Preparation and characterization of photochromic poly(methyl methacrylate) and ethyl cellulose nanocapsules containing a spirooxazine dye

Feczkó, Tivadar; Varga, Olívia; Kovács, Margit; Vidóczy, Tamás; Vončina, Bojana

doi:10.1016/j.jphotochem.2011.06.011

Cited by 50 publications

(36 citation statements)

References 26 publications

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“…Furthermore, in our previous studies PVA was found to be a very effective surfactant for emulsifying EC containing organic droplets in the aqueous phase [12][13][14]. Nevertheless, we also examined the usability of other emulsifiers, such as Tween 80, polyvinylpirrolidone and poloxamer (Pluronic F68) beside PMAA.…”

Section: Resultsmentioning

confidence: 99%

“…Torza and Mason [9] described the equilibrium morphology of forming drops as a function of interfacial tensions in the presence of three immiscible liquids. Briefly, if droplets of immiscible liquids (phases 1 and 3) are brought in contact with a third mutually immiscible liquid (phase 2), the final equilibrium morphology can be deduced by determining the various interfacial tensions between the phases (γ 12 , γ 23 , and γ 13 ). The spreading coefficients S i for each phase can be defined as S i = γ jk − (γ ij +γ ik ) (1) and designating phase 1 to be that for which γ 12 > γ 23 , then S 1 < 0.…”

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confidence: 99%

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Microencapsulation of n-hexadecane phase change material by ethyl cellulose polymer

et al. 2014

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Microencapsulation of phase change materials (PCMs) is an attractive opportunity for broadening their applications. In this respect, a novel encapsulating polymer, ethyl cellulose (EC) was used to entrap n-hexadecane (HD) PCM by an emulsion-solvent evaporation method. Emulsifiers strongly influenced the size and morphology of the forming EC-HD composite microcapsules, and they also had a great impact on their thermal properties. All of the three emulsifiers were suitable to prepare quasi core-shell microparticles, though the high porosity of shells resulted in serious leakage in composites prepared by Tween 80, and permeability of particles manufactured by poly(vinyl alcohol) (PVA), as can be stated from scanning electron microscopy and differential scanning calorimetry analysis. Interfacial tension measurements and spreading coefficient analysis enabled the prediction of preparation conditions for usable core-shell microcapsules. Volume weighted mean diameters of the microparticles were 319 m, 92 m and 85 m formed by Tween 80, PVA and poly(methacrylic acid sodium salt) (PMAA), repectively. A significantly higher HD content and latent heat storage capacity could be achieved using PVA and PMAA than with Tween 80. The thermal cycling test indicated good thermal reliability of microcapsules prepared by PMAA, while the energy-storing capacity of composites prepared by PVA decreased substantially, and a dramatic reduction was found in microparticles using Tween 80.

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Section: Resultsmentioning

confidence: 99%

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Microencapsulation of n-hexadecane phase change material by ethyl cellulose polymer

et al. 2014

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“…SO concentration against apparent absorbance at a fixed wavelength in the UV (304nm) is plotted in Figure 2b. Previously [17] we found that the increase of dye concentration resulted …”

Section: Spectral Characteristics Of Uv Source and Photochromic Nanopmentioning

confidence: 89%

“…We found [17] that SO microencapsulation by ethyl cellulose can increase the photochromic half-life by about an order of magnitude, and this lifetime can further increase by a factor of 1.5 with using Tinuvin 144. However, poly(methyl methacrylate)-spirooxazine (PMMA-SO) had a substantially longer lifetime than ethyl cellulose-spirooxazine photochromic nanoparticles when both contained Tinuvin 144; colouration and decolouration of PMMA-SO were several times slower, which is disadvantageous in most of the application.…”

Section: Introductionmentioning

confidence: 88%

Textiles screen‐printed with photochromic ethyl cellulose–spirooxazine composite nanoparticles

