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Highlights

Highlights

Apr 6, 2022
Big Idea: Future of Work at the Human-Technology Frontier

Leaders in Innovation: New Startups Addressing Societal Problems
The Harvard MRSEC provides a vibrant culture of entrepreneurship and several recent Ph.D. students supported by Center IRGs and seed projects have co-founded new companies. 
(A) Design principle to achieve diverse deformation trajectories: misalignment of molecular anisotropy (M), microstructure geometry (G), and light (L). (B) Formation of a transient propagating bimorph in a single material by directional light-activation with a stationary light source. (C) Upon irradiation from opposite sides, the same microstructure displays mirrored right- and left-handed curved stroke-like trajectories, which are captured by FE modeling. (D) Spontaneous self-organization of strings of microposts into an undulating line. Modeling results on the right. (E) Simulation and experimental results of X-shaped jointed compositionally uniform microactuators exhibit twisting/rotation of the stem and amplified sway motion of the horizontal arms.
(A) Design principle to achieve diverse deformation trajectories: misalignment of molecular anisotropy (M), microstructure geometry (G), and light (L). (B) Formation of a transient propagating bimorph in a single material by directional light-activation with a stationary light source. (C) Upon irradiation from opposite sides, the same microstructure displays mirrored right- and left-handed curved stroke-like trajectories, which are captured by FE modeling. (D) Spontaneous self-organization of strings of microposts into an undulating line. Modeling results on the right. (E) Simulation and experimental results of X-shaped jointed compositionally uniform microactuators exhibit twisting/rotation of the stem and amplified sway motion of the horizontal arms.
Apr 6, 2022
Big Idea: Future of Work at the Human-Technology Frontier

Self-Regulated Non-Reciprocal Motions in Liquid Crystal Elastomer Pillars

A team at the Harvard MRSEC led by Bertoldi and Aizenberg has developed an approach to achieve a diverse trajectories from a single-material system via self-regulation: when a photoresponsive liquid crystal elastomeric pillar with mesogen alignment is exposed to light, it ‘dances’ dynamically as light initiates a traveling order-to-disorder transition front that twists and bends via opto-chemo-mechanical feedback.
Dec 23, 2021
Center for Hybrid, Active, and Responsive Materials

MRSEC collaborations celebrate diversity and professional growth in materials research

K. Bothi, T. Epps, III, L. Korley University of Delaware MRSEC DMR-2011824
UD CHARM and Princeton’s PCCM coordinated with the Chicago MRSEC to host three virtual events (Soft Matter for All, Rising Stars, and a Professional Development Workshop) to highlight early career, high-impact research and ignite discussion for graduate students and postdocs pursuing academic and non-academic career paths.
Dec 23, 2021
Center for Hybrid, Active, and Responsive Materials

Spin-to-charge conversion in ferromagnet/ topological insulator bilayers at GHz and THz frequencies

B. Jungfleisch, L. Gundlach, A. Janotti (University of Delaware) and G. Bryant (NIST) University of Delaware MRSEC DMR-2011824
Experimental studies combined with theoretical calculations of spin dynamics across a wide frequency range from ~10 GHz to several THz in a novel amorphous ferromagnet (FM)/3D topological insulator (TI) (FeGaB/BiSb) system that is scalable and provides a promising platform for spin-electronic devices.
Nov 29, 2021
The Bioinspired Soft Materials Center

Deformation and Orientational Order of Chiral membranes with Free Edges

L. Ding,  R. A. Pelcovits,  T. R. Powers: Brown University Z. Dogic: Brandeis University, UCSB  
Producing self-assembled structures of prescribed limited size and shape is a major challenge in nanoscience. A major achievement of the MRSEC was to elucidate a new chirality-based mechanism that leads to self-limiting assembly of colloidal rafts.
Nov 29, 2021
The Bioinspired Soft Materials Center

Confinement Controls the Bend Instability of Three-Dimensional Active Liquid Crystals

G. Duclos, A. Baskaran: Brandeis University Z. Dogic: Brandeis University, UCSB
Here, three IRG2 PP developed a combination of experiments with 3D active fluids confined in microfluidic channels and a minimal hydrodynamic model to show that size of the channel determines the emergent lengthscale of the growing deformations. These findings will advance our understanding of active nemato-hydrodynamics and the pathways to 3D active turbulence at low Reynolds number.
During fibrosis, collagen fibers become denser and aligned. Engineered fibrous matrices now respond to mechanical loading to densify and align fibers through inter-fiber adhesion.
During fibrosis, collagen fibers become denser and aligned. Engineered fibrous matrices now respond to mechanical loading to densify and align fibers through inter-fiber adhesion.
Aug 3, 2021
UPENN Materials Research Science and Engineering Centers

