Watch This Liquid Membrane Filter Let Big Stuff Through and Keep Small Stuff Out

This mind-melting filter works in the opposite way that you would expect.
September 6, 2018, 12:59pm
Screenshot: YouTube/Science Magazine

Science fiction is full of portals and membranes that separate people, universes, and dimensions. (Remember the fleshy ones in Stranger Things that led to the Upside Down?)

Sadly, space-time portals are relegated to the imagination. But a new type of membrane is perhaps equally as cool, and offers practical, real-world applications.

A team of researchers at Pennsylvania State University created a novel, self-healing membrane. Unlike a coffee filter, through which liquid percolates and grinds are contained, the membrane works in reverse by allowing larger particles to pass through, while keeping smaller ones at bay, and words really don’t do it justice.

The membrane was inspired by endocytosis, according to a paper published last month in Science. Endocytosis is the process by which cells envelop and transport molecules—giving researchers the idea for a self-healing solution that can be penetrated by particles without leaving a permanent hole.

During tests, the membrane contained a swarm of fruit flies, and sealed gas within a tube while letting other objects through (leading the team to suggest its potential for “odor control.”). It also blocked contaminants during a simulated surgery “without inhibiting visibility or in-film maneuverability,” the paper stated.

The solution was made from two components: deionized water and sodium dodecyl sulfate (SDS), a surfactant found in shampoo and other beauty products. And by adjusting the concentration of SDS, the membrane’s surface tension could be calibrated. For example, higher levels of tension only permitted larger, faster moving particles to pass through. But at lower levels, smaller, slower moving particles could do the same.

The team hopes that more physically sturdy membranes can be experimented with, according to their study. And with more research, they’re confident that liquid membranes will “open up novel and creative technological applications in medicine, waste management, pest and disease control, and other applications.”