Phys.org October 28, 2024 Researchers in Japan synthesized Fe-doped polyaniline (D-PANI) in which they observed diamagnetism at T < 24 K under a weak external magnetic field. D-PANI was air-stable and showed the Peierls transition, as its resistivity increased rapidly at low temperatures, behaving as an electromagnetic insulator. It showed high sensitivity to magnetic fields, with its diamagnetic character changing under a relatively low magnetic field at 4 K. Its resistivity remained almost constant at high temperatures, and the nearest neighbor electron hopping conduction. Polarons in D-PANI showed perfect diamagnetism at low temperatures. After purification, D-PANI contained C, N, O, […]
Tag Archives: Polymers
Composite plastic degrades easily with bacteria, offers environmental benefits
Phys.org September 5, 2024 Researchers in Israel fabricated a biodegradable composite material based on hydroxyethyl cellulose polymer and tyrosine nanocrystals, which demonstrated enhanced strength and ductility superior to most biodegradable plastics. This emergent behavior resulted from an assembly pattern that led to a uniform nanoscale morphology and strong interactions between the components. Water-resistant biodegradable composites encapsulated with hydrophobic polycaprolactone as a protection layer were also fabricated. According to the researchers self-assembly of robust sustainable plastics with emergent properties by using readily available building blocks provides a valuable toolbox for creating sustainable materials… read more. Open Access TECHNICAL ARTICLE
Surprise! Weaker bonds can make polymers stronger
MIT News June 22, 2023 Tough materials can sustain substantial subcritical damage without complete failure of the material, but trying to improve toughness can often lead to the degradation of other mechanical properties. Researchers at Duke University developed cyclobutane-based mechanophore cross-linkers that broke through force-triggered cycloreversion led to networks that were up to nine times as tough as conventional analogs. The response was attributed to a combination of long, strong primary polymer strands and cross-linker scission forces that were approximately fivefold smaller than control cross-linkers at the same timescales. According to the researchers the enhanced toughness comes without the hysteresis […]
Power up: New polymer property could boost accessible solar power
Science Daily June 6, 2022 The function of many biomolecules is directly linked to their chirality. Chiral molecules assemble into chiral structures (like nucleic acids forming DNA), and achiral molecules assemble into achiral structures. Researchers at the University of Illinois have observed structural chirality emerging in achiral conjugated polymers. They combined achiral conjugated polymers with a solvent then added the solution, drop by drop, to a microscope slide. As the solvent molecules evaporated, leaving the polymers behind, the solution became more and more concentrated. Soon, the compressed achiral polymers began self-assembling to form structures. They can be used to design […]
Polymer that folds and unfolds under UV radiation
Phys.com November 30, 2021 An international team of researchers (Japan, Switzerland, UK) built the supramolecular polymer from monomers that formed six-membered rosettes stacked on top of one another to give an infinitely long chain. An intrinsic curvature generated along the stacked rosettes caused the nanofibers to twist up and fold into a helical structure. The folding could be removed by triggering a “light switch”. UV-light irradiation caused the monomer to bend, forming a kink in the molecule, reducing the rotation of the rosette, and unfolding the helical structure. A second switch which works using temperature prevented the entire polymer from […]