Fibrous Networks in Liver Fibrosis

Rebecca Wells, Jason Burdick, Vivek Shenoy, University of Pennsylvania
Animal  tissues are composed of cells attached to either the surface of a fibrous network called a basement membrane or embedded within a 3D extracellular or interstitial matrix. As the disease liver fibrosis progresses, the extracellular fibrous networks become denser and more aligned. These physical changes lead to different mechanical properties and structures to which cells are exquisitely sensitive. To better understand the pathological effects of these changes during fibrosis on cells, we have engineered material platforms that mimic the extracellular matrix in tissue health and disease. As an example, we have fabricated fibrous materials that have varied mechanical properties and fiber densities when mechanically loaded due to the chemical adhesion between fibers, similar to natural extracellular matrix (see Figure).
The molecular clutch model (top) of mechanotransduction explains the effect of matrix viscoelasticity on cell spreading. Simulations predict optimal cell spreading when the timescale for stress relaxation (τs) is similar to the clutch binding timescale (τb).
The molecular clutch model (top) of mechanotransduction explains the effect of matrix viscoelasticity on cell spreading. Simulations predict optimal cell spreading when the timescale for stress relaxation (τs) is similar to the clutch binding timescale (τb).
Aug 3, 2021
UPENN Materials Research Science and Engineering Centers

Effects of extracellular matrix viscoelasticity on cellular behavior

Paul Janmey, Vivek Shenoy, University of Pennsylvania
Linearly elastic elastomers coated with matrix proteins are widely used to assess the role of stiffness. Such experiments are often assumed to reproduce the effect of the mechanical environment experienced by cells in vivo. However, tissues and the extracellular matrix (ECM) are not linearly elastic materials. They exhibit far more complex mechanical behaviors. These behaviors include viscoelasticity, as well as mechanical plasticity, and nonlinear elasticity. Our theoretical and experimental work has revealed that matrix viscoelasticity regulates fundamental cell processes and can promote behaviors – such as proliferation, motility and spreading – that are not observed with elastic hydrogels in both two- and three-dimensional culture microenvironments.
(Top) Experimental setup (left) and map of creep strains within the sandpile measured via Diffusive Wave Spectroscopy (DWS) (right). At the moment of preparation and up to 11 days after pouring (right), spatially-heterogeneous creeping motions appear within the pile. (Bottom) Heat perturbations reset the creep rate and the timescale of relaxation (left) while tapping reduces the creep rate, and confines deformation to the free surface (right)
(Top) Experimental setup (left) and map of creep strains within the sandpile measured via Diffusive Wave Spectroscopy (DWS) (right). At the moment of preparation and up to 11 days after pouring (right), spatially-heterogeneous creeping motions appear within the pile. (Bottom) Heat perturbations reset the creep rate and the timescale of relaxation (left) while tapping reduces the creep rate, and confines deformation to the free surface (right)
Aug 3, 2021
UPENN Materials Research Science and Engineering Centers

The Perpetual Fragility of Creeping Hillslopes

Douglas J. Jerolmack, Paulo E. Arratia, & Robert A. Riggleman, University of Pennsylvania
Soil is a highly disordered granular material. Slow soil deformation (creep) controls the shape of hills in the natural landscape, and is a precursor of catastrophic landsliding. Our work demonstrates a surprising observation: an apparently static sandpile, sitting on a table, is actually alive with motion. We study a 3D granular heap, confined by walls and prepared by pouring. Via Diffusive Wave Spectroscopy (DWS), we observe the existence of spatially-heterogeneous micro-deformations that decay in size and frequency as time progresses but persist up to 11 days after the preparation of the system; the heap relaxes. We find that this relaxation can be enhanced  (overaged) or reversed (rejuvenated) by tuning the types of disturbances applied to system.
Jun 3, 2021
Big Idea: Quantum Leap

Surface Modification of Black Phosphorus with Group 13 Lewis Acids for Ambient Protection and Electronic Tuning

Alexandra Velian and Mo Li Molecular Engineering Materials Center (MEM-C) University of Washington, Seattle
We have developed a solution-phase protocol to modify the Lewis basic surface of few-layer black phosphorus (bP) using commercially available Lewis acids, and demonstrated its effectiveness at providing outstanding ambient stability and tuning of electronic properties.

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