Retailers are hoping to boost sagging U.S. clothing sales by offering new types of fabric that not only look good but also perform functions. The blue jeans of the future will serve to cool you off, warm you up and even resist stains.

These functional products are created through a process known as "nanotechnology," which manipulates individual molecules or groups of atoms to create useful materials or devices.

Glassmakers, for example, use "nanotechnology" to make self-cleaning windowpanes out of tiny particles of titanium dioxide. When these particles interact with ultraviolet waves of sunlight, they loosen dirt. The result is a window that essentially cleans itself.

A treatment called "nanocare" enables manufactures to add microscopic elements that give fabrics new capabilities without changing their appearance. Liz Horner, who is a spokeswoman for Lee Jeans, speaks on the benefits to apparel. "What it does is, at a molecular level, this "nanocare" allows for us to have in these fibers stain repellency, water repellency and wrinkle resistance, while allowing the fabric to remain soft," she says. "So it is not a coated finish. It still looks and feels like your normal khakis, but it brings all these features with it."

The result is "Lee Performance Khakis" pants that resist both stains and wrinkles and are guaranteed to survive through at least 55 home washings.

Liz Horner says this is just the beginning. Clothes of the future, she predicts, will be designed to contain some of the characteristics that can be found today in athletic garments. "In the really extreme sports outerwear, they have the "wicking" fabrics breathable fabrics that pull perspiration away from the body and water away from the body," she says. "People have gotten used to this in their performance (athletic) gear, and they're wanting to bring this into their everyday lives, have it as part of their everyday clothes." Dupont's President of Global Apparel, Bill Ghittes, says his company has created fabrics that can do everything from keeping wearers cool in hot weather, to providing warmth in cold weather. "We call them smart clothes, with multifunctional benefits.? Clothes that can stretch, breathe, providing moisture management and allowing athletes to feel dry next to their skin," he says. "We combine products and brands to bring about a multitude of functionalities that you couldn't get until today."

Looking to the future, Mr. Ghites says that we will eventually wear fabrics that combine textiles and electronics, otherwise known as "textronics."

In five years, he predicts, mountain climbers and skiers will wear jackets with built-in global positioning systems, to enable rescuers to find them in an emergency.