Highly contrastive, real-time modulation of light intensity by reversible stress-whitening of spontaneously formed nanocomposites: application to wearable strain sensors

Park, Seung Koo; Yun, Sungryul; Hwang, Geonwoo; Choi, Meejeong; Kim, Dong Wook; Lee, Jong-Moo; Park, Bong Je; Nam, Saekwang; Mun, Heeju; Mun, Seongcheol; Lim, Jeong Mook; Shin, Eun Jin; Kyung, Ki-Uk; Park, Suntak

doi:10.1039/d1tc00256b

Cited by 3 publications

(1 citation statement)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The phenomenon of stress whitening is well known in polymers subjected to impact and stretching. − Whitening results from void formation (particle-matrix interface detachment) or deformation. The extent of stress whitening in HIPS/PPE/PS/PB-g-PS blend impact specimens with different matrix compositions is shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

Mechanical Properties and Deformation Mechanism of Bimodal-Rubber-Particle-Toughened Polyphenylene Ether/Polystyrene Blends

Wang

Ren

et al. 2022

ACS Appl. Polym. Mater.

View full text Add to dashboard Cite

A core−shell polybutadiene-graft-polystyrene (PB-g-PS) copolymer with a core−shell ratio of 70/30 (wt/wt) was synthesized by redox-initiated emulsion graft polymerization. Compatible polymers of polyphenylene ether (PPE) and polystyrene (PS) blend were toughened by the addition of high-impact polystyrene (HIPS) and the PB-g-PS copolymer, and the content of PB rubber in the whole matrix was kept at 17.4 wt %. The influence of the matrix composition and synergistic toughening effect of different-sized rubber particles on the mechanical properties, morphology, and deformation mechanism of HIPS/PPE/PS/PBg-PS blends was investigated. The results showed that submicrometer-sized PB-g-PS core−shell particles (318 nm) and large-sized HIPS rubber particles (1∼5 μm) had an excellent synergistic toughening effect, which could significantly improve the toughness of the PPE/PS blends, from 47 to 672 J/m. The impact strength, elongation at break, tensile strength, and degree of stress whitening of the blends increased with the increase of PPE content in the matrix, and when the content of PPE increased from 10 to 20 wt %, the brittle−ductile transition occurred. Transmission electron microscopy and scanning electron microscopy results showed that when the PPE content in the blends was low, the PB-g-PS copolymers would agglomerate and be unevenly distributed in the matrix, and the deformation mechanism of the blend was multiple crazing. With increased PPE content, the distribution of the PB-g-PS copolymers was significantly improved, and the deformation mechanism combined crazing and shear yield. With the further increase of PPE content, the rubber particles in the matrix became extensively elongated, and the deformation mechanism was wholly transformed to shear yield.

show abstract

Section: Resultsmentioning

confidence: 99%

Mechanical Properties and Deformation Mechanism of Bimodal-Rubber-Particle-Toughened Polyphenylene Ether/Polystyrene Blends

Wang

Ren

et al. 2022

ACS Appl. Polym. Mater.

View full text Add to dashboard Cite

show abstract

Compression-sensitive smart windows: inclined pores for dynamic transparency changes

Chen,

Chang,

Lee

et al. 2024

Nat Commun

View full text Add to dashboard Cite

Smart windows, capable of tailoring light transmission, can significantly reduce energy consumption in building services. While mechano-responsive windows activated by strains are promising candidates, they face long-lasting challenges in which the space for the light scatterer’s operation has to be enlarged along with the window size, undermining the practicality. Recent attempts to tackle this challenge inevitably generate side effects with compromised performance in light modulation. Here, we introduce a cuttlefish-inspired design to enable the closing and opening of pores within the 3D porous structure by through-thickness compression, offering opacity and transparency upon release and compression. By changing the activation mode from the conventional in-plane to through-thickness direction, the space requirement is intrinsically decoupled from the lateral size of the scatterer. Central to our design is the asymmetry of pore orientation in the 3D porous structure. These inclined pores against the normal direction increase the opaqueness upon release and improve light modulation sensitivity to compression, enabling transmittance regulation upon compression by an infinitesimal displacement of 50 μm. This work establishes a milestone for smart window technologies and will drive advancements in the development of opto-electric devices.

show abstract

Mechanoresponsive scatterers for high-contrast optical modulation

et al. 2021

View full text Add to dashboard Cite

Smart chromatic materials with optical transmittances that can be modified by light scattering upon external stimuli are attracting extensive interest because of their appealing applications in smart windows, privacy protection, electronic displays, etc. However, the development of these scatterers, which are mostly activated by electric fields, is hindered by their intrinsic energy consumption, slow responses, and poor stability. Recently, mechanoresponsive scatterers based on a strain-driven reconfiguration of the surface or internal structure have emerged, featuring fast responses and a simple composition/fabrication. Because there is no energy consumption to maintain the transparency/opacity, this novel scheme for scatterers holds great promise to break the existing bottleneck. This article presents recent advances in the development of mechanoresponsive scatterers and compares different structural design strategies. The scatterers are categorized into 2D, 3D, and other types according to the dimensions of their functioning structures. The fabrication methods, mechanisms, and relationships between the structural parameters and optical modulating performances are discussed for each category. Next, the potential applications of these scatterers are outlined. Finally, the advantages and disadvantages of the mainstream 2D and 3D categories are summarized, followed by a perspective on future research directions.

show abstract

Highly contrastive, real-time modulation of light intensity by reversible stress-whitening of spontaneously formed nanocomposites: application to wearable strain sensors

Abstract: Stress-whitening is generally regarded as a sign of irreversible elasticity failure of polymer materials. Here, we report for the first time that in stark contrast to the conventional insight, the...

Cited by 3 publications

References 47 publications

Mechanical Properties and Deformation Mechanism of Bimodal-Rubber-Particle-Toughened Polyphenylene Ether/Polystyrene Blends

Mechanical Properties and Deformation Mechanism of Bimodal-Rubber-Particle-Toughened Polyphenylene Ether/Polystyrene Blends

Compression-sensitive smart windows: inclined pores for dynamic transparency changes

Mechanoresponsive scatterers for high-contrast optical modulation

Contact Info

Product

Resources

About