Phys.org November 29, 2022 DNA conformation is well understood for biological processes. An international team of researchers (Austria, Poland, Italy) focused on chains interlocking the rings and observed their behavior and how they could be used to design innovative materials. They showed that circular polycatenanes have physical and geometrical properties very similar to those of double stranded DNA rings. They demonstrated that the connection of local and global properties holds for these structures too, that is there is a connection between what occurs in a part of the structure and in its whole. The amount of twist of the polycatenanes […]
Category Archives: Adaptive materials
Scientists engineer new material that can absorb and release enormous amounts of energy
Phys.org February 2, 2022 Solid–solid phase transformations can affect energy transduction and change material properties. A team of researchers at UMass Amherst developed elasto-magnetic metamaterials that display phase transformation behaviors due to nonlinear interactions between internal elastic structures and embedded, macroscale magnetic domains. They also developed the design algorithms that allow these materials to be programmed with specific responses, making them predictable. Using predictive model, they developed a quantitative phase map that relates the geometry and magnetic interactions to the phase transformation. According to the researchers their work demonstrates that the new material holds great promise for a very wide […]
Creating an artificial material that can sense, adapt to its environment
Phys.org November 2, 2021 A team of researchers in the US (University of Missouri, University of Chicago) has developed an artificial material that uses a computer chip to control or manipulate the processing of information that’s needed to perform the requested actions, then uses the electrical power to convert that energy into mechanical energy. The material incorporates three main functions also displayed by materials found in nature—sensing; information processing; and actuation, or movement. They control how the material responds to changes in external stimuli found in its surroundings. According to the researchers their approach, built on symmetries and conservation laws, […]
Stronger than spider silk: Bagworm silk enables strong conducting fibers
Science Daily October 22, 2021 Researchers in Japan combined polyaniline, a conducting polymer that can be easily synthesized, with bagworm silk obtained from a bagworm nest. The composite fibers obtained from the silk and polyaniline were 2 microns in diameter and acted as optical waveguides. They demonstrated that green laser light propagates along these fibers, while remaining confined within each fiber. Using SQUID measurements they determined that the fibers can act as paramagnets. By applying the bagworm silk/polyaniline composite in a field-effect transistor device, the research team also confirmed that the composite fiber is suitable for use in textile transistors. […]
Physicists engineer new property out of ‘white’ graphene
Nanowerk September 7, 2021 An international team of researchers (USA – MIT, Japan) has demonstrated that when two single sheets of boron nitride are stacked parallel to each other, at room temperature, the material becomes ferroelectric, in which positive and negative charges in the material spontaneously head to different sides, or poles. Upon the application of an external electric field, those charges switch sides, reversing the polarization. Twisting the boron nitride sheets by a small angle changes the dynamics of switching because of the formation of moiré ferroelectricity with staggered polarization. The coupling between vertical polarization and horizontal motion is […]
Water-repellent nanomaterial inspired by nature
Science Daily September 7, 2021 Using colloidal gels of fullerite C60 and C70 nanocrystals researchers at the University of Central Florida have developed superhydrophobic films and coatings. They demonstrated that despite the high surface energy of these van der Waals molecular crystals their gelation can create films having self-affine fractal surfaces with multiscale roughness. In experiments when submerged in water the material stayed dry up to 3 h even at a water depth of two feet and exhibit the plastron effect. According to the researchers non-wettable films of such materials are unique as fullerites get photosensitized instantaneously generating extremely high […]
New form of carbon in a mesh tantalizes with prospects for electronics
Nanowerk August 27, 2021 Biphenylene network is highly conductive and may prove able to store more electrical energy than even graphene. However, their syntheses remain challenging given the lack of reliable protocols for generating nonhexagonal rings during the in-plane tiling of carbon atoms. An international team of researchers (Germany, Finland, Japan) has grown an ultraflat biphenylene network with periodically arranged four-, six-, and eight-membered rings of sp2-hybridized carbon atoms through an on-surface interpolymer dehydrofluorination (HF-zipping) reaction. The characterization of this biphenylene network by scanning probe methods reveals that it is metallic rather than a dielectric. They expect the interpolymer HF-zipping […]
Scientists develop chain mail fabric that can stiffen on demand
Science Daily August 12, 2021 Structured fabrics, such as woven sheets or chain mail armours, design can target desirable characteristics, such as high impact resistance, thermal regulation, or electrical conductivity. However, the properties are usually fixed. An international team of researchers (Singapore, USA – Caltech) has developed new chain fabric that is flexible like cloth but can stiffen on demand. It comprises hollow octahedrons that interlock with each other. Increase in bending resistance arises because the interlocking particles have high tensile resistance. They found that chain mails, consisting of different non-convex granular particles, undergo a jamming phase transition that is […]
Autonomous self-healing seen in piezoelectric molecular crystals
Phys.org July 23, 2021 Self-healing polymers, gels and other materials developed so far have been soft. To develop self-healing hard materials, an international team of researchers (India, Germany) grew bipyrazole organic crystals in tiny (2mm long by 0.2mm wide) needle shapes. When pressure was applied they broke but and then bounced back from the break into straight-line needles again, verifying that the material had truly healed. It is not clear if the type of crystals produced the team will be useful in any given product. However, the work shows that piezoelectric molecular crystals can be grown in ways that allow […]
Dancing with the light: A new way to make crystals bend by shining light
Nanowerk July 30, 2021 Only very thin crystals (up to 20 microns) can show appreciable mechanical response. Researchers in Japan accidentally discovered that the photothermal effect causes a crystal to bend fast. To create a new, faster bending crystal and clarify the underlying mechanism, they exposed a thin salicylideneaniline derivative crystal to UV light and obtained substantial bending within approximately 1 second. However, the bend angle dropped rapidly with increasing crystal thickness, revealing that the bending was caused by photoisomerization. When they illuminated a thick (>40 microns) crystal with UV light, they observed an extremely rapid bending within several milliseconds, […]