Effect of Crystallinity in Stretched PVA Films on Triplet–Triplet Annihilation Photon Upconversion

Mori, Tomohiro; Mori, Takeshi; Fujii, Akira; Saito, Akane; Saomoto, Hitoshi; Kamada, Kei

doi:10.1021/acsapm.0c00020

Cited by 15 publications

(18 citation statements)

References 31 publications

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“…The crystallinity degradation of the membranes can be explained due to a fast‐drying process occurring during electrospinning, limiting the diffusion, and growth of the polymer chains to form crystals 83 . Moreover, recent research indicates a decrease in the crystallinity of the PVA by stretching it, 84 as could be happening during our spinning process. The formation of hydrogen bonds between the solvent (water) and polymer (PVA) has also been attributed as causing amorphous structures.…”

Section: Resultsmentioning

confidence: 99%

Hydrolyzed collagen on PVA‐based electrospun membranes: Synthesis and characterization

García-Hernández

Morales-Sánchez

Calderón‐Domínguez

et al. 2021

J of Applied Polymer Sci

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Physicochemical, structural, and thermal properties of electrospun membranes depend on process conditions and the type and concentration of the raw materials used to produce them. In this work, the electrospinning technique (ES) is used to synthesize membranes with hydrolyzed collagen (HC) and polyvinyl alcohol (PVA) at two different distances. The characterization of these membranes is then carried out by X-Ray diffraction, Raman spectroscopy, differential scanning calorimetry, water vapor permeability (WVP), microscopy techniques, and porosity measurements. Results show that the morphology of the ES membranes depends mainly on the polymer/solvent system's physicochemical properties and the distance to the collector. Thicker samples (68-86 μm) are formed when using the furthest distance (10 cm), having fiber diameters smaller than 1 μm, porosity percentages up to 90%, and WVP values close to or in the recommended range for wound dressing commercial products. Moreover, the presence of HC results in samples with a less crystalline structure. To the best of our knowledge, this is the first report in which PVA and HC membranes are successfully synthesized by electrospinning and physicochemically characterized.

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Section: Resultsmentioning

confidence: 99%

Hydrolyzed collagen on PVA‐based electrospun membranes: Synthesis and characterization

García-Hernández

Morales-Sánchez

Calderón‐Domínguez

et al. 2021

J of Applied Polymer Sci

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“…In general, as has been reported before, the loss of crystallinity is due to a rapid drying process that occurs during the fiber’s fabrication, since the diffusion and growth of the polymer chains is limited to forming crystals [ 90 , 91 ]. These results are congruent with those reported by Pourhojat et al (2017) [ 3 ] on electrospun PCL membranes, where the higher concentration of Hypericum perforatum the higher crystallinity.…”

Section: Resultsmentioning

confidence: 99%

PVA-Based Electrospun Biomembranes with Hydrolyzed Collagen and Ethanolic Extract of Hypericum perforatum for Potential Use as Wound Dressing: Fabrication and Characterization

et al. 2022

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Biological, physicochemical, structural, and thermal properties of PVA-based electrospun wound dressings added with hydrolyzed collagen (HC) and different concentrations of Hypericum perforatum ethanolic extract (EEHP) were studied. Membrane characterization was carried out by X-ray diffraction, Fourier infrared spectroscopy, differential scanning calorimetry, barrier properties, scanning electron microscopy, image analysis (diameter and pore size), as well as antimicrobial and anti-inflammatory activities. Results showed that the PVA/HC/EEHP materials, fabricated under controlled conditions of temperature and humidity, generated fiber membranes with diameters between 140–390 nm, adequate porosity and pore size for cell growth (67–90% and 4–16 µm, respectively), and good barrier properties (0.005–0.032 g·m−2 s−1) to be used in the treatment of conditions on the skin, and was even better than some commercial products. Finally, they showed to have anti-inflammatory (>80%), and antimicrobial activity against S. aureus and S. Epiderm. Furthermore, higher crystalline structure was observed according to the EEHP concentration. In addition, this is the first report in which PVA/HC/EEHP membranes are successfully fabricated and characterized.

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“…These results clearly show that IUC is governed by concentration of the triplet species with the 3 DPA* moiety, not by the prepared concentration of the ground state DPA. Employment of Kamada fitting function shown in eqn 5, [35][36][37] !" = #$ $1 +…”

Section: Resultsmentioning

confidence: 99%

Elongation of Triplet Lifetime Caused by Intramolecular Energy Hopping in Diphenylanthracene Dyads Oriented to Undergo Efficient Triplet–Triplet Annihilation Upconversion

et al. 2021

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Triplet-triplet annihilation (TTA)-assisted photon upconversion (TTA-UC) in three dyads (DPA-Cn-DPA), comprised of two diphenylanthracene (DPA) moieties connected by nonconjugated C1, C2, and C3 linkages (Cn), has been investigated. The performance of these dyads as energy acceptors in the presence of the energy donor platinum octaethylporphyrin are characterized by longer triplet lifetimes (tT) and different TTA rate constants than those of the parent DPA. The larger tT of the linked systems, caused by "Intramolecular Energy Hopping" in the triplet dyad 3 DPA*-Cn-DPA, results in a low threshold intensity, a key characteristic of efficient TTA-UC.

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Effect of Crystallinity in Stretched PVA Films on Triplet–Triplet Annihilation Photon Upconversion

Cited by 15 publications

References 31 publications

Hydrolyzed collagen on PVA‐based electrospun membranes: Synthesis and characterization

Hydrolyzed collagen on PVA‐based electrospun membranes: Synthesis and characterization

PVA-Based Electrospun Biomembranes with Hydrolyzed Collagen and Ethanolic Extract of Hypericum perforatum for Potential Use as Wound Dressing: Fabrication and Characterization

Elongation of Triplet Lifetime Caused by Intramolecular Energy Hopping in Diphenylanthracene Dyads Oriented to Undergo Efficient Triplet–Triplet Annihilation Upconversion

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