Highlights
Highlights of IRG research are reported on an ongoing basis to the NSF MRSEC program. Publications supported by Brandeis MRSEC funding are recorded here.
2023
Phase diagram of trumpets. Symbols indicate phases: self-limited (circle), cracked (square),and runaway (red ‘x’). For the self-limited phase, symbols are colored and sized according to the optimal size n*. The gray dashed line is the result of a scaling argument.
Triangular monomers with positive curvature in one direction and negative curvature in another assemble into trumpet shaped objects predicted to have precise self-limited lengths due to frustration-induced stress. However, the continuum theory does not account for potential mechanisms by which the system could “escape” frustration. Computer simulations revealed two escape routes; runaway, in which trumpets flatten and cracked, in which trumpets escape frustration by forming Triangular monomers with positive curvature in one direction and negative curvature in another assemble into trumpet shaped objects predicted to have precise self-limited lengths due to frustration-induced stress. However, the continuum theory does not account for potential mechanisms by which the system could “escape” frustration. Computer simulations revealed two escape routes; runaway, in which trumpets flatten and cracked, in which trumpets escape frustration by forming defects that locally release elastic strain.
Optical control of 2D active nematics – (i) (Left) Schematic of experimental set up. (Right) Snapshot of Local light activation bench mark experiment. (ii) Numerical solution of hydrodynamics with local activation in the form of a stripe (left) and a circle (right).
Biological cells control spatial and temporal generation of active stresses to achieve diverse sought-after functionalities ranging from motility to cell division. Motivated by these observations, IRG2’s goals are to control of spatiotemporal patterns of active stresses and to endow soft materials with lifelike functionalities. Achieving these goals requires development of new elements of active stress that are under external control as well as developing theoretical models that can predict how these stresses are controlled in space and time to generate targeted dynamics.
Top: Schematic of the active elastomer composed of Fascin-bundled actin with intercalating microtubule bundles. Bottom: Visual representation of the system-sized elastic shear waves that emerge in this material.
Active composites obtained by merging a conventional soft matteractin gel with energy consuming microtubule bundles that generate active stresses leads to emergent properties not present in the individual systems. Here, the system exhibits coherent large scale self-driven oscillations, which neither the actin gel nor microtubule bundles will do on their own. The Center will exploit this phenomena to build autonomous soft robots with lifelike attributes.
The goal of the annual Spanish-Language Waltham High School Field Trip is to introduce high school hands-on chemistry experiments facilitated by chemistry graduate and undergraduate students and translated by native Spanish-speakers at Brandeis. Zare worked with WHS teachers to ensure that the experiments aligned with the class curriculum.
The field trip also included small group conversations discussions focused on the Brandeis students’ journey to science and what day-to-day life in research consists of with Brandeis scientists that are fluent in Spanish, an Admissions info session, and lab tours. This field trip engages a cohort at WHS that is not typically targeted for field trips. The inaugural field trip occurred in Summer 2022 and has been repeated in Spring 2023.
Every year, the Brandeis MRSEC aims to hold an IRG Workshop which is a trainee-organized, all-day event for all MRSEC members to gain hands-on experience with the Center’s interdisciplinary research groups.
In Jan 2023, an IRG2 workshop focused on Active Matter where a group of IRG2 trainees worked together to organize a day of computational and experimental training and collaboration. The day consisted of a variety of talks on active matter, theoretical activities, and experimental activities which allowed the Center as a whole to learn more about IRG2. Zare worked closely with trainees to ensure the topics covered and activities included in the workshop were appropriate for a general science audience and encouraged all MRSEC members, regardless of background, to participate. The result of this workshop is increased synergy across the IRGs and community building.
