3,6-Disubtituted fluorans containing 4(3H)-quinazolinon-3-yl, diethyl amino groups and their application in reversible thermochromic materials

Patel, Ritesh G.; Patel, Manish P.; Patel, Ranjan G.

doi:10.1016/j.dyepig.2004.08.004

Cited by 11 publications

(4 citation statements)

References 5 publications

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“…Reversible thermochromic substances mainly contain three compounds: an electron‐donating chromatic organic compound (a color former), a compound capable of reversibly accepting an electron (a color developer), and solvent. A certain wavelength of light is absorbed or radiated by the process of electron transfer caused by temperature change, which is apparently reflected as a change in the color of the substance . As shown in Figure d‐(i), three types of thermochromic microcapsule dyes with the color change from dark brown to pink, brown to green, and black to transparent color are selected and used to draw a picture of orchid pattern on the paper‐based actuator.…”

Section: Resultsmentioning

confidence: 99%

Multifunctional Soft Actuators Based on Anisotropic Paper/Polymer Bilayer Toward Bioinspired Applications

Liu

et al. 2019

Adv Materials Technologies

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Designing artificial muscle actuators with diversely complex deformation and multifunction is crucial to the soft robots and their bioinspired applications. Herein, by combing the hygroexpansion and thermal expansion commonly existed in nature, electrically driven paper‐based bilayer actuator is fabricated by a simple printing method. This actuator exhibits large (270°) and anisotropic deformation coupled with features of low‐cost, superior stability, and additional reversible color‐change function. More importantly, the tailoring and heat setting are used to further design the actuator shape, thus obtain multiform deformation (bending, elongation, and folding), and more complicated deformation similar to the arm motion. Based on these actuators, variously bioinspired motions can be constructed. Inspired by the structure of the crystalline lens and ciliary muscle in human eyeball, a biomimetic lens which can change the focal length under electrical stimulation is fabricated. Moreover, W‐shaped robotic arm for manipulating microliquid in 3D direction and catapulting the object into air, in‐pipe spiral robotic arm for pushing objects out of the pipe, and artificial snake capable of deformation and color‐change simultaneously, are also fabricated. This paper‐based actuator together with bioinspired design may open new perspective on the multifunctional smart robots and biomimetic devices.

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Section: Resultsmentioning

confidence: 99%

Multifunctional Soft Actuators Based on Anisotropic Paper/Polymer Bilayer Toward Bioinspired Applications

Liu

et al. 2019

Adv Materials Technologies

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“…In organic thermochromic materials, leuco dyes are highly interested and changed from a colorless to a colored state by accepting a proton. Rhodamine B derivatives, , fluorans, − spiropyrans, − and crystal violet lactone are some important examples of leuco dye compounds that are generally used in the preparation of thermochromic materials. , Thermochromism is classified into reversible and irreversible categories, where the reversible systems have gained more attention because of their extensive applications based on temperature fluctuations during the day and in different seasons, such as in the military, construction, anticounterfeiting, sensors, etc . For the reversible coloration–decoloration of organic leuco dyes, a three-component system including leuco dye, solvent, and developer is required. , Color developers play the role of chroma, and are often from the category of phenolics (a weak acid such as Bisphenol A), aromatic amines, lauryl gallate, ethyl gallate, carboxylic acids, and Lewis acids that are usually used for the solid state of the thermochromic materials. ,− Strong proton donors, such as hydrochloric acid, are suitable for both liquid and solid states, and they provide a proton to the color former.…”

Section: Introductionmentioning

confidence: 99%

“…Rhodamine B derivatives, 10,11 fluorans, 12−14 spiropyrans, 15−18 and crystal violet lactone 19 are some important examples of leuco dye compounds that are generally used in the preparation of thermochromic materials. 20,21 Thermochromism is classified into reversible and irreversible categories, where the reversible systems have gained more attention because of their extensive applications based on temperature fluctuations during the day and in different seasons, such as in the military, construction, anticounterfeiting, sensors, etc. For the reversible coloration− decoloration of organic leuco dyes, a three-component system including leuco dye, solvent, and developer is required.…”

Section: Introductionmentioning

confidence: 99%

Thermal-Induced Chromism and Fluorescence Emission of Rhodamine B-Containing Polymers with Different Polarities: Tracking Temperature and Development of Thermochromic Labels

