Welcome to the Greer Group

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The key focus of the Greer group is on creating and studying advanced materials that utilize combination of 3-dimensional hierarchical architectures and nanoscale material size effects . Creation of extremely strong yet ultra-light materials can be achieved by capitalizing on the hi­e­r­a­­r­chical design of 3-dimensional nano-architectures. Such structural meta-materials exhibit superior thermo­mechanical pro­­­per­­ties at ex­tre­me­ly low mass densities (lighter than aerogels), making these solid foams ideal for many scientific and tech­no­lo­gi­cal applications. The dominant de­for­mation mechanisms in such “meta-materials”, where individual constituent size (nanometers to microns) is compa­rable to the characteristic microstructural length scale of the constituent solid, are essentially un­known. To harness the lucrative properties of 3-dimensional hierarchical nanostructures, it is critical to assess mechanical properties at each relevant scale while capturing the over­all structural complexity.

Fractal nanotruss made by Nigel and Lucas

We fabricate 3-dimensional nano-lattices whose constituents vary in materials (ceramics, metals, metallic glasses, semiconductors, etc.) and in size from several nanometers to tens of microns to millimeters. We study the deformation and mechanical properties of a range of nano-sized solids with different microstructures by using in-situ nano mechanical experiments and atomistic simulations. We focus on investigating the interplay between the internal critical microstructural length scale of materials and their external limitations in revealing the physical mecha­nisms which govern the mechanical deformation, where competing material- and structure-induced size effects drive overall properties.

We focus on the deformation and failure in metallic, ceramic, and glassy nano structures and discuss size effects in nanomaterials in the framework of mechanics and physics of defects. Specific examples include: fabrication and characterization of hierarchical 3-dimensional architected meta-materials for applications in biomedical devices, ultra lightweight batteries, and damage-tolerant cellular solids, nano-mechanical experiments, flaw sensitivity in fracture of nano structures.

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Group News
June. 201: Daryl was selected into the Biotechnology Leadership Predoctoral Program in Micro/Nanomedicine at Caltech that will provide him the opportunity to work at biotech companies via internships! Congratulations, Daryl!
June. 201: Congratulations to Bryce for being the first of his class to pass his candidacy exam!
June. 201: Ryan was recently awarded with a CCE Teaching Assistantship Award granted to the division's most exceptional teaching assistants. Congratulations!
Apr. 2017: The Greer troops present at the MRS Spring 2017 meeting! Adenike, Xiaoxing, and Xuan present talks, and Julia presents in Symposium X. Click here to see a video/write-up of her talk.
Dec. 2016: Chen's new paper in PNAS on properties of small-scale Li is featured on the front page of Caltech news today! See it here!
Dec. 2016: Congratulations to Diandra Almasco (and her mentor Carlos Portela) for winning first place for her SURF poster!
Sep. 2016: Congratulations to Amanda for passing her qualifying exams!
Sep. 2016: Congratulations to Dr. Rachel Liontas on completing her PhD!
Aug. 2016: Congratulations to our newest PhD - Dr. Chen Xu on a successful defense!
May 2016 : Congratulations to Ryan, Max, Mike, Arturo, Carlos, Daryl, Alessandro, and Adenike for passing their candidacy exams!
May 2016 : Congratulations to the now Dr. Lucas Meza and Dr. David Chen on successfully defending both of their dissertations!
Mar. 2016: Check out Julia's new video on CNN!
Mar. 2016: Julia was named as one of fifteen 2016 National Security Science and Engineering Faculty Fellows by the DoD! See it here.
Feb. 2016: Zach and Eric's new PNAS paper is featured in a Caltech news article!
Jan. 2016: See the new NBC-NSF video featuring the Greer group that went live today!
Dec. 2015: Greer troops take MRS by storm, with presentations by David Chen, Viki Chernow, Lauren Montemayor (alum), Julia, and posters by Dylan and Adenike. Adenike also gave a talk at the African MRS after.
Dec. 2015: Special issue of MRS Bulletin with a focus on Innovation comes out, with a featured review article by Viki and Lauren!
Nov. 2015: Julia gives a talk at TEDxManhattanBeach. See the talk here.
Oct. 2015: Congratulations to Dylan for his wonderful talk at the 2015 ECS fall conference and to Xiaoxing for winning the best poster award!
Sep. 2015: Congratulations to Carlos for passing his Qualifying Exams!