Investigating the influence of conduit residues on polyurethane plates

J. Polym. Sci. Part A: Polym. Chem.

et al. 2018

Toward the goal of smart sensor systems for wearable electronics, polymer microfiber-based free-standing sensors benefit from excellent flexibility, decent ductility, and easy wearability in comparison with thin-film-based sensing devices. Herein, we report a hydrophobic and conducting single-strand microfiber-based liquid-phase chemical sensor consisting of polyurethane (PU), tin oxide (SnO 2 ), and carbon nanotube (CNT) composites with applying a (1H,1H,2H,2H-heptadecafluorodec-1-yl) phosphonic acid (HDF-PA)-based self-assembled monolayer. The free-standing HDF-PA-treated PU-SnO 2 -CNT composite microfiber showing selective filtering properties with the repellency of water and the penetration of an organic solvent is electrically and mechanically characterized. Finally, the singlestrand HDF-PA-treated PU-SnO 2 -CNT composite microfiberbased chemical sensor, which shows excellent mechanical properties and aqueous stability, is demonstrated to detect the presence of a chemical in pure water or counterfeit gasoline in pure gasoline by observing mechanical changes, especially variations in the length and diameter of the fiber, and monitoring the electrical resistance change.In recent years, various chemical sensors using a CNT-polymer composite microfiber have been under study. A gas-phase chemical sensor detects electrical sensing characteristics, Additional supporting information may be found in the online version of this article.

Section: Resultsmentioning

confidence: 97%

Mechanical and electrical response variation of the polyurethane–tin oxide–carbon nanotube composite microfiber depending on the chemical solution

Cho

Jeong

J. Polym. Sci. Part A: Polym. Chem.

et al. 2018

“…The thermal decomposition of the PU matrix resulted in a two‐stage mass loss between ≈250 and ≈450 °C, which was ascribed to the differences in the thermal decomposition kinetics of the hard (urethane bonding) and soft (polyol) segments of PU chains. [ 11 ] As only small amounts of pH indicator solutions were embedded into fiber pores, the thermal decomposition behavior of impregnated fibers did not significantly deviate from that of the pristine PU‐SnO 2 hollow fiber. However, at temperatures above 450 °C, the halochromic fibers showed a 4–9% increase in the carbon contents of organic materials after degradation compared to the pristine PU‐SnO 2 hollow fiber, which was attributed to the additional production of carbon through the degradation of the pH indicator embedded into fiber pores.…”

Section: Resultsmentioning

confidence: 99%

Elastic Halochromic Fiber as a Reversible pH Sensor

Hong

Choi

Adv Materials Technologies

et al. 2021

Wearable textile colorimetric sensors are extremely effective for expressing danger or warning, as they are non‐invasive and exhibit easily recognizable color changes. However, unlike conventional sensors, these devices are actually worn by individuals and should, therefore, not only detect hazardous chemicals in real time but also maintain the reversibility, durability, and stability of color change upon exposure to sweat, repetitive movement, and environments involving continuous exposure to chemical substances. Herein, a halochromic fiber maintaining excellent pH sensing properties upon continuous exposure to chemical and physical stimuli is fabricated. The fiber surface is rendered hydrophobic by phosphonic acid treatment, and a composite pH indicator dye capable of simultaneously detecting acids and bases is embedded into the fiber pores. The halochromic fiber could accurately detect pH while maintaining a clear color transition even after repeated changes in the acidic–basic environment, returning to the neutral state within several seconds after termination of exposure to the test solution. Thus, the presented technique allows one to significantly improve the reversibility, durability, and stability of color change—a problem faced by conventional wearable sensors—and, thus, greatly contributes to the development of halochromic textile sensors applicable to real‐life work environments.

“…When PU−SnO 2 composite microtubes are heated to a high temperature, a loss of mass in two stages occurs due to the thermal decomposition of the hard and soft segments of PU. 26 At temperatures above 450 °C, a small quantity of SnO 2 residues dispersed within the polymer matrix is left during the degradation of the polymer chains. An increased amount of SnO 2 uniformly anchored to the PU matrix enhances the thermal stability of the latter and consequently improves the thermodynamic properties of the PU−SnO 2 composite microtubes.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Infrared Invisibility Cloak Based on Polyurethane–Tin Oxide Composite Microtubes

Ahn

ACS Appl. Mater. Interfaces

Yeo

et al. 2019

An invisibility cloak based on visible rays with a refractive index similar to that of air can effectively conceal people or objects from human eyes. However, even if an invisibility cloak based on visible rays is used, an infrared (IR) thermography camera can detect the heat (thermal radiation) emitted from different types of objects including living things. Therefore, both visible and IR rays should be shielded using an invisibility cloak produced by an appropriate technology. Herein, we developed a textile cloak that can almost completely conceal people or objects from IR vision. If a person or object is covered with an IR-and thermal-radiation-shielding textile woven with polyurethane (PU)−tin oxide (SnO 2 ) composite microtubes, serving as an IR invisibility cloak, IR and thermal radiation emitted from the person or object can be simultaneously blocked. Furthermore, the IR-and thermal-radiation-shielding characteristics could be improved further by filling the core of the PU−SnO 2 composite microtubes with heat-absorbing materials such as water and paraffin oil in place of air. In addition, the external surface of the IR-and thermal-radiation-shielding textile serving as an IR-reflecting cloak can be waterproofed to enable certain IR-and thermal-radiation-shielding functions under various environmental conditions.