The Electropolymerization and Characterizations of Fluorescent Dye Doped Poly(3,4-ethylenedioxythiophene)

2014 ◽  
Vol 552 ◽  
pp. 291-297
Author(s):  
Xin Li ◽  
Fei Yue Liang ◽  
Cong Ju Li

The electrochromic properties of an electrochemical polymerized composite consisted of poly (3,4-ethylenedioxythiophene) doped with fluorescent yellow dye (PEDOT-FY) are reported. The structures of PEDOT-FY were characterized via cycle voltammograms, spectroelectrochemistry and colorimetric analysis. Film of the PEDOT-FY composites with different FY concentrations appears multi-color changes, such as blue violet↔brillant blue, aubergine↔blue grey, magenta↔ aquamarine blue, orange-yellow↔grass-green, claybank↔moss green in the neutral state and the oxidized state respectively, which are different from the pure PEDOT of dark blue (-0.8V) and light blue (1.0V). The response time reaching 90% of the full optical contrast of PEDOT-FY was 3.4s for the oxidation process and 2.6s for the reverse reduction process when the [EDOT]/[FY] is 1:2, however, when the FY concentration decreased to [EDOT]/[FY] =1:0.01, the response time reduced to 1.9s and 1.7s for the oxidation and reduction process respectively, which is equal to that of the pure PEDOT. Additionally, the colorimetric analysis results show that components of yellow and red in PEDOT-FY films become stronger than pure PEDOT film at the whole electrochromic process. It is shown that acid dye doping is an effective method to broaden the color change range of the electrochromic mateials.

2014 ◽  
Vol 665 ◽  
pp. 300-306
Author(s):  
Xin Li ◽  
Cong Ju Li

A novel kind of poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT/PSS) composite was synthesized through chemical oxidation polymerization in the presence of fluorescent yellow GG (FYGG) as the functional co-dopant and Poly(vinyl alcohol) as the film-forming additives. The as-prepared composite was found combined with fluorescent function and electrochromic property. Film of the PEDOT/PSS-FYGG composites switches from green in the reduction state to blue-green in the oxidized state, which is different from the pure PEDOT/PSS of light blue (-0.2V) and dark blue (0.8V). Because of the big molecule of FYGG as the dopant, the response time reaching 90% of the full optical contrast of PEDOT/PSS-FYGG was 1.77s for the coloration process and 1.78s for the reverse bleach process, which is a little slower than the pure PEDOT/PSS. Additionally, PEDOT/PSS-FYGG film presents a good stability. It is shown that acid dye doping is an effective method to broaden the color change range of the electrochromic mateials.


Holzforschung ◽  
2011 ◽  
Vol 65 (3) ◽  
Author(s):  
Miyuki Matsuo ◽  
Misao Yokoyama ◽  
Kenji Umemura ◽  
Junji Sugiyama ◽  
Shuichi Kawai ◽  
...  

Abstract The color properties of aging wood samples from historical buildings have been compared with those of recent wood samples that were heat treated at temperatures ranging from 90°C to 180°C. The results of kinetic analysis obtained by the time-temperature superposition method showed that the color change during natural aging was mainly due to a slow and mild oxidation process. In other words, heat treatment could accelerate the changes in wood color that occur during aging. In one sample, the color change (ΔE* ab ) after 921 years at ambient temperature was almost equivalent to that of heating (artificial aging) approximately for 6.7 h at 180°C. The results have been interpreted that the aging and the subsequent change in wood color begin at the time of tree harvesting.


The Analyst ◽  
2019 ◽  
Vol 144 (4) ◽  
pp. 1361-1368 ◽  
Author(s):  
Yixun Gao ◽  
Dehai Mu ◽  
Peng Guan ◽  
Pengran Guo ◽  
Huacan Song

A fluorene substituted vinyl-SiO microsphere performs a rapid fluorescence color change via oxidation with highly selective PETN catalysis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiyu Sun ◽  
Wei Wu ◽  
Limei Tian ◽  
Wei Li ◽  
Fang Zhang ◽  
...  

