Photoinduced thermochromic or thermoluminescent compositions

Abstract

The present invention relates to a photo-induced thermochromic or thermoluminescent composition comprising: a) nanoparticles, in particular metallic gold nanoparticles, capable of absorbing near infrared (NIR) radiation and converting said NIR radiation into heat; b) one or more phase change materials (PCMs) selected from: b1) PCMs capable of acting as thermochromic or fluorescence thermochromic promoters; and b2) PCMs incapable of acting as thermochromic or fluorescence thermochromic promoters; c) one or more dyes selected from: c1) dyes capable of changing their color or luminescence properties when said PCMs change between solid and liquid state; and c2) dyes incapable of changing their color or luminescence properties when said PCMs change between solid and liquid state; and articles containing said composition. The present invention also relates to their methods of preparation and their use in therapy, cosmetics, diagnostics, optical devices and anti-counterfeiting techniques.

Description

TECHNICAL FIELD

[0001] This application claims the benefit of European Patent Application EP 19383086.6, filed on December 5, 2019.

[0002] The present invention relates to photoactive functional materials. In particular, the present invention relates to photoinduced thermochromic or thermoluminescent compositions containing nanoparticles, phase change materials (PCMs) and dyes, and articles containing said compositions. The present invention also relates to their methods of preparation and their use in therapy, cosmetics, diagnostics and optical devices. BACKGROUND

[0003] Photoactive functional materials, in particular photoresponsive chromic and luminescent materials, are smart systems able to respond to light stimuli. It has been proposed to apply these materials in a large variety of different fields, such as in particular optical devices, electronics, medicine and imaging, among others. A key component of these smart materials is the photochromic unit, which is usually composed of photoisomerizable organic compounds (e.g. azobenzenes, spiropyrans, etc.) able to interconvert between different states with different absorption and / or luminescence spectra. Thus, if the absorption / luminescence properties of one of the two states (isomers) are different, their color and / or fluorescence changes upon light irradiation. Alternatively, photochromes can be coupled to non-photoisomerizable fluorophores to achieve luminescence modulation in one of the two isomeric forms of the photochrome through engineered interchromophoric interactions (e.g. photoinduced energy or electron transfer). In either case, a molecular light switch is required to obtain a light-controlled switch material.

[0004] Recently, a large amount of research is being undertaken to shift the photoresponse of fluorescent modulation units from the high-energy UV to the harmless visible and near-infrared (NIR) spectral regions. NIR-responsive light-controlled switch dyes not only allow improving their basic material functionalities (e.g. resistance to fatigue or inhibition of final destructive readout), but also are relevant to biomedical applications (i.e. less tissue photodamage, deeper light penetration in biological environments) or solar-related applications (exploitation of the NIR part of the daylight radiation). Currently, NIR-responsive switch materials are achieved by i) direct (although not straightforward) molecular design and synthesis of the light switch that absorbs at lower frequencies, ii) multiphoton absorption of the dye or switch sensitizer, or iii) use of NIR-absorbing (photoinduced electron transfer, triplet, singlet) sensitizers or upconverting nanoparticles.

[0005] However, while smart materials based on photochromes have the intrinsic advantage of using light as an external stimulus, a remote, non-invasive stimulus with precise temporal and spatial control, these materials have some drawbacks, especially those developed to be active in the NIR region. The drawbacks of the above-mentioned strategies are listed as follows:

[0006] - they remain complex and time-consuming to synthesize and / or require high excitation power densities to activate the switching units.

[0007] - they involve directly or sensitized isomerizable molecules (cis-trans or open ring / closed ring reactions), limiting the choice of color / fluorescence modulators to specific types of molecules (e.g. spiropyrans, chromenes, azobenzenes, diarylethene, etc.). This is even more apparent if long wavelength responsive systems (e.g. NIR) are required, while the availability of commercialized photochromic pigments is rather limited.

[0008] - their photoinduced operation is far from being optimal, as they often present limited photoisomerization probabilities and / or efficiencies (low quantum yields).

[0009] - under continuous irradiation (direct excitation), non-negligible photodegradation effects can be induced, especially when harmful UV radiation is used.

[0010] - when used in the solid state or dispersed in a solid matrix, additional detrimental effects on the photoinduced behavior of the photochromic pigments are usually observed (e.g. matrix effects that inhibit the photochromic performance) with respect to solutions.

[0011] - since light is required both for changing and monitoring the state of the system, undesired photochromic interconversions can occur when measuring the color and / or luminescence of the material, which can become a serious limitation for certain applications (i.e. destructive readout).

[0012] Therefore, from what is known in the art, there is still a need to provide improved methods for preparing NIR light-switchable color-changing and luminescent materials. SUMMARY

[0013] The inventors of the present application have surprisingly provided highly efficient light-switchable materials by a photoinduced thermochromic or thermoluminescent composition. Specifically, the inventors have found that the compositions of the present application show higher absorbance, photostability and spectral tunability compared to the compositions disclosed in the state of the art. These compositions comprise: nanoparticles, in particular metallic gold nanoparticles, capable of absorbing NIR radiation and converting said NIR radiation into heat; one or more PCMs; and one or more dyes.

[0014] In particular, the inventors have found that the use of a combination of nanoparticles, in particular metallic gold nanoparticles, capable of absorbing NIR radiation and converting the near infrared radiation into heat, and a PCM allows to promote the phase change (from solid to liquid) of said PCM after the excitation of the photo-induced thermochromic or thermoluminescent composition of the application with low energy (i.e. NIR) and low power density radiation. This phase change (i.e. melting / solidification) of the PCM of the application modifies the absorption / emission properties of the dye, thus generating a change in its color or luminescence.

