News & Events

09-20-23

Late last year, Caltech researchers revealed that they had developed a new fabrication technique for printing microsized metal parts containing features about as thick as three or four sheets of paper. Now, the team has reinvented the technique to allow for printing objects a thousand times smaller: 150 nanometers, which is comparable to the size of a flu virus. In doing so, the team also discovered that the atomic arrangements within these objects are disordered, which would, at large scale, make these materials unusable because they would be considered weak and "low quality." In the case of nanosized metal objects, however, this atomic-level mess has the opposite effect: these parts can be three-to-five-times stronger than similarly sized structures with more orderly atomic arrangements.

The work was conducted in the lab of Julia R. Greer, the Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; and Fletcher Jones Foundation Director of the Kavli Nanoscience Institute. It is described in a paper appearing in the journal Nano Letters. [Caltech story]

Tags: APhMS research highlights MCE Julia Greer Wenxin Zhang

06-02-23

The Demetriades - Tsafka - Kokkalis Prizes are awarded annually to PhD candidates selected for the best thesis, publication, or discovery in select fields. Saransh Sharma, advised by Professor Azita Emami, has received the prize in Biotechnology or Related Fields for his research in developing ultra-low power and highly miniaturized medical electronics for in-vivo localization and tracking. Nathaniel Wei, advised by Professor John Dabiri, has received the prize in Environmentally Benign Renewable Energy Sources or Related Fields for his research that explores the ways in which unsteady flows in the atmosphere can be leveraged in wind-energy systems for enhanced performance, robustness, and operational longevity. Rebecca Gallivan, advised by Professor Julia Greer, has received the prize in Nanotechnology or Related Fields. Coupled with the development of novel materials processing, Gallivan's research focuses on uncovering fundamental insight into the relationship between length-scale and microstructural features on nanomechanical phenomena in order to lay the foundation for advanced engineering and complex design of materials in nanotechnologies.

Tags: APhMS EE honors GALCIT MedE MCE John Dabiri Julia Greer Demetriades - Tsafka - Kokkalis Prizes Azita Emami Rebecca Gallivan Saransh Sharma Nathan Wei

12-01-22

Engineers at Caltech have developed a method for 3-D printing pure and multicomponent metals, at a resolution that is, in some cases, an order of magnitude smaller than previously possible. "We had to develop a new way of doing it, and we couldn't rely on heat to build our structures," says Max Saccone. [Caltech story]

Tags: APhMS research highlights MedE MCE MCE Julia Greer Max Saccone Rebecca Gallivan Daryl Yee Kai Narita

07-27-22

For the past two decades, Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, has been at the forefront of creating new materials whose structures are designed and controlled at the smallest level, giving them unusual and useful properties. [Caltech story]

Tags: APhMS MedE MCE Julia Greer alumni Carlos M. Portela

04-26-22

As part of the Science Journeys lecture series—designed to inspire scientific curiosity, especially among students in eighth grade and higher—graduate student Fernando Villafuerte discussed his path to Caltech and his research on batteries, including their role in sustainability solutions. Villafuerte works in the lab of Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; and Fletcher Jones Foundation Director of the Kavli Nanoscience Institute. His research focuses on a novel material known as a solid polymer electrolyte, which could potentially be used to create batteries that can store more energy than currently possible. [Caltech story]

Tags: APhMS research highlights MedE MCE Julia Greer Fernando Villafuerte

04-25-22

Adaptive electric vehicle chargers and advanced battery designs are some of the ways Caltech researchers are building a more sustainable electric grid. Steven Low, Frank J. Gilloon Professor of Computing and Mathematical Sciences and Electrical Engineering, invented the Adaptive Charging Network (ACN). But Low and others warn that this grid is unprepared for the challenges of the 21st century. “The current grid will very soon hit a wall where, when we add renewable energy, it sits unused because the demand isn’t there at a time when the solar is running,” says Adam Wierman, Professor of Computing and Mathematical Sciences; Director, Information Science and Technology. That is why Caltech researchers are working on ways to break down that barrier to help empower an energy transformation. Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, is pushing the limits of the batteries themselves.  [Caltech story]

Tags: EE research highlights CMS Julia Greer Adam Wierman Steven Low Kimberly See

02-01-22

A newly created nano-architected material exhibits a property that previously was just theoretically possible: it can refract light backward, regardless of the angle at which the light strikes the material. "Negative refraction is crucial to the future of nanophotonics, which seeks to understand and manipulate the behavior of light when it interacts with materials or solid structures at the smallest possible scales," says Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute. [Caltech story]

Tags: APhMS research highlights MedE MCE Harry Atwater Julia Greer Victoria Chernow Siying Peng Ryan Ng

06-25-21

Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, has developed a nano-architected material made from tiny carbon struts that is, pound for pound, more effective at stopping a projectile than Kevlar, a material commonly used in personal protective gear. "The knowledge from this work could provide design principles for ultra-lightweight impact resistant materials for use in efficient armor materials, protective coatings, and blast-resistant shields desirable in defense and space applications," says Greer. [Caltech story]

Tags: APhMS research highlights MedE MCE Julia Greer KNI

08-06-20

The energy density of batteries have been a major challenge for consumer electronics, electric vehicles, and renewable energy sources. Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, has made a discovery that could lead to lithium-ion batteries that are both safer and more powerful. Findings provide guidance for how lithium-ion batteries, one of the most common kinds of rechargeable batteries, can safely hold up to 50 percent more energy. "Every power-requiring application would benefit from batteries with lithium instead of graphite anodes because they can power so much more," says Greer. "Lithium is lightweight, it doesn't occupy much space, and it's tremendously energy dense." [Caltech story]

Tags: APhMS research highlights MCE Julia Greer KNI

03-03-20

A new process developed at Caltech makes it possible for the first time to manufacture large quantities of materials whose structure is designed at a nanometer scale—the size of DNA's double helix. Pioneered by Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, "nanoarchitected materials" exhibit unusual, often surprising properties—for example, exceptionally lightweight ceramics that spring back to their original shape, like a sponge, after being compressed. Now, a team of engineers at Caltech and ETH Zurich have developed a material that is designed at the nanoscale but assembles itself—with no need for the precision laser assembly. "We couldn't 3-D print this much nanoarchitected material even in a month; instead we're able to grow it in a matter of hours," says Carlos M. Portela, Postdoctoral Scholar. "It is exciting to see our computationally designed optimal nanoscale architectures being realized experimentally in the lab," says Dennis M. Kochmann, Visiting Associate. [Caltech story]

Tags: APhMS research highlights GALCIT MedE MCE Julia Greer KNI Dennis Kochmann postdocs Carlos Portela