AbstractNot only does the Dynastes tityus beetle display a reversible color change controlled by differences in humidity, but also, the elytron scale can change color from yellow-green to deep-brown in specified shapes. The results obtained by focused ion beam-scanning electron microscopy (FIB-SEM), show that the epicuticle (EPI) is a permeable layer, and the exocuticle (EXO) is a three-dimensional photonic crystal. To investigate the mechanism of the reversible color change, experiments were conducted to determine the water contact angle, surface chemical composition, and optical reflectance, and the reflective spectrum was simulated. The water on the surface began to permeate into the elytron via the surface elemental composition and channels in the EPI. A structural unit (SU) in the EXO allows local color changes in varied shapes. The reflectance of both yellow-green and deep-brown elytra increases as the incidence angle increases from 0° to 60°. The microstructure and changes in the refractive index are the main factors that influence the process of reversible color change. According to the simulation, the lower reflectance causing the color change to deep-brown results from water infiltration, which increases light absorption. Meanwhile, the waxy layer has no effect on the reflection of light. This study lays the foundation to manufacture engineered photonic materials that undergo controllable changes in iridescent color.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2569
Author(s):  
Mia Kurek ◽  
Nasreddine Benbettaieb ◽  
Mario Ščetar ◽  
Eliot Chaudy ◽  
Maja Repajić ◽  
...  

Chitosan and pectin films were enriched with blackcurrant pomace powder (10 and 20% (w/w)), as bio-based material, to minimize food production losses and to increase the functional properties of produced films aimed at food coatings and wrappers. Water vapor permeability of active films increased up to 25%, moisture content for 27% in pectin-based ones, but water solubility was not significantly modified. Mechanical properties (tensile strength, elongation at break and Young’s modulus) were mainly decreased due to the residual insoluble particles present in blackcurrant waste. FTIR analysis showed no significant changes between the film samples. The degradation temperatures, determined by DSC, were reduced by 18 °C for chitosan-based samples and of 32 °C lower for the pectin-based samples with blackcurrant powder, indicating a disturbance in polymer stability. The antioxidant activity of active films was increased up to 30-fold. Lightness and redness of dry films significantly changed depending on the polymer type. Significant color changes, especially in chitosan film formulations, were observed after exposure to different pH buffers. This effect is further explored in formulations that were used as color change indicators for intelligent biopackaging.


2012 ◽  
Vol 37 (5) ◽  
pp. 526-531 ◽  
Author(s):  
CRG Torres ◽  
CF Ribeiro ◽  
E Bresciani ◽  
AB Borges

SUMMARY The aim of the present study was to evaluate the effect of 20% and 35% hydrogen peroxide bleaching gels on the color, opacity, and fluorescence of composite resins. Seven composite resin brands were tested and 30 specimens, 3-mm in diameter and 2-mm thick, of each material were fabricated, for a total of 210 specimens. The specimens of each tested material were divided into three subgroups (n=10) according to the bleaching therapy tested: 20% hydrogen peroxide gel, 35% hydroxide peroxide gel, and the control group. The baseline color, opacity, and fluorescence were assessed by spectrophotometry. Four 30-minute bleaching gel applications, two hours in total, were performed. The control group did not receive bleaching treatment and was stored in deionized water. Final assessments were performed, and data were analyzed by two-way analysis of variance and Tukey tests (p<0.05). Color changes were significant for different tested bleaching therapies (p<0.0001), with the greatest color change observed for 35% hydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (p<0.0001) and bleaching therapy (p=0.0016) used. No significant differences in fluorescence between different bleaching gel concentrations were detected by Tukey test. The greatest fluorescence alteration was detected on the brand Z350. It was concluded that 35% hydrogen peroxide bleaching gel generated the greatest color change among all evaluated materials. No statistical opacity changes were detected for all tested variables, and significant fluorescence changes were dependent on the material and bleaching therapy, regardless of the gel concentration.


BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5574-5585
Author(s):  
Intan Fajar Suri ◽  
Jong Ho Kim ◽  
Byantara Darsan Purusatama ◽  
Go Un Yang ◽  
Denni Prasetia ◽  
...  

Color changes were tested and compared for heat-treated Paulownia tomentosa and Pinus koraiensis wood treated with hot oil or hot air for further utilization of these species. Hot oil and hot air treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 h. Heat-treated wood color changes were determined using the CIE-Lab color system. Weight changes of the wood before and after heat treatment were also determined. The weight of the oil heat-treated wood increased considerably but it decreased in air heat-treated wood. The oil heat-treated samples showed a greater decrease in lightness (L*) than air heat-treated samples. A significant change in L* was observed in Paulownia tomentosa. The red/green chromaticity (a*) of both wood samples increased at 180 and 200 °C and slightly decreased at 220 °C. The yellow/blue chromaticity (b*) in both wood samples increased at 180 °C, but it rapidly decreased with increasing treatment durations at 200 and 220 °C. The overall color change (ΔE*) in both heat treatments increased with increasing temperature, being higher in Paulownia tomentosa than in Pinus koraiensis. In conclusion, oil heat treatment reduced treatment duration and was a more effective method than air heat treatment in improving wood color.


