Quantitative and high-resolution mechanical pressure sensing functions of mechanochromic fluorenylidene-acridane

Ogumi, Keisuke; Nagata, Kohki; Takimoto, Yuki; Mishiba, Kentaro

doi:10.1039/d2tc01988d

Cited by 4 publications

(5 citation statements)

References 38 publications

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“…This phenomenon is explained by the photophysical changes of FAs derived from ground-state mechanochromism. Further, in addition to the above mechanical pressure sensing, we found that FAs exhibit a response to alcohol 34 . An FA that has dimethoxy substituents on the fluorene unit could be returned from the blue color caused by mechanical pressure to its original yellow color by use of alcohol (Fig.…”

Section: Introductionmentioning

confidence: 53%

Inkjet printing of mechanochromic fluorenylidene-acridane

Ogumi

Nagata

Takimoto

et al. 2022

Sci Rep

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In mechanochromic material research, a serious problem is that mechanical treatment cannot be applied to the materials because of their responsiveness to stimuli. Inkjet printing is a useful solution deposition method for electronics, but materials must be processed to be suitable for an inkjet printer. Fluorenylidene-acridane (FA) exhibits ground-state mechanochromism with visual color changes and responds not only to mechanical pressure but also to alcohol. Alcohol inhibits the color change induced by mechanical stimulation because the mechanochromism of FA is based on a conformational change in its molecular structure. This phenomenon suggests that the mechanochromism of FA can be controlled using alcohol. For use in inkjet printing, minute particles of FA obtained by bead milling in ethanol were investigated for uniformity and size by scanning electron microscopy and gas adsorption measurement. Also, ink containing FA particles was prepared and examined for physical properties such as viscosity and surface tension. It was confirmed that the inkjet-printed pattern demonstrated visual color changes between yellow and green in response to mechanical pressure and alcohol. This report describing the control of mechanochromism and its specific application is expected to contribute to broadening the mechanochromic materials research field.

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Section: Introductionmentioning

confidence: 53%

Inkjet printing of mechanochromic fluorenylidene-acridane

Ogumi

Nagata

Takimoto

et al. 2022

Sci Rep

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“…To assess the response to mechanical pressure, we employed diffuse reflectance UV–vis spectroscopy (Figures b, S7b, and S8b). Focusing on the peak in the 500–600 nm wavelength range, which includes green and yellow, we observed a decrease in the peak height of the reflectance value with increasing mechanical pressure. Thus, we generated a calibration curve for the relationship between the mechanical pressure and the peak height of the reflectance value.…”

Section: Resultsmentioning

confidence: 99%

“…Among the FA derivatives in previous reports, FA, which prefers the folded conformer due to the electron-donating methoxy group, was employed. , FA was synthesized in six steps using commercially available materials. In the final step, FA was obtained by the Barton–Kellogg reaction using diazofluorenylidene and thioacridane (Scheme S1).…”

Section: Methodsmentioning

confidence: 99%

“…Previously, we quantitatively investigated the mechanochromism using fluorenylidene-acridane (FA), which displays a visible color change as shown in Figure a. − FA undergoes a conformational change from a folded to a twisted conformer in response to mechanical pressure. This structural change facilitates charge transfer from the acridane unit to the fluorenylidene unit, resulting in unique ground-state mechanochromism that manifests as a visible color change (Figure b).…”

Section: Introductionmentioning

confidence: 99%

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Color-Changing Paper: Cellulose Nanofiber Films Incorporating Mechanochromic Fluorenylidene-Acridane

Ogumi,

Arakawa,

Okudera

et al. 2024

ACS Appl. Eng. Mater.

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Color-changing paper using a cellulose nanofiber (CNF) film with mechanical pressure-sensing capability was produced using mechanochromic fluorenylidene-acridane (FA), which exhibits color change upon mechanical pressure. This flexible film exhibits a visible color change from yellow to green in response to a mechanical force. Surface investigations, such as scanning electron microscopy and contact angle analysis, revealed that the repeatability of the color change was dependent on the CNF diameter. Furthermore, the FA-CNF film exhibited a linear response to mechanical pressure within the range of 25−300 MPa, as quantitatively measured by mechanochromism using a combination of nanoimprint testing and UV−vis spectroscopy. This measurement suggested that the flexibility of the film improved mechanochromic sensitivity. When compared with the conventional method using UV−vis spectroscopy, a simpler image processing method employing CYM color analysis was able to visualize the distribution of the mechanical pressure.

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“…The following are the previous studies on color change according to the state of an object: When a mechanochromic fluorenylidene-acridane film generated by vacuum evaporation is mechanically stimulated, the molecular structure is deformed, and the film changes color from yellow to green [6]. Perovskite nanosheet hydrogels with mechanochromic structural colors instantly change from longwavelength orange to short-wavelength blue when a force is applied [7].…”

Section: Introductionmentioning

confidence: 99%

Ajisai: A Structure That Matches the Relationship Between Force and Color to Human Perception

Hyodo,

Yamada

2024

IEEE Robot. Autom. Lett.

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Humans find it difficult to perceive visually the level of force exerted on an object by a robot operating with positional control. According to research, humans perceive colors in terms of weight following the order of yellow, green, blue, and red, clockwise on the hue circle. We believe that by developing a structure that changes colors in this specific order, we can achieve visual force transmission that aligns with the relationship between force and color as perceived by humans. In this study, we used the photoelasticity of an anisotropic transparent material, which changes color depending on the applied force when sandwiched between two polarizing plates. The material is dumbbell shaped, which ensures equalization of the applied force. Based on this, we have developed a structure called Ajisai, which is powered by artificial muscles and whose colors change in response to applied force to match human perception.

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Quantitative and high-resolution mechanical pressure sensing functions of mechanochromic fluorenylidene-acridane

Abstract: In the field of mechanochromic materials which respond to external stimulation, although observation of mechanochromism is an essential effort, numerical data almost have not been obtained. The quantitative mechanical pressure...

Cited by 4 publications

References 38 publications

Inkjet printing of mechanochromic fluorenylidene-acridane

Inkjet printing of mechanochromic fluorenylidene-acridane

Color-Changing Paper: Cellulose Nanofiber Films Incorporating Mechanochromic Fluorenylidene-Acridane

Ajisai: A Structure That Matches the Relationship Between Force and Color to Human Perception

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