Stanford

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory have recorded the most detailed atomic movie of gold melting after being blasted by laser light. The insights they gained into how metals liquefy have potential to aid the development of fusion power reactors, steel processing plants, spacecraft and other applications where materials have to withstand extreme conditions for long periods of time.

Produced by plants, algae and some bacteria, cellulose is an abundant molecule involved in the production of hundreds of products, from paper to fabrics to renewable building materials. It’s also one starting material for producing ethanol, a common fuel additive and renewable fuel source. Now, Stanford scientists have found a new type of cellulose in bacteria with properties that could make it an improvement over traditional cellulose for fuels and other materials, or for better understanding and treating bacterial infections.

Stanford researchers have developed a reversible fabric that, without expending effort or energy, keeps skin a comfortable temperature whatever the weather. In a paper published in Science Advances, a team led by Yi Cui, professor of materials science and engineering, created a double-sided fabric based on the same material as everyday kitchen wrap. Their fabric can either warm or cool the wearer, depending which side faces out.

The next generation of feature-filled and energy-efficient electronics will require computer chips just a few atoms thick. For all its positive attributes, trusty silicon can’t take us to these ultrathin extremes. Now, electrical engineers at Stanford have identified two semiconductors – hafnium diselenide and zirconium diselenide – that share or even exceed some of silicon’s desirable traits, starting with the fact that all three materials can “rust.”

Stanford University engineers have developed dynamic windows that can switch from transparent to opaque or back again in under a minute, a significant improvement over dimming windows currently being installed to reduce cooling costs in some buildings. Stanford engineers have built a smart window that quickly changes from clear to dark and back again depending on the light.

High pressure could be the key to making advanced metal mixtures that are lighter, stronger and more heat-resistant than conventional alloys, a study by Stanford researchers suggests. Humans have been blending metals together to create alloys with unique properties for thousands of years. But traditional alloys typically consist of one or two dominant metals with a pinch of other metals or elements thrown in. Classic examples include adding tin to copper to make bronze, or carbon to iron to create steel.

Plastic objects made by injection molding are abundant and, for many of us, a constant presence in our everyday lives. Your phone case, toothbrush and the keys on your computer are all probably the result of mass production, which involves injecting molten plastic into molds. In an advanced design and manufacturing course, students learn that the ubiquitous plastic objects made by injection molding are deceptively hard to make.

For 60 years computers have become smaller, faster and cheaper. But engineers are approaching the limits of how small they can make silicon transistors and how quickly they can push electricity through devices to create digital ones and zeros. That limitation is why Stanford electrical engineering Professor Jelena Vuckovic is looking to quantum computing, which is based on light rather than electricity.

As electronics become increasingly pervasive in our lives – from smart phones to wearable sensors – so too does the ever rising amount of electronic waste they create. A United Nations Environment Program report found that almost 50 million tons of electronic waste were thrown out in 2017—more than 20 percent higher than waste in 2015. Troubled by this mounting waste, Stanford engineer Zhenan Bao and her team are rethinking electronics.

Behind its thick swirling clouds, Venus is hiding a hot surface pelted with sulfuric acid rains. At 480ºC, the planet’s atmosphere would fry any of today’s electronics, posing a challenge to scientists hoping to study this extreme environment. Researchers at the Stanford Extreme Environment Microsystems Laboratory, or the XLab, are on a mission to conquer these conditions.

The brain is soft and electronics are stiff, which can make combining the two challenging, such as when neuroscientists implant electrodes to measure brain activity and perhaps deliver tiny jolts of electricity for pain relief or other purposes. A robotic test instrument stretches over a curved surface a nearly transparent, flexible electrode based on a special plastic developed in the lab of Stanford chemical engineer Zhenan Bao.

  Scientists at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory have discovered a way to use diamondoids – the smallest possible bits of diamond – to assemble atoms into the thinnest possible electrical wires, just three atoms wide.

Writing in the Proceedings of the National Academy of Sciences, a team led by Eric Appel, an assistant professor of materials science at Stanford, and doctoral candidate Anthony Yu describe how to make a generation of hydrogels based on abundant natural materials. The hydrogels incorporate two abundant and inexpensive basic ingredients. One is a cellulose polymer derived from natural sources such as wood chips and agricultural waste.

A nanosize squeeze can significantly boost the performance of platinum catalysts that help generate energy in fuel cells, according to a new study by Stanford scientists. The team bonded a platinum catalyst to a thin material that expands and contracts as electrons move in and out, and found that squeezing the platinum a fraction of a nanometer nearly doubled its catalytic activity. The findings are published in the journal Science.

Stanford researchers, studying a tiny device that has become increasingly important in disease diagnostics and drug discovery, observed the surprising way it funneled thousands of water droplets into an orderly single file, squeezing them drop by drop, out the tip of the device. Instead of occurring randomly, the droplets followed a predictable pattern.

A theory developed by the late Stanford professor and Nobel laureate Felix Bloch suggested that a specially structured material that allowed electrons to oscillate in a particular way might be able to conduct terahertz signals. Now, decades after Bloch's theory, Stanford physicists may have developed materials that enable these theorised oscillations, someday allowing for improvements in technologies from solar cells to airport scanners. The group published their findings in Science.

Stanford engineers have developed a low-cost, plastic-based textile that, if woven into clothing, could cool your body far more efficiently than is possible with the natural or synthetic fabrics in clothes we wear today. Describing their work in Science, the researchers suggest that this new family of fabrics could become the basis for garments that keep people cool in hot climates without air conditioning.

A 3D printing technique being developed at Stanford could one day allow scientists to study rocks from afar, without needing to have actual samples in hand. By combining two techniques—remote 3D imaging and 3D printing—scientists could create physical models of digitally scanned rocks that are either too delicate to handle or too difficult to obtain in person, such as rocks from the moon or Mars.

Researchers at Stanford and IBM Research report the development of chemical approaches that could efficiently and inexpensively generate biodegradable plastics suitable for making an array of items as diverse as forks, medical devices and fabrics. The study is published in the current issue of Nature Chemistry. As with many chemical reactions, creating biodegradable polyesters requires the assistance of a catalyst – a special class of chemical that increases the rate of a reaction or pushes it over an energetic hurdle.

A paper published in the journal Nature Materials reshapes our understanding of the materials in important protective layers. In the study, Stanford's Reinhold Dauskardt, a professor of materials science and engineering, and doctoral candidate Joseph Burg reveal that those glassy materials respond very differently to compression than they do to the tension of bending and stretching.