Nanowerk April 23, 2024 A team of researchers in the US (MIT, University of Wisconsin–Madison, Case Western University) investigated traditional fabrics as emitters and suppressors of sound. They found that when attached to a single strand of a piezoelectric fiber actuator, silk fabric emits 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 sound suppression using two distinct mechanisms – direct acoustic interference where sound reduced by up to 37 […]
Tag Archives: Smart materials
New conductive, cotton-based fiber developed for smart textiles
Science Daily December 11, 2023 Blending conductive fillers with cellulose is the most common means of fiber production. Incorporating a high content of conductive fillers is necessary to achieve desirable conductivity. However, a high filler load deteriorates the processability and mechanical properties of the fibers. Researchers at Washington State University developed wet-spun cellulose-based fibers with a unique side-by-side (SBS) structure via sustainable processing. They engineered sustainable sources (cotton linter and post-consumer cotton waste) and a biocompatible intrinsically conductive polymer (i.e., polyaniline, PANI) into fibers containing two co-continuous phases arranged side-by-side… read more. TECHNICAL ARTICLE
Smart material prototype challenges Newton’s laws of motion
Nanowerk May 18, 2023 The conventional mechanical metamaterials with inner resonators are characterized as homogenized solids with symmetric effective mass density tensors to interpret subwavelength wave attenuation mechanism. A team of researchers at the University of Missouri has presented a class of active metamaterials described by an odd mass density tensor which is no longer symmetric and whose nonzero asymmetric part arises from active and nonconservative forces. The unconventional wave phenomena caused by the odd mass density were demonstrated experimentally and numerically. The directional wave amplification was also illustrated by controllable feed-forward electric circuits. According to the researchers their findings […]
Novel smart material enables high-performance and reliable light control of droplets
Nanowerk August 24, 2022 Light control of droplets enables remote and contactless control with remarkable spatial and temporal accuracy. However, their performance, and reliability are challenging. Researchers in China have developed a new smart material with photo-induced charge regeneration capability, enabling light control of droplets with superior performance and reliability. The smart material contains three core components: micro-size liquid metal particles with superior photothermal and thermally conductive properties; polyvinylidene fluoride trifluoroethylene copolymer with excellent ferroelectric and mechanical behaviors; and micro-pyramidal structures and low-surface-energy coatings of fluorinated SiO2 nanoparticles for enhancing the superamphiphobicity. The photo-induced charged surfaces (PICSs) possess a superior […]
Novel fluorescent organohydrogel proposed to achieve dual information encryption
Phys.org June 10, 2022 Researchers in China designed an organohydrogel by constructing interpenetrating organohydrogel networks, in which naphthylamide moieties (DEAN, green-yellow emission) are introduced in hydrophilic poly(N,N-dimethylacrylamide) (PDMA) hydrogel network and anthracene units (blue emission) are copolymerized in hydrophobic polystearate methacrylate (PSMA) organogel network. UV light of 365 nm triggers the unimer–dimer transition and leads the fluorescent color of organohydrogel to change from blue to faint yellow. Photomasks store the secret information. They achieved dual encryption by combining crystallization-induced shape memory performance. According to the researchers fluorescent organohydrogel provides a new idea for fabricating smart materials with the ability of […]
DNA circuits
EurekAlert June 2, 2021 Researchers in China have developed a configurable, multi-mode logic switching network that reacts differently with its surroundings depending on pH and DNA input. They developed a series of four DNA switches, each with slightly different lengths and combinations of bases. At a slightly alkaline pH of 8, two of the switches formed triple-stranded DNA, while the others remained loosely stretched out. These reactions and folds led to secondary reactions, which were utilized by the researchers as logic functions in the switching circuit. In demonstration DNA acted as a crosslinker, joining the polymer molecules in the gel […]
Engineers develop ‘chameleon metals’ that change surfaces in response to heat
Phys.org January 13, 2020 Researchers at Iowa State University started with a liquid metal alloy of gallium, indium and tin synthesized into particles covered with a smooth oxide shell that has been chemically stabilized. As the particles are heated, the surface thickens and stiffens and begins to behave more like a solid. Eventually the surface breaks, allowing the liquid metal inside to come to the surface. The most reactive, gallium, breaks through first. More heat brings indium to the surface. And the highest heat—about 1,600 degrees Fahrenheit—brings out florets of tin. Time, temperature and oxygen levels are carefully controlled by […]