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Highlights

Highlights

Endblock Co-Polymers
Endblock Co-Polymers
Jun 10, 2024
Big Idea: Understanding the Rules of Life

Control of Solution Phase Behavior through Block−Random Copolymer Sequence

L. W. Taylor1, R. D. Priestley1, R. A. Register1 (1Princeton University, USA)
Princeton researchers alter a sequence of random copolymers and provide the first experimental observations of thermoreversible crew-cut micelles, and thermotropic micro- and macrophase separation in a nonaqueous polymer solution.
(A) Pd electrodes (pink) deposited on hBN film (blue) in contact with WTe2 (dashed outline) before heating. (B) Heating leads to formation of an ultrathin layer of Pd7WTe2 (dark blue).
(A) Pd electrodes (pink) deposited on hBN film (blue) in contact with WTe2 (dashed outline) before heating. (B) Heating leads to formation of an ultrathin layer of Pd7WTe2 (dark blue).
Jun 7, 2024
Big Idea: Quantum Leap

Novel 2D chemistry and superconducting quantum engineering
MRSEC researchers from Princeton University have discovered a surprising on-chip process for growing ultrathin superconductors on ultrathin layers of transitionmetal dichalcogenides (TMD).
May 28, 2024
Center for Precision Assembled Quantum Materials (PAQM)

Engineering exceptional transport in van der Waals superatomic semiconductors
The PIs of IRG2 have substantially refined synthetic control over the synthesis of superatoms and their assemblies into macroscopic single crystals. They are now leveraging this control to engineer new, exceptional semiconductor transport properties not seen in any other material.
May 28, 2024
Center for Precision Assembled Quantum Materials (PAQM)

Programming magnetic domains in ferrimagnetic MnSb2Te4
Mn(Bi, Sb)2Te4, a family of MTMs with highly tunable properties, is an ideal playground for studying the interplay of band topology with magnetism. While previous work has focused on uniform ordered phases, here we ask: How can we control the electronic properties of Mn(Bi, Sb)2Te4 using the mesoscale structure of magnetism?
MRSEC graduate student Adriana Santiago-Ruiz explaining the details of a hands-on experiment done during an "Exploring Evolving Nanotechnologies" workshop at Experimenta con PREM.
MRSEC graduate student Adriana Santiago-Ruiz explaining the details of a hands-on experiment done during an "Exploring Evolving Nanotechnologies" workshop at Experimenta con PREM.
May 22, 2024
UPENN Materials Research Science and Engineering Centers

Experimenta con PREM

Mark Licurse & Ashley Wallace, University of Pennsylvania
Experimenta con PREM is a two-week hands-on research program for high school students run annually at the University of Puerto Rico (UPR) Humacao & Cayey campuses. It remains a core program for the UPR-Penn PREM program with a history of attracting talented and motivated high school students to materials research; since its inception in 2005, 100% of students have graduated from high school and 78% pursue STEM after.
A graphic showing the sunlight reflecting on a 'wet' surface and transmitting on a 'dry' surface above and image of a white beetle.
A graphic showing the sunlight reflecting on a 'wet' surface and transmitting on a 'dry' surface above and image of a white beetle.
May 22, 2024
UPENN Materials Research Science and Engineering Centers

Beetle Scales Inspire a Passive Daytime Radiative Cooling Coating

Kathleen Stebe and Daeyeon Lee, University of Pennsylvania
Passive daytime radiative cooling (PDRC) coatings provide an eco-friendly and cost-effective alternative to cool surfaces and structures. Ideally, these coatings would have excellent cooling performance in thin, mechanically robust layers that could switch from rejecting heat to accepting heat during periods of low sunlight and would be produced by low-cost and scalable methods.  
Simulations showing how the height (t), length (lx) and spacing (sx) alter the stress (VM) at a crack tip and thereby prevent crack propagation and increase toughness
Simulations showing how the height (t), length (lx) and spacing (sx) alter the stress (VM) at a crack tip and thereby prevent crack propagation and increase toughness
May 22, 2024
UPENN Materials Research Science and Engineering Centers

