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About "Ask A Scientist!"

On September 17th, 1998 the Ithaca Journal ran its first "Ask A Scientist!" article in which Professor Neil Ashcroft , who was then the director of CCMR, answered the question "What is Jupiter made of?" Since then, we have received over 1,000 questions from students and adults from all over the world. Select questions are answered weekly and published in the Ithaca Journal and on our web site. "Ask A Scientist!" reaches more than 21,000 Central New York residents through the Ithaca Journal and countless others around the world throught the "Ask a Scientist!" web site.

Across disciplines and across the state, from Nobel Prize winning scientist David Lee to notable science education advocate Bill Nye, researchers and scientists have been called on to respond to these questions. For more than seven years, kids - and a few adults - have been submitting their queries to find out the answer to life's everyday questions.

Previous Week's Question Published: 8 February, 2006 Next Week's Question
Liquid surfactant on dryer sheets coats fabric, eliminating cling
Question
How are dryer sheets manufactured?

Question
Have you ever pulled a load of laundry out of the dryer to find everything stuck together and at least one sock impossible to locate? You probably know that tossing a dryer sheet into the dryer with your wet laundry can eliminate that static cling. But you have probably never given much thought to those familiar sheets of Bounce, Snuggle, or Fresh 'n Soft.

The tumbling action inside of a clothes dryer causes fabrics rubbing against one another to build up electrostatic charges. Positively and negatively charged particles cling together, particularly on synthetic fibers such as polyester or nylon and on permanent press fabrics. Dryer sheets are coated with substances that are released by the heat of the dryer and coat the surface of the fabrics, preventing the static cling. Besides static reduction, dryer sheets are formulated to soften clothes.

Dryer sheets are most often made from a non-woven fabric web of fine polyester fibers, although some are made of polyurethane foam. This substrate material is saturated with a liquid surfactant that cools to a solid coating on the fabric. One side of the surfactant molecule has a positively charged atom that bonds loosely to the surface of negatively charged fabrics. The other side of the surfactant molecule is a long chain fatty material that is left coating the surface of the fabric. That leaves the surface of the fabric just slightly oily, preventing static buildup and making it feel soft. The fatty type molecules on dryer sheets may be quaternary ammonium compounds, sulfate compounds, or silicone derivatives.

Dryer sheets typically contain perfumes to impart fresh smells to clothing, although they are available fragrance-free. Newer formulations renew fabric colors by using compounds called chelants to remove metals from water and dirt which may have built up on fabric surfaces, dulling or changing the color. These features and others can be added so long as they do not interfere with the core static reduction and softening functions of the dryer sheets.

The Internet is full of suggestions for additional uses for used dryer sheets, from reducing static cling on television or computer screens to cleaning soap scum off shower doors or freshening stored clothing. See how you can reuse yours!

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