Structural properties of photochromic polyPCDA: A computational study

Gellini, Cristina; Muniz‐Miranda, Maurizio; Salvi, Pier Remigio; Alloisio, Marina; Dellepiane, G.

doi:10.1016/j.molstruc.2010.11.021

Cited by 8 publications

(11 citation statements)

References 32 publications

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“…The vis‐absorption spectrum of EBT3 films results from the absorption properties of two phases of the PDA polymer, i.e., the blue phase and the red phase . These polymer color phases represent distinct geometrical conformations of the polymer backbone which are discernible by their color . The blue phase strongly absorbs in the red region of the visible spectrum resulting in a bluish appearance, and the red phase strongly absorbs blue light giving a reddish color.…”

Section: Methodsmentioning

confidence: 99%

Modeling the dose dependence of the vis-absorption spectrum of EBT3 GafChromic™ films

et al. 2017

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Purpose: The aim of this work was to model the dose dependence of the darkening of GafChromic TM EBT3 films by combining the optical properties of the polydiacetylene polymer phases, and a modified version of the single-hit model, which will take the stick-like shape of the monomer microcrystals into account. Second, a comparison is made between the quantification of the film darkening by flatbed scanning and by UV-vis absorption spectroscopy. Method: GafChromic TM EBT3 films were irradiated with a 6 MV photon beam at dose levels between 0 and 50 Gy. The radiation-induced darkening of the films is quantified by a flatbed scanner, and by UV-vis absorption spectroscopy in the wavelength range of 220-750 nm. From the UV-vis absorption spectra, the contribution of each polymer phase to the absorbance was deduced. Next, the dose dependence of the polymer content is described by a modified single-hit model where the size distribution of polymerizable centers is approximated by way of the size distribution of the monomer microcrystals in the film. Results: The absorption properties of the film can be accurately quantified by UV-vis spectroscopy for dose levels between 0 and 10 Gy. Over 10 Gy, the absorption spectrum saturates due to the limited sensitivity of the spectrometer. The modified single-hit model was successful in describing the increasing polymer concentration with radiation dose, using a log-normal distribution for the length of the stick-like monomer microcrystals. The dose dependence of the polymer content, deduced from the UV-vis absorption spectrum, differs from that of the flatbed scanning method and is more sensitive to changes in dose. Conclusion: The dose dependence of the polymer concentration can be modeled by taking into account the distribution of active centers using the microstructure of the active layer for dose levels between 0 and 10 Gy. The dissimilar dose dependence of the polymer concentration and the absorbance must be accounted for when modeling darkening from the kinetics of the photopolymerization reaction.

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Section: Methodsmentioning

confidence: 99%

Modeling the dose dependence of the vis-absorption spectrum of EBT3 GafChromic™ films

et al. 2017

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“…15 Density functional theory studies by Nannucci et al 16 and Filhol et al 17 indicated that the color exhibited by polydiacetylenes strongly depends on the torsion angle between consecutive repeat units. In that sense, the polymer color phases are distinct geometrical conformations of the polymer backbone, and Gellini et al 18 showed that the bluishgreen, blue, and red phases of polyPCDA correspond to F. 1.…”

Section: Introductionmentioning

confidence: 99%

A spectroscopic study of the chromatic properties of GafChromic™EBT3 films

et al. 2016

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“…The relative stability of the torsional conformation to the original conformation determines the color‐change properties of the PDA and PDA‐M 2+ crystals, such as color, responsivity, and reversibility. In a previous report, the calculational study showed the relationship between the torsional angle of the PDA main chain ( θ ) and the energy . The report indicates that the original conformation without the torsional PDA main chain, namely θ = 0°, is energetically the most stable .…”

Section: Resultsmentioning

confidence: 95%

“…The report indicates that the original conformation without the torsional PDA main chain, namely θ = 0°, is energetically the most stable . The torsion of the PDA main chain induces the higher energy states depending on the θ …”

Section: Resultsmentioning

confidence: 97%

“…In a previous report, the calculational study showed the relationship between the torsional angle of the PDA main chain ( θ ) and the energy . The report indicates that the original conformation without the torsional PDA main chain, namely θ = 0°, is energetically the most stable . The torsion of the PDA main chain induces the higher energy states depending on the θ …”

Section: Resultsmentioning

confidence: 97%

See 1 more Smart Citation

Intercalation‐Induced Tunable Stimuli‐Responsive Color‐Change Properties of Crystalline Organic Layered Compound

Okaniwa

Oaki

Imai

2016

Adv Funct Materials

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compound ( Figure 1 ). If the intercalation of guests changes crystal structures of the organic layered compound, the dynamic properties can be tuned by not molecular design but intercalation. In the present work, temperature-and stress-induced color-change properties of a crystalline layered PDA were tuned by intercalation of guest metal ions in the layered structure.PDAs with π -conjugated backbone are synthesized by polymerization of diacetylene (DA) monomers. [21][22][23] For example, 10,12-Pentacosadiynoic acid (PCDA) forms the layered crystal structure with the lamellar bilayer molecular assembly (Figure 1 ). When the distance between the diacetylene moieties is shorter than 0.5 nm in the assembled states, the topochemical polymerization without changes of the molecular arrangement is achieved by irradiation of UV light, X-ray, and γ-ray. [ 24,25 ] PDAs have a wide variety of applications, such as transistors and sensors. [26][27][28][29][30][31][32][33][34][35][36] One of the most characteristic properties of PDAs is stimuli-responsive color changes. [ 24,25 ] However, the stimuli-responsive properties of PDAs, such as color, responsivity, and reversibility, were not tuned by simple approaches except molecular design. In general, the blue color of PDA derivatives irreversibly turns to the red one by application of external stimuli, such as temperature rise. Since the external stimuli cause the torsion of the PDA main chains, shortening of the conjugation length induces the irreversible color changes. [26][27][28][29][30] The reversible color change was observed on the PDAs with the designed molecular structures. [ 37,38 ] The PDAs deposited on the specifi c substrates showed the reversible color changes. [ 39,40 ] The results imply that the structures of PDAs have an infl uence on the color-change properties. In our previous work, [ 41 ] the reversible color changes were observed with temperature increase and decrease on the thinfi lm crystals of the layered PDA with intercalation of zinc ion (Zn 2+ ) in the interlayer space. If the structures of the original PDAs are modifi ed by the intercalation, the color-change properties, such as color, responsivity, and reversibility can be tuned by the simple method. Here we focused on the intercalation of metal ions in the layered PDAs for tuning of the structures and the color-change properties. The metal salts of precursor PCDA crystals and their polymerized structures were prepared in the crystalline states and Langmuir-Blodgett

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Structural properties of photochromic polyPCDA: A computational study

Cited by 8 publications

References 32 publications

Modeling the dose dependence of the vis-absorption spectrum of EBT3 GafChromic™ films

Modeling the dose dependence of the vis-absorption spectrum of EBT3 GafChromic™ films

A spectroscopic study of the chromatic properties of GafChromic™EBT3 films

Intercalation‐Induced Tunable Stimuli‐Responsive Color‐Change Properties of Crystalline Organic Layered Compound

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