2016 ◽  
Vol 10 (1) ◽  
pp. 516-521 ◽  
Author(s):  
Vanessa Dias da Silva ◽  
Eduardo Martinelli S de Lima ◽  
Caroline Dias ◽  
Leandro Berni Osório

Proposition: The purpose of this study was to evaluate in vitro the color changes of esthetic orthodontic elastomeric ligatures of different shades when exposed to four food colorings commonly found in the diet of patients. Materials and Methods: The sample consisted of esthetic orthodontic elastomeric ligatures in the colors pearl, pearl blue, pearl white and colorless, which were immersed for 72 hours in five different solutions: distilled water (control group), coffee, tea, Coca-Cola ® and wine. The color changes of the esthetic orthodontic elastomeric ligatures were measured with the aid of a spectrophotometer, at T1 - as provided by the manufacturer; and T2 - after colorings process. Results: The results indicated that the esthetic orthodontic elastomeric ligatures of all initial hues are susceptible to pigmentation. Among the evaluated colors, all changed the finished look and the color of the samples tested. In ascending order, the color of the samples was as follows: distilled water, Coca-Cola®, black tea, wine and coffee. Conclusion: The substances that have a greater potential for pigmentation in esthetic orthodontic elastomeric ligatures were black tea, wine and coffee, respectively. All shades of esthetic orthodontic elastomeric ligatures are susceptible to color change.


Foods ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 7 ◽  
Author(s):  
Edgar Cambaza ◽  
Shigenobu Koseki ◽  
Shuso Kawamura

Deoxynivalenol (DON) is a well-known mycotoxin, responsible for outbreaks of gastrointestinal disorders in Japan. Fusarium graminearum, a parasite of cereal crops, produces this toxin and this is one of the reasons why it is important to understand its metabolism. It is possible to predict the mold’s color change and the quantity of DON synthesized throughout its lifecycle. Furthermore, aw has been found to affect the amount of DON. This study aimed to analyze the potential of F. graminearum surface color as a predictor of DON concentration at aw = 0.94, 0.97, and 0.99. Thus, 36 specimens were incubated at 25 °C, 12 at each aw. After 4, 8, 12, and 16 days, three specimens from each aw were collected for color analysis and DON quantification. For color analysis, photos were taken and red, green and blue (RGB) channels were measured on ImageJ software. DON was quantified through liquid chromatography (HPLC). Color changes were only observed at aw = 0.99 because at lower aw the molds presented high growth of white mycelium. Yet, DON increased in all cases. It was only possible to relate the colors with DON concentration at aw = 0.99, where they presented inverse proportionality.


2020 ◽  
Vol 14 (01) ◽  
pp. 085-091
Author(s):  
Sedighe Sadat Hashemikamangar ◽  
Farnoosh Hoseinpour ◽  
Nazanin Kiomarsi ◽  
Mehrzad Gholampour Dehaki ◽  
Mohammad Javad Kharazifard

Abstract Objectives This study aimed to assess the effect of an optical whitening toothpaste on color stability of microhybrid, nanofilled, and microfilled composite resins and resin-modified glass ionomer (RMGI) cement in comparison of two other toothpastes. Materials and Methods In this experimental study, disc-shaped composite samples were fabricated. The samples were then polished using silicon carbide papers. Twenty-seven samples of each material were fabricated and subjected to colorimetry using a spectrophotometer. Each group of material was then divided into three subgroups for the application of conventional whitening and whitening containing blue covarine toothpastes. One operator brushed the samples with an electric soft toothbrush with circular motion twice a day, each time for 30 seconds. Colorimetry was performed at 0, 1, 7, 30, and 90 days. Statistical Analysis Two-way analysis of variance (ANOVA), one-way ANOVA, and Tukey’s honestly significant difference (HSD) test were used for statistical analysis. Results The interaction effect of type of restorative material and time on ∆E was not significant at baseline or 1 day (p > 0.05). The effect of type of toothpaste on ∆E was not significant at baseline or 1 day (p = 0.78) but the effect of type of material was significant (p < 0.05). The toothpastes had significantly different effects on ∆E of Z250 at all time points (p < 0.05) except for ∆E0–30 (p = 0.106). The toothpastes had significantly different effects on ∆E of Z350 and Gradia at all time points (p < 0.05). The same was true for RMGI except for ∆E0–7 (p = 0.43) and ∆E0–90 (p = 0.52). The majority of color changes caused by toothpastes were not clinically perceivable (∆E < 3.3), except for ∆E0–90 by the whitening toothpaste (∆E = 9), ∆E0–90 by the conventional toothpaste for Z350 (∆E = 3.9), and ∆E0–1 by the whitening toothpaste for RMGI (∆E = 3.7). Conclusion The color change of all composite samples was not clinically perceivable (<3.3) at all time points, which shows that the tested toothpastes do not cause a significant change in color of composite materials.


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