Phys.org December 13, 2024 Thermoplastic elastomers (TPEs) are nanostructured, melt-processable, elastomeric block copolymers. When TPEs that form cylindrical or lamellar nanostructures are macroscopically oriented, their material properties can exhibit several orders of magnitude of anisotropy. Researchers at Princeton University demonstrated that the flows applied during the 3D printing of a cylinder-forming TPE enables hierarchical control over material nanostructure and function. 3D printing allowed control over the extent of nanostructural and mechanical anisotropy. They had tunable local and macroscopic mechanical responses. They achieved melt-reprocessability over multiple cycles, reprogramability, and robust self-healing via a brief period of thermal annealing, enabling facile fabrication […]
Category Archives: Advanced materials
Space-time crystals, an important step toward new optical materials
Nanowerk December 8, 2024 Photonic time crystals consist of materials with uniform composition in space, but properties that vary periodically over time which allows the modulation of the spectral composition of light, and amplification as needed. It is on high demand for current, and possibly also future materials platforms because their small modulation strength. An international team of researchers (Germany, Finland) demonstrated that by introducing temporal variations in a resonant material, the momentum bandgap could be drastically expanded with modulation strengths with known low-loss materials and realistic laser pump powers. The resonance could emerge from an intrinsic material resonance or […]
Successful experiment paves the way for discovery of a new element
Phys.org October 22, 2024 An international team of researchers (USA – Lawrence Berkeley National Laboratory, San Jose State University, Oregon State University, Lawrence Livermore National Laboratory, Texas A&M University, UC Berkeley, Oak Ridge National Laboratory, Argonne National Laboratory, Sweden, France, UK, Switzerland) tested a new method for observing the element livermorium, which has 116 protons in its atomic nucleus. The superheavy elements first required an accelerator to deliver an intense ion beam, which was then focused onto a target. The target consisted of a thin layer of an element heavier than uranium. The product formed during the fusion reaction could […]
Scientists develop the next generation of highly efficient memory materials with atom-level control
Phys.org June 27, 2024 Recently a single-phase material concurrently exhibiting magnetism and the spin Hall effect has emerged as a scientifically and technologically interesting platform for realizing efficient and compact spin–orbit torque (SOT) systems. Researchers in South Korea demonstrated external-magnetic-field-free switching of perpendicular magnetization in a single-phase ferromagnetic and spin Hall oxide SrRuO3 by delicately altering the local lattices of the top and bottom surface layers of SrRuO3, while retaining a quasi-homogeneous, single-crystalline nature of the SrRuO3 bulk. This led to unbalanced spin Hall effects between the top and bottom layers. SrRuO3 exhibited the highest SOT efficiency and lowest power […]
Researchers create new class of materials called ‘glassy gels’
Phys.org June 19, 2024 By swelling with solvent, glassy polymers can become gels that are soft and weak yet have enhanced extensibility. The marked changes in properties arise from the solvent increasing free volume between chains while weakening polymer–polymer interactions. A team of researchers in the US (North Carolina State University, University of Nebraska) developed a unique class of materials called glassy gels with desirable properties of both glasses and gels by solvating polar polymers with ionic liquids at appropriate concentrations. The ionic liquid increases free volume and extensibility despite the absence of conventional solvent. It forms strong and abundant […]
New fabric makes urban heat islands more bearable
Science Daily June 13, 2024 Urban areas have heat island effects that largely diminish the effectiveness of cooling textiles as wearable fabrics because they absorb emitted radiation from the ground and nearby buildings. A team of researchers in the US (University of Chicago, Duke University) developed a mid-infrared spectrally selective hierarchical fabric (SSHF) with emissivity greatly dominant in the atmospheric transmission window through molecular design, minimizing the net heat gain from the surroundings. The SSHF featured a high solar spectrum reflectivity of 0.97 owing to strong Mie scattering from the nano-micro hybrid fibrous structure. The SSHF was 2.3°C cooler than […]
This sound-suppressing silk can create quiet spaces
MIT News May 7, 2024 A team of researchers in the US (MIT, University of Wisconsin, Case Western Reserve University, Rhode Island School of Design) investigated traditional fabrics as emitters and suppressors of sound. When attached to a single strand of a piezoelectric fiber actuator, a silk fabric emitted up to 70 dB of sound. Despite the complex fabric structure, vibrometer measurements revealed behavior reminiscent of a classical thin plate. Fabric pore size relative to the viscous boundary layer thickness was found to influence acoustic-emission efficiency. They demonstrated two sound suppression using two distinct mechanisms. In the first, direct acoustic […]
New metasurface innovation unlocks precision control in wireless signals
Nanowerk April 22, 2023 Polarization conversion and beam scanning metasurfaces are commonly used to reduce polarization mismatch and direct electromagnetic waves in a specific direction to improve the strength of a wireless signal. However, identifying suitable active and mechanically reconfigurable metasurfaces for polarization conversion and beam scanning is a considerable challenge, and the reported metasurfaces have narrow scanning ranges, are expensive, and cannot be independently controlled. Researchers in South Korea proposed a reconfigurable transmissive metasurface combined with a scissor and rotation actuator for independently controlling beam scanning and polarization conversion functions. They constructed metasurface with rotatable unit cells (UCs) that […]
Researchers uncover kinky metal alloy that won’t crack at extreme temperatures at the atomic level
Phys.org April 22, 2024 Refractory alloys are very resistant to heat and wear but are not ductile or resistant to fracture. A team of researchers in the US (UC Berkeley, Lawrence Berkeley National Laboratory, UC Irvine, Pacific Northwest National Laboratory) examined the strength and fracture toughness of the Single-phase body-centered cubic (bcc) refractory alloy, NbTaTiHf, from 77 to 1473 kelvin. Whereas the glide and intersection of screw and mixed dislocations promoted strain hardening controlling uniform deformation, the coordinated slip of <111> edge dislocations with {110} and {112} glide planes prolonged nonuniform strain through formation of kink bands. These bands suppressed […]
New adhesive tape picks up and sticks down 2D materials as easily as child’s play
Science Daily February 9, 2024 The use of graphene and other 2D materials to create electronic and optoelectronic devices has been limited by the lack of effective large-area transfer processes. An international team of researchers (South Korea, Japan) has developed a method that uses functional tapes with adhesive forces controlled by ultraviolet light. The adhesion of the tape was optimized for the transfer of monolayer graphene, providing a yield of over 99%. Once detached from the growth substrate, the graphene/tape stack enables easy transfer of graphene to the desired target substrate. The method could be used to transfer other 2D […]