Architecting Crack Tips to Enhance Fracture Toughness

Kevin Turner (University of Pennsylvania), Michal Budzic (Aarhus, Denmark)
One of the primary ways that materials fail in operation is by the formation and propagation of cracks during loading, often leading to sudden, catastrophic events. The ability of a material to withstand fracture is described as its toughness.  Over the years, researchers have developed a variety of way to enhance material toughness, thereby improving the ability of materials to withstand applied loads, but often at the cost of reducing overall strength.
Polarized Optical Microscopy (POM) images of three nematic liquid crystal droplets (16.6, 19.9, and 26.7 μm in radius) reveal a configuration transition at a critical magnetic field. Before the transition, droplets exhibit a deformed radial state with a point defect. After the transition, droplets adopt an axial-with-defect state, featuring a ring defect. The transition is highlighted in a magnified red circle region. Simplified schematics illustrate the defect structures before and after the transition. The magnetic field strength for each frame and the orientation of the polarizer and analyzer are indicated in the images. The text in the bottom of each image indicates the field strength in Tesla.
Polarized Optical Microscopy (POM) images of three nematic liquid crystal droplets (16.6, 19.9, and 26.7 μm in radius) reveal a configuration transition at a critical magnetic field. Before the transition, droplets exhibit a deformed radial state with a point defect. After the transition, droplets adopt an axial-with-defect state, featuring a ring defect. The transition is highlighted in a magnified red circle region. Simplified schematics illustrate the defect structures before and after the transition. The magnetic field strength for each frame and the orientation of the polarizer and analyzer are indicated in the images. The text in the bottom of each image indicates the field strength in Tesla.
May 21, 2024
UPENN Materials Research Science and Engineering Centers

New Configuration Transitions of Nematic Liquid Crystals in Drops Induced by Magnetic Fields

Arjun Yodh, James Kikkawa, University of Pennsylvania, Peter Collings, Swarthmore College
IRG-3 researchers Yodh, Kikkawa and Collings made a significant discovery about the behavior of liquid crystals (LCs) in droplets exposed to a magnetic field. LCs are unique materials that flow like liquids but also have some order (orientational order) like crystals. In this study, the researchers focused on a specific type of LC phase called a nematic. Field-induced “switching” of nematic liquid crystals (NLCs) in planar geometries is the basis of LC displays. Here, NLCs were put in spherical drops with special molecules (surfactants) on the drop surface that align the molecules, or NLC director, perpendicular to the droplet surface and force a topological hedgehog defect to form at the drop center. Field-induced switching in this case differs fundamentally from the planar cells due to confinement geometry and the topological defect.
(left) Polarized optical microscopy images showing that the ligands can align nanocrystal assembly, (middle) illustration of the proposed ligand arrangement, (right) Dendritic Promesogenic Ligands used in the study
(left) Polarized optical microscopy images showing that the ligands can align nanocrystal assembly, (middle) illustration of the proposed ligand arrangement, (right) Dendritic Promesogenic Ligands used in the study
May 21, 2024
UPENN Materials Research Science and Engineering Centers

Controlling Nanoparticle Assemblies with Dendritic Ligands

Christopher Murray and Chinedum Osuji, University of Pennsylvania
Liquid crystals are soft materials which see frequent use in optical displays and other smart devices. This is because they can change their optical properties (such as light transmission and polarization) when an electric field is applied. This allows them to selectively block or transmit light, creating the pixels that form images on the screen. Similarly, nanoparticles are materials that can have different optical properties that depend on their size. In this work, Penn researchers have developed new liquid crystal-nanoparticle hybrid systems. They have integrated specially synthesized molecules known as “dendritic promesogenic ligands” that can attach to the nanoparticles.  
Shear bands formation in different disordered solids are well-captured by our mesoscopic StEP model. From left to right: simulated atomic glasses (left), experimental granular packing (middle), and a simulated polymer glass (right). The particles are colored according to their local strain with darker red indicating higher strain, and the applied strain localizes in all three cases. The bottom row has the stress/strain response of the three systems measured in simulations or experiments compared to the StEP model for the same three systems, showing very good agreement.
Shear bands formation in different disordered solids are well-captured by our mesoscopic StEP model. From left to right: simulated atomic glasses (left), experimental granular packing (middle), and a simulated polymer glass (right). The particles are colored according to their local strain with darker red indicating higher strain, and the applied strain localizes in all three cases. The bottom row has the stress/strain response of the three systems measured in simulations or experiments compared to the StEP model for the same three systems, showing very good agreement.
May 21, 2024
UPENN Materials Research Science and Engineering Centers

Understanding Deformation in Disordered Materials

Robert Riggleman, Douglas Durian and Andrea Liu, University of Pennsylvania
Disordered particulate solids are ubiquitous in items ranging from plastic to concrete. Despite their prevalence, applications can be limited because they are often brittle. In contrast, ductile materials can be deformed smoothly and significantly without fracturing. Strategies for tuning ductility of disordered solids are empirical and system-specific.  Liu, Riggleman and Durian used computer simulations of atomic and polymeric glasses and laboratory experiments on granular packings to develop a general Structuro-Elasto-Plastic (StEP) framework for understanding large-scale deformation of disordered solids in terms of the system-specific interplay between local structure, local rearrangements and larger-scale elasticity.  

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