fiber removal, do not blame the wool, blame those electrons!
Table: Material order of the Triboelectric series.

Charge
Material
Notes
+++
Air


Polyurethane foam


Hair


Nylon, Dry skin
Dry skin has the greatest tendency to give up electrons and becoming highly positive in charge.

Glass


Acrylic, Lucite

 +
Leather


Rabbit's fur
Fur is often used to create static electricity.

Quartz


Mica


Lead
Surprisingly close to cat fur.

Cat's fur


Silk


Aluminum


Paper


Cotton
Best for non-static clothes

Wool

NEUTRAL



Steel
Not useful for static electricity

Wood
Attracts some electrons, but is almost neutral

Amber


Sealing wax


Polystyrene


Rubber balloon


Resins


Hard rubber


Nickel, Copper


Sulfur


Brass, Silver


Gold, Platinum


Acetate, Rayon


Synthetic rubber


Polyester


Styrene & Polystyrene
Why packing peanuts seems to stick to everything.
 -
Plastic wrap


Polyethylene


Polypropylene


Vinyl, PVC


Silicon


Teflon
Teflon has the greatest tendency of gathering electrons on its surface and becoming highly negative in charge.

Silicone rubber

- - -
Ebonite

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