Babazadeh-Mamaqani,

Mohammadi-Jorjafki,

Alipour-Fakhri

et al. 2023

Macromolecules

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Thermochromic polymers, as a highly applicable intelligent category of innovative materials, are capable of changing their color with temperature variations. Different characteristics of the matrix and specially its polarity can be influential factors in the responsivity of thermochromic polymers. In this study, polystyrene, poly(methyl methacrylate), and poly(dimethylaminoethyl methacrylate) with different polarities were synthesized via reverse atom transfer radical polymerization. Thermochromic polymers were prepared by physical incorporation of the N-(rhodamine-B)lactam-ethylenediamine leuco dye and HCl color developer into the three polymers. The effect of polarity of the polymers on their thermochromism and fluorescence properties was investigated. The thermochromic polymers changed their color from colorless to a colored state with increasing temperature due to the intermolecular proton transfer in the system. UV−vis and fluorescence spectroscopies were used to evaluate the thermochromism and fluorescence properties of the polymer systems, respectively, at different temperatures. The intensity of absorption and emission of the thermochromic polymers increases with increasing temperature, where increasing polarity of the polymer matrix has an opposite effect on the intensity of absorption and emission. The change in color with temperature variation was detectable with the naked eye for the three polymer samples. In addition, investigation of the fatigue resistance and also response and recovery times of the samples showed temperature-sensing ability of the samples. These results showed that all samples have high responsivity and coloration for at least 10 heating−cooling cycles. Biocompatible thermochromic cellulosic papers were also fabricated, which showed irreversible coloration at different temperatures due to the removing solvent. Chromic labels with the ability of irreversible thermal-induced chromism was used as preservation taggants, which indicate that the food materials were kept at the right or wrong temperature. Therefore, they have a high potential for applications in various fields, such as temperature sensors, condition preservation taggant or labels for food or cosmetic, and anticounterfeiting inks.

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“…When the temperature is lower than this value, the original color is restored [4]. The thermochromic coating can not only be used for surface temperature measurement [5], 3D printing [6], overtemperature warning [7], and anti-counterfeiting identification [8], but also for decoration [9]. At present, most of the thermochromic coatings are prepared by adding thermochromic materials into the coatings [10].…”

Section: Introductionmentioning

confidence: 99%

Effect of Coating Process on Performance of Reversible Thermochromic Waterborne Coatings for Chinese Fir

2020

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The effect of the coating process on the properties of reversible thermochromic waterborne coating on the surface of Chinese fir was examined. The results demonstrated that the most critical process parameter affecting the color difference and gloss of the coating was the way of adding thermochromic ink. The coating process had little influence on the adhesion, impact resistance adding, liquid resistance, and original properties of the coating. There was no obvious gloss variation in the coating under different coating processes. For the (3+3) layered coatings, when the thermochromic ink was added to the topcoats, the discoloration performance was the most obvious and the comprehensive performance of coating was better. Meanwhile, the gloss was 55.6%, the adhesion grade was grade 0, the impact resistance was 5.0 kg·cm, the liquid resistance grade of the coating to sodium chloride, ethanol and detergent was grade 1, and the liquid resistance grade to red ink was grade 3. The discoloration performance of the coating was stable under the conditions of aging and time change. This study provides new insight into preparing thermochromic intelligent waterborne wood coatings with potential practical applications on Chinese fir wood surfaces, and also lays a foundation for its application in furniture engineering.Coatings 2020, 10, 223 2 of 15 consumption. Wang et al. [14] prepared a poly-3,4-ethylene dioxythiophene coating, which provided a new idea for the preparation of a highly conductive coating with an obvious thermochromic effect on the textile pattern. Pan et al. [15] prepared the thermochromic vanadium dioxide films co-sputtered by vanadium and stainless-steel. It has good durability in high-temperature environments, whether humid or dry. The thermochromic coatings in these studies are chiefly used in the fields of windows, buildings, fabrics, infrared sensors, etc., while research on the thermochromic waterborne coatings applied to the surface of furniture and wood is relatively rare.Organic reversible thermochromic materials are mainly composed of chromogenic agents and solvent, which have significant characteristics in the temperature of color change, color combination, and color contrast before and after color change [16]. Therefore, compared with inorganic and liquid crystal thermochromic materials, organic thermochromic materials are more popular because of their sensitive color change, rich color, good durability, long shelf life, and low cost. Organic reversible thermochromic ink has the advantages of convenient detection. They are fast, accurate, have no need for additional auxiliary equipment, and have a broad application prospect in thermochromic coatings [17]. Chinese fir is highly applied to construction, in bridges, house furnishings, woodwork, and other domains [18], on account of its light weight, good machinability, resistance to deforming, insect-resistance, anti-corrosion, and other excellent properties [19]. Waterborne wood coatings are free of volatile organic compounds (VOCs) [20] and air co...

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3,6-Disubtituted fluorans containing 4(3H)-quinazolinon-3-yl, diethyl amino groups and their application in reversible thermochromic materials

Cited by 11 publications

References 5 publications

Multifunctional Soft Actuators Based on Anisotropic Paper/Polymer Bilayer Toward Bioinspired Applications

Multifunctional Soft Actuators Based on Anisotropic Paper/Polymer Bilayer Toward Bioinspired Applications

Thermal-Induced Chromism and Fluorescence Emission of Rhodamine B-Containing Polymers with Different Polarities: Tracking Temperature and Development of Thermochromic Labels

Effect of Coating Process on Performance of Reversible Thermochromic Waterborne Coatings for Chinese Fir

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