(University of California, Davis) —Locker rooms and student dorms
everywhere could soon be a little more fragrant, thanks to an
invention by University of California, Davis, textile chemist
Gang Sun: odorless sports socks. The same technology could be
used to make everything from odor-free diapers to hospital gowns
that repel bacteria and viruses.
"Textiles make great media for growing bacteria," says Sun. Bacteria and
yeasts in clothing break down perspiration, which has little odor by itself, and
cause the all too familiar rank smell.Sun himself says he wore the socks for a couple
of days, with no obvious smell. After use, the socks need only a machine wash with
household chlorine bleach to recharge the bacteria-killing capacity, says Sun.
The technology works by attaching chlorine-containing molecules called halamines
to textile fibers, using a method patented by Sun. Chlorine in the form of halamines
has powerful bacteria-killing properties, used for example to disinfect swimming
pools. Unlike chlorine gas, there are no adverse effects as toxic chlorinated carbon
atoms are not generated.
By sticking halamines to the cellulose fibers in cotton, the bacteria-killing effect
can be bonded to the material and used again and again. Eventually, the chlorine
is used up and can be regenerated with a wash in chlorine bleach.
The key to this invention was finding a practical way to bind
the halamines to the cotton. "Obviously, one limitation is that you can't destroy the fabric during
manufacture," says Sun. The finished product has to be as robust as regular
textile, and the process has to be economical. Ease of manufacture is another important
factor. Most cotton mills use a durable press treatment, and halamine treatment can
be added at this stage with minimal modification, according to Sun.
Commercial development of these bacteria-killing textiles into
garments is licensed by the University of California to Seattle-based
company HALOSOURCE Corporation. The technology is being developed
for a number of applications, according to Kent Foster, HALOSOURCE
director of marketing and business development. These include
single-use products, such as diapers and incontinence pads, and products for multiple
use such as sportswear, kitchen tools and microbe-resistant uniforms for hospital
or prison staff.
One important application could be in hospital uniforms. Hospital
infections are an increasing problem, and hospitals are trying
to find ways to prevent infections spreading from patient to
patient, says Sun. Medical worker uniforms might be important
in spreading infection, by carrying microbes from one patient to another. Uniforms
that could kill any bacteria or viruses landing on them might be a useful tool to
prevent the spread of infection, he says.
Since the halamine treated fabrics kill microorganisms almost
instantly on contact, Sun believes that these materials are
best suited for medical uses such as uniforms, wipes, bedding
and towels.
HALOSOURCE is currently involved in technical evaluations, and
discussions of product plans are under way with a number of
manufacturers, says Foster. "HALOSOURCE
is working with some of the largest companies in consumer product areas, air filtration
and uniforms," says Foster. "These companies have approached us as a result
of publications by Sun," he says, adding that Sun has played a key role in developing
relationships with manufacturers. "Sun is very practical in getting from the
lab to a manufacturing environment," says Foster.
HALOSOURCE is working with the grower-supported development and
marketing company Cotton
Incorporated on validation of halamine technology. "Cotton Inc.
has made its pilot manufacturing facility in North Carolina available for prototyping
and scale-up trials," says Foster. Sun was instrumental in bringing Cotton Inc.
into contact with HALOSOURCE, according to Foster.The odor-free socks have been tested
by volunteers, including the UC Davis cross-country running squad. Coach Sue Williams
says that the men and women of the squad tested the socks through one full workout,
including an eight or nine mile run. "They had pretty hard use for a day," says
Williams. "They were comfortable, not irritating, and smelt very mildly of chlorine
before and after," she says. "After an eight- or nine-mile run, for socks
not to smell of feet is a real bonus," she adds.
Sun began his work at China Textile University, Shanghai, where
he taught polymer chemistry. He moved to Auburn University, Alabama,
in 1989 to study for a Ph.D. in organic chemistry. While developing
polymer disinfectants for self-cleaning air filters, he became
interested in disinfectants and in ways of binding them to textile
polymers. He has continued to collaborate with the Department of
Textiles Engineering at Auburn University since coming to UC Davis
in 1994
