#foams

A surprising foam discovery could change everyday products

Foams leak not because liquid finds a path—but because the bubbles themselves get out of the way.

Researchers at Tokyo Metropolitan University have uncovered the real reason liquid drains from foams, resolving a long-standing scientific puzzle. Traditional physics models have consistently overestimated how tall a foam must be before liquid begins to leak out. By closely observing foam behavior, the team found that the key factor is not simply liquid moving through a fixed structure, but the pressure needed to rearrange the bubbles themselves. This finding emphasizes how important dynamic processes are when studying soft materials. Anyone who has sprayed foam on a surface has likely noticed droplets forming and dripping from the bottom. This happens because foam is made up of tightly packed bubbles separated by thin liquid films, creating a complex network of pathways. Liquid can move through these pathways, either draining out or being absorbed into the foam when it comes into contact with it. Scientists have long believed that this process is controlled by the "absorptive limit," which depends on "osmotic pressure," a measure of the energy change when bubbles are compressed and the contact area between liquid and gas shifts.

How everyday foam reveals the secret logic of artificial intelligence

Foams don’t just sit still—they behave like a learning AI, constantly reorganizing beneath the surface.

Foams appear in everyday life as soap suds, shaving cream, whipped toppings and food emulsions like mayonnaise. For many years, scientists believed foams behaved much like glass, with their tiny components locked into disordered but essentially fixed positions. New research now challenges that long-standing view. Engineers at the University of Pennsylvania have found that while foams keep their overall shape, their interiors are in constant motion. Even more unexpectedly, the mathematics describing this motion closely resemble deep learning, the technique used to train modern artificial intelligence systems.

Multifunctional flame-retardant foam with strong antibacterial properties developed

A new study combining fire safety, hygiene, and sustainability has led to the development of a multifunctional polyurethane foam that resists flames and suppresses smoke, while also preventing bacterial growth. The new material, which also exhibits improved mechanical properties, could be particularly valuable in hospitals and public transport, among other applications, where fire resistance and antibacterial protection are both critical for safety and health. The research, carried out by Dr. Yingming Li from Chongqing Jiaotong University, and Prof. Dr. De-Yi Wang from IMDEA Materials Institute and the Universidad Francisco de Vitoria in Madrid, introduces a biomass-derived organic aerogel that dramatically enhances the performance of the widely used flexible polyurethane foam (FPUF).

Composite metal foam endures over 1 million load cycles at 400°C and 600°C

New research shows that composite metal foam (CMF) is incredibly resilient at high temperatures, able to withstand repeated heavy loads even at temperatures of 400°C and 600°C. Coupled with the material's high strength-to-weight ratio, the finding suggests that CMF could be used in applications ranging from automobile engines to aerospace components to nuclear power technologies. "CMF has many attractive properties, which make it appealing for a wide range of applications," says Afsaneh Rabiei, corresponding author of a paper on the work and a professor of mechanical and aerospace engineering at North Carolina State University. "But if you want to use a material in engines, airplane parts or any application involving repeated loading and high temperatures, you need to know how the material will perform.

Foam from old mattresses and sponges can now be safely recycled without toxic chemicals

Researchers at the University of Twente have developed a method to recycle polyurethane foam from mattresses and furniture and also household sponges. They did this safely, without using toxic chemicals. The discovery offers a circular solution for millions of tons of hard-to-recycle waste. Polyurethane (PUR), the foam found in mattresses, furniture, and countless other products, typically ends up in landfills or is incinerated after use because it is rarely reusable. Until now, only parts of the foam could be recovered, or a highly toxic substance was needed to recover the building blocks. "For a long time, the use of phosgene, a lethal substance, was the only way to break apart this foam," says Jurriaan Huskens, project leader of the study. "That is simply unacceptable if you really want to use recycling on a large scale."

Nanocellulose-based foam materials for water purification, smart packaging and green electronics

Nanocellulose is a renewable nanomaterial made from plant fibers, with unique properties including lightness, very high strength and large surface area. The doctoral dissertation of Mohammad Karzarjeddi from the University of Oulu, Finland, investigated nanocellulose-based porous foam materials in water purification, smart packaging and wireless communications. These advanced cellulose applications reduce dependence on fossil-based materials. The new dissertation focused on a new generation of lightweight foams called aerogels which can contain air by more than 99% of their weight. The raw material for the foams is nanocellulose made of wood pulp. "Cellulose is converted into hydrogels consisting of thin and strong cellulose nanofibers, which are then dried and then reassembled into aerogels: ultra-light, highly porous solids made mostly of air. Aerogels can be engineered for multiple high-end applications, such as removing pollutants from water, creating smart packaging that reacts to moisture or temperature, and serving as lightweight materials in wireless and radio-frequency telecommunication technologies," Karzarjeddi explains.