Sue Mecham

Sue Mecham grew up inside other people's businesses. Before she was thirteen she had worked in two clothing stores, a sub shop, a restaurant, a health spa and a bar, and she assumed that was simply how life worked. Then her mother finished graduate school, became a PhD polymer chemist and went off to invent materials for a medical-device startup in California, and a teenage Sue decided on the spot that she would get a PhD in polymer chemistry too. As she puts it, that is what she does: she sets a goal and goes and does it.

Mecham earned that doctorate at Virginia Tech and spent about eleven years in industry making things, because she liked making things more than writing papers about them. She ran research groups back at Virginia Tech for the late polymer legend Jim McGrath and at the University of North Carolina, all the while circling the same question: how was she going to start her own company, and around what. She nearly launched a medical-device business out of UNC and pulled back at the last minute, because it did not feel quite right.

Then, in early 2018, Mecham's mother, the Virginia Tech professor Judy Riffle, called with the answer. Riffle had cracked a decades-old problem in her lab: a sulfonated polysulfone that could run reverse osmosis while tolerating chlorine, the one thing the industry-standard polyamide membrane cannot survive. Sue's reply was immediate. She asked her mother whether they should start a company and make chlorine-tolerant membranes together, and Nala Membranes, a genuinely mother-and-daughter polymer venture, was born.

What the two chemists built is, on Mecham's own account, the first new reverse-osmosis membrane material in over forty years: a smooth, chlorine-tolerant film that goes after the biofouling responsible for roughly a quarter of a plant's running costs. It is the kind of deep materials swing an entire industry had decided was impossible, and it has started to collect proof. Nala took the Saudi Water Authority's $100,000 Global Prize for Innovation in Desalination, earned a semifinalist slot in the $119-million XPRIZE Water Scarcity competition, and signed its first multi-year membrane sales agreement. Mecham's framing of why it matters is unfussy: reverse osmosis is too expensive and too limited today, and making it cheaper and simpler could go a long way toward solving the world's water crisis, no matter what happens to Nala itself.

“My mom called me and she said, guess what?... I fixed the problem with the sulfonated polysulfones for reverse osmosis. And we filed a patent today... I said, I think we should make chlorine tolerant reverse osmosis membranes. What do you think? Do you want to start a company with me?”

Her mother hesitated for a moment, then said yes. The rest is a new kind of membrane.