Feczkó

Samu

Wenzel

et al. 2012

Coloration Technology

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SummaryPhotochromic compounds change colour due to exposure to light while the reversion may be due either to radiation or may be thermal. The use of photochromism on fabrics can provide new opportunities to develop smart textiles, e.g. sensors and active protective clothes. Ethyl cellulose-1, 3,3,4,5 (and 1,3,3,5,6)]oxazine] composites were prepared by an oil-in-water emulsion, solvent evaporation method in order to form easily suspendable and fatigue resistant photochromic nanoparticles in screen printing paste. Their size was well below 1 m and did not change substantially in a wide range of dye concentration. After screen printing a homogenous photochromic layer was built on a cotton substrate surface, which represented substantial blue colour development in CIELAB colour space measurements due to UV light even at a dye concentration of 0.045 % w/w. The addition of a photodegradation inhibitor, Tinuvin 144 further increased the colouration of the printed fabric.

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“…17 as well as photostabilizer Tinuvin 144 were prepared [44] by using an oilin-water emulsion and following solvent evaporation [45]. These nanoparticles were used for application in a screenprinting paste for textile dying.…”

Section: Polymer Systemsmentioning

confidence: 99%

Nanophotochromism

Barachevsky¹

2015

Organic Photonics and Photovoltaics

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Abstract:The review presents the state-of-the-art analysis of investigations in the field of a new line of research of photochromism -nanophotochromism. The design, properties, and possible applications of photochromic nanoparticles prepared by different methods with the use of photochromic substances (aggregates, host-guest, and polymer systems, solid nanoparticles) as well as core-shell photochromic nanostructures based on polymers, silica, quantum dots, doped upconversion nanocrystals, and Ag, Au, etc. nanoparticles have been reviewed. Keywords: photochromism; photochromic nanoparticles; core-shell photochromic nanoparticles design; photoswitching; aggregates; polymer systems, host-guest systems IntroductionPhotochromism is a very important phenomenon for different applications in photonics. The applications are based on reversible phototransformations of photochromic compounds between two states and changes of their properties that accompany these transformations At present, systems and materials containing photochromic nanopatricles have become highly significant. Among these are nanodimensional particles of photochromic substances, including aggregates, and coreshell systems. As a core, inorganic nanoparticles of gold, silver, metal oxides, quantum dots (QD), and also polymeric nanoparticles are used. The shell consists of photochromic molecules or their aggregates connected to a core surface either chemically or physically. Photochromic nanoparticles with photocontrolled fluorescence arouse a special interest because the fluorescence technique is becoming a leading strategy in biological diagnosis, imaging, and detection applications. This paper is a state-of-the-art review which presents results of studying photochromic nanoparticles including author's own data. The results of earlier research are also surveyed in some other reviews [1][2][3][4][5][6][7][8][9][10][11][12][13]. Photochromic nanoparticles:properties and applications Nanoparticles based on photochromic substances AggregatesThe most known photochromic nanoparticles are aggregates of photochromic organic compounds [14]. These compounds experience reversible photoinduced transformations between two states, Sch. 1A and Sch. 1B. Scheme 1The photoinduced colored merocyanine form B absorbing visible irradiation is formed from a colorless form A as a result of photodissociation of the -C-O-bond of the pyran heterocycle under UV radiation, and this is followed by spontaneous isomerization of the cis-form to the trans one. The colored form B can be converted back to the initial colorless form A upon absorption of visible light or spontaneously during the dark relaxation, which is accelerated by heating.The J-aggregates of nitro-substituted indoline spiropyrans Sch. 2 with long alkyl substituents are of special interest [15].The narrow absorption bands of J-aggregates of these photochromic compounds (Fig. 1) made it possible prepare a specimen of the multilayered optical disk providing freUnauthenticated Download

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Preparation and characterization of photochromic poly(methyl methacrylate) and ethyl cellulose nanocapsules containing a spirooxazine dye

Cited by 50 publications

References 26 publications

Microencapsulation of n-hexadecane phase change material by ethyl cellulose polymer

Microencapsulation of n-hexadecane phase change material by ethyl cellulose polymer

Textiles screen‐printed with photochromic ethyl cellulose–spirooxazine composite nanoparticles

Nanophotochromism

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