Thermochromic Polymers

Seeboth, A.; Lötzsch, D.

doi:10.1002/0471440264.pst510

Cited by 44 publications

(62 citation statements)

References 52 publications

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“…Heat convection in liquids is a limitation, because it makes the thermal lens orientation dependent. Therefore, the thermal lens material should be a solid and polymer-based samples doped with chromophore containing molecules seem to be the best choice, especially thermochromic polymer-based materials [30].…”

Section: Macroscopic Aperture Thermal Lensmentioning

confidence: 99%

Thermal lens in a liquid sample with focal length controllable by bulk temperature

et al. 2016

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In this paper, we propose a new solution, which is an improvement to recent propositions given in [9][10][11]. In contrast to many of the above-cited ideas, which rely on modification of the lens shape, one can induce a refractive index distribution, ∇n, that acts as a lens, without changing the shape of the lensing element. Optical elements with such n distribution, called GRIN (gradient refractive index), are e.g. lenses or fibres, but these elements have ∇n fixed. Therefore, they do not conform to the idea of flexible optical elements (as used e.g. in adaptive optics). Meanwhile, such ∇n can be induced thermally, by irradiation of the thermal lensing element by a heating laser beam, absorbed by this elements material, or by controlled electrical heating of the thermal lensing element [12]. As shown by the authors of Refs. [9][10][11], ∇n formation can lead to the formation of a few millimetre (thus macroscopic)-size aperture thermal lenses whose focal length depends on the heating laser intensity. However, the authors of these two works did not take into account that ∇n at a selected heating laser intensity can depend as well on the bulk temperature of the thermal lens element, irrespective of this element being a liquid [9, 10] or solid [11]. This particular dependence was the subject of our interest, and this work presents the results of our studies.In principle, the laser can also induce the nonlinear Kerr effect or electrostriction force-both of which can lead to nonzero ∇n [13]. In this work, we assume these effects negligible and we focus only on the thermo-optical effect. It follows from nonzero thermo-optical ∂n ∂T parameter of the medium illuminated by heating laser. We present results for a liquid thermal lens material, but thermal lenses can be formed in solids as well, e.g. in glasses. This last case is more attractive from the application point of view. Solids are free from convection and easier to use in different optical set-ups. Additionally, due to the thermal expansion, Abstract An experimental and numerical investigation of the applicability of the temperature-controlled focal length of a thermally induced lens is reported. The thermal lens is formed as a result of absorption of a heating laser beam. Numerical simulations and experimental results show that changing the bulk temperature of the material of the lensing element allows for the selection of its focal length. The range of focal length changes for an example lens is given.

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Section: Macroscopic Aperture Thermal Lensmentioning

confidence: 99%

Thermal lens in a liquid sample with focal length controllable by bulk temperature

et al. 2016

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“…Paraffin, long chain alcohols, alkyl amides and alcanoic acids are solvents typically used. Most solvents contain a long hydrocarbon chain (Kulčar et al, 2010;Bamfield, 2010;Seeboth et al, 2007;Christie & Bryant, 2005;Lee et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…The phenols -bisphenol A (BPA), laurylgallate (LG), ethylgallate (EG) and p-hydroxybenzoic acid methyl ester -are typical developers for reversible thermochromic leuco dye-developer-solvent systems (Seeboth et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Solvents interactions with thermochromic print

Rožić¹,

Vukoje²,

Kapović³

et al. 2017

J. Graph. Eng. Des.

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In this study, the interactions between different solvents (benzene, acetone, cyclohexanone, various alcohols and water) and thermochromic printing ink were investigated. Thermochromic printing ink was printed on metal surface. Components of thermochromic printing inks are polymeric microcapsules and classic yellow offset printing ink. Below its activation temperature, dye and developer within the microcapsules form a blue coloured complex. Therefore, thermochromic print is green. By heating above the activation temperature, blue colour of the complex turns into the leuco dye colourless state and the green colour of the prints turns into the yellow colour of the classic offset pigment. The results of the interaction with various solvents show that the thermochromic print is stable in all tested solvents except in ethanol, acetone and cyclohexanone. In ethanol, the green colour of the print becomes yellow. SEM analysis shows that microcapsules are dissolved. In acetone and cyclohexanone, the green colour of the print turns into blue, and the microcapsules become significantly more visible. Thus, the yellow pigment interacts with examined ketones. Based on the obtained interactions it can be concluded that the microcapsules have more polar nature than the classical pigment particles. Solvent-thermocromic print interactions were analysed using Hansen solubility parameters that rank the solvents based on their estimated interaction capabilities.

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“…in a passive window transparency controlling mechanism [1], battery charge indicator [2] or thermochromic inks [3]. On the other hand, thermochromism finds a wide interest among fundamental researchers, as its principal mechanisms are still not clear and far from being well understood.…”

Section: Introductionmentioning

confidence: 99%