Every year, petroleum-based feedstocks are used worldwide to make roughly 3 billion flip-flops, the rubbery, flat-sole sandals held on the foot by a Y-shaped strap that fits between the first and second toes.
It might seem like a throwaway product—and it is, according to Stephen Mayfield, a UC San Diego professor of biology and director of the California Center for Algae Biotechnology. The petrochemicals used to produce flip-flops make them impervious to the elements—and they end up as non-biodegradable rubbish in rivers and oceans, and in landfills and trash heaps.
Yet flip-flops also are the No. 1 shoe in the world. “These are the shoes of a fisherman and a farmer,” Mayfield says. “This is the No. 1 shoe in India, the No. 1 shoe in China, and the No. 1 shoe in Africa.”
So Mayfield and colleagues at UC San Diego recently unveiled prototype flip-flops made from algae-derived polymeric polyols instead of petroleum-based polyurethanes. The idea is to offer consumers more environmentally friendly flip-flops, made with renewable materials and perhaps even biodegradable after a year or two.
Mayfield, who was a scientific co-founder of the unsuccessful algal biofuel company Sapphire Energy, worked with UC San Diego chemists Michael Burkart and Robert “Skip” Pomeroy to make a pliable foam from algae-based polyols that could replace conventional polyurethanes.
To advance the commercial prospects for biodegradable flip-flops, Mayfield, Burkart, and Pomeroy founded an industrial biotech, Algenesis Materials, in early 2016.
“Our goal is to get to 100 percent renewable, and 100 percent biodegradable,” said Mayfield, who is an environmentally conscious surfer and coastal enthusiast. “Burkart’s convinced that we’re going to throw these [flip-flops] in a compost pile, and in six months they’ll be gone. But we’re not there yet.”
About half of the material used to make the current prototype is renewable, Mayfield said. But it will take time to assess how biodegradable the flip flops are in the environment.
Some UC San Diego students who worked on the R&D are also working at Algenesis. “It’s an opportunity to teach the grad students how to start a company,” Mayfield said. “The undergrads are just on fire for this project.”
The co-founders put in their own money to fund the startup. “We have not taken any venture money, primarily because we didn’t have to,” Mayfield said. To begin commercial production, though, would likely require raising some venture capital. To introduce sustainable flip-flops into emerging markets would require manufacturing at scale for about $3 a pair, Mayfield said. (Or perhaps at a cost even lower than that, as flip-flops are for sale at Old Navy between $2.50 and $4 a pair.) They plan to make flip-flops that are sustainable and biodegradable available for sale within the next year.
“I’m still really hesitant to go to venture companies [for funding],” Mayfield said. “Shoe companies are totally driven by what’s trendy, and renewable is very trendy right now.”
Mayfield said he doesn’t want to see their goals subverted by competing goals to make a quick profit. “If the only thing that comes out of this is that I get biodegradable flip-flops into the market, that would be the greatest success of my life,” he said.
