This scientist is using nanotechnology to build a better menstrual pad

Dec 28, 2023

The average Western woman will use tens of thousands of pads and tampons during her life. But that number is dramatically different in India, where only around 12 percent of women have access to disposable menstrual products.

That number came as a shock to Chandra Shekhar Sharma, a nanotechnologist interested in the absorptive properties of menstrual pads. With the help of the women in his department at the Indian Institute of Technology in Hyderabad, he set out to make a better pad — an innovation that may change the way women see their periods in a country known for its menstrual stigma.

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"In Indian society, it's not so easy to discuss menstrual periods," says Sharma. When he first floated the idea of figuring out how to make a more absorbent, less expensive pad to his students, he was met with deafening silence. So he brought it up again to another class the next year. This time, a student named Shital Yadav dared to take on the project with him. Together, they braved the hard conversations and the even harder task of rethinking the materials that make up sanitary products. The result, as they describe it in the journal Applied Materials Today, is an entirely new type of fibers designed with women's periods in mind.

Most modern pads rely on superabsorbent polymers (SAPs), a genre of gels that are added to the napkins’ cellulose fiber cores to make them thinner and more absorbent than ever before. But SAPs, which are fondly nicknamed "super slurpers" by materials scientists, have a few serious downsides. Not only are they petroleum-based, taking centuries to degrade in landfills, but they’ve been linked with toxic shock syndrome. Tampons haven't been made with SAPs for years.

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Sharma, Yadav and their co-authors hypothesized that nanofibers might be able to step in at the core of pads produced sans SAPs. First, they analyzed commercially available maxi pads and assessed their composition. Then they used a technique called electrospinning — in which an electric field is applied to a solution of nanoparticles — to create three types of fibers, one of which didn't contain SAPs.

"Commercial products have very thick fibers," Sharma says. The average pad contains fibers about as thick as a human hair. The team's non-SAP fibers were 200 times thinner than those contained in commercially available pads — about 150 nanometers thick. That translated to more surface area, more porousness, and better liquid absorption.

When the team compared their new materials to their commercial counterparts, they found that all three absorbed more liquid. But the effect was most pronounced in the material that didn't contain any SAPs. That material also held up better under liquid loads, left behind less residue, and was more comfortable to the touch. The team concluded that their new electrospun material could replace SAP options altogether.

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That's good news for people who use pads, Sharma says. By eliminating SAPs, manufacturers could one day make more absorptive pads with fewer chemicals for less money. That could make a real difference to Indian women, many of whom use materials like rags, ashes and even sand to soak up their menstrual blood instead of purchasing disposable products.

The lack of affordable menstrual products is more than just an inconvenience: Over 20 percent of Indian girls report missing school because of menstruation, and Indian women in the workforce report missing an average of 2.2 days of work per menstrual period. It also can cause serious health problems for women at risk of developing reproductive tract infections due to lack of hygiene.

Sharma's not the only Indian man wading into the menstrual fray. In 1998, a man named Arunachalam Muruganantham noticed his new wife collecting discarded rags and newspapers to soak up her menstrual flow and invented a machine to help women produce their own cheap pads for a fraction of the cost.

Unlike Muruganantham, who is now known as India's "Menstrual Man," Sharma didn't initially get into the pad game to change the conversation about women's periods. Instead, he was drawn to the project because of his fascination with the absorptive potential of nanomaterials. But with the help of his female students and his wife, he learned more about the challenges of menstruating women in India and began to realize that better pads are more than, as he puts it, "solving the problem of the common man."

Next, Sharma and his students will work on ways to commercialize a product that could one day make menstruation easier and more affordable for Indian women and girls. "This technology is going to benefit a large section of the society," he says. "This is the 21st century and women are still struggling."

Erin Blakemore (@heroinebook) is a freelance journalist from Boulder, Colo. She is the author of "The Heroine's Bookshelf" (Harper).

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