[0015] Moreover, the photo-induced thermochromic or thermoluminescent composition of the application is also advantageous because of the use of low energy radiation (i.e. NIR) and the activation of the nanoparticles, in particular metallic gold nanoparticles, at wavelengths in the NIR range, which avoids the unwanted photochemical processes disclosed in the prior art related to the use of high energy radiation (i.e. harmful UV) which induces the direct photoexcitation of the photochromic dye. Therefore, the use of low energy radiation guarantees an increase in the service life of these materials due to the prevention of the degradation of the composition components.

[0016] The behavior of the dye (both the thermochromic and / or luminescent compound) included in the photo-induced thermochromic or thermoluminescent composition of the application can be modulated by varying the type and / or concentration of the dye, the PCM, the nanoparticles, the excitation power density and / or the presence of additional thermochromic or fluorescent thermochromic promoters. For the purposes of the present application, the behavior of the dye refers to the type of color / luminescence, the kinetic response and / or the color / luminescence intensity.

[0017] The composition of the application also has a low content of NIR-absorbing nanoparticles, in particular metallic nanoparticles, and a homogeneous distribution of said NIR-absorbing nanoparticles. This is advantageous because it does not affect the final color of the material and allows maintaining the uniformity and intensity of the color or luminescence change in all the compositions.

[0018] In summary, the advantages of the photo-induced thermochromic or thermoluminescent composition of the application can be related to the combination of the components of said composition and the use of nanoparticles, in particular metallic gold nanoparticles, as a trigger of the color / luminescence change. These advantages are listed below:

[0019] - the preparation of adjustable nanoparticles, in particular metallic gold nanoparticles, capable of absorbing NIR radiation and converting said NIR radiation into heat, and of the photo-induced thermochromic or thermoluminescent compositions containing them, as a triggering unit, is easier compared to the preparation of NIR-absorbing molecular dyes and compositions containing them.

[0020] - The nanoparticles, in particular metallic gold nanoparticles, present in the composition of the application, able to absorb NIR radiation and to convert said NIR radiation into heat, benefit from a higher absorption rate, photostability, photothermal efficiency and easier spectral tunability compared to organic dyes, allowing the use of low power NIR radiation to trigger the change of state of the PCM from solid to liquid (melting).

[0021] - The composition of the application avoids direct or sensitized photoisomerization for absorption / emission modulation, avoids typical problems associated with photochromic pigments such as low photoisomerization quantum yield, photodegradation, destructive readout or complex design of energy / electron transfer schemes, and permits the use of a wider variety of dyes to build color or luminescence optical switches.

[0022] - The decoupling of the triggering unit from the color / luminescence change dye (by absorption in NIR) allows the use of UV filters in the final application, thus ensuring a higher protection and lower fatigue resistance (more durable material) of the dye.

[0023] - Contrary to what happens with standard T-type photochromic materials falling outside the scope of the present application and disclosed in the prior art, the higher the temperature the more favorable to the photoactivated state when using the composition of the application. This cannot be achieved with standard T-type photochromic materials whose equilibrium migrates towards the non-photoactivated state as the temperature increases.

[0024] Thus, the photoinduced thermochromic or thermoluminescent composition of the application has several advantages compared to the prior art, as demonstrated in the experimental data disclosed in the examples. Mainly, they have an adjustable, fast, clear optical response and strong color and / or luminescence change.

[0025] Thus, a first aspect of the application relates to a light-induced thermochromic or thermoluminescent composition comprising: a) nanoparticles capable of absorbing near infrared radiation (NIR) and converting said NIR radiation into heat; b) one or more phase change materials (PCMs) selected from: bl) PCMs capable of acting as a thermochromic or fluorochromic promoter; and b2) PCMs incapable of acting as a thermochromic or fluorochromic promoter; c) one or more dyes selected from: cl) dyes capable of changing their color or luminescence properties when said PCMs change between a solid state and a liquid state; and c2) dyes incapable of changing their color or luminescence properties when said PCMs change between a solid state and a liquid state; wherein: - when said PCMs are incapable of acting as a thermochromic or fluorochromic promoter (b2), and said dyes are incapable of changing their color or luminescence properties when said PCMs change between a solid state and a liquid state (c2), said light-induced thermochromic or thermoluminescent composition further comprises one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; or when at least said PCMs are capable of acting as a thermochromic or fluorochromic promoter (bl) or said dyes are capable of changing their color or luminescence properties when said PCMs change between a solid state and a liquid state (cl), said light-induced thermochromic or thermoluminescent composition optionally comprises (d) one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; wherein said nanoparticles (a) are metallic gold nanoparticles capable of absorbing near infrared radiation (NIR) and converting said NIR radiation into heat.

[0026] A second aspect of the application relates to a light-induced thermochromic or thermoluminescent self-supporting film comprising the light-induced thermochromic or thermoluminescent composition as defined in the first aspect of the application, one or more polymers and optionally one or more excipients.

[0027] A third aspect of the application relates to a light-induced thermochromic or thermoluminescent article comprising the composition as defined in the first aspect of the application or the self-supporting film as defined in the second aspect of the application.

[0028] A fourth aspect of the present application relates to the use of: a light-induced thermochromic or thermoluminescent composition comprising: a) nanoparticles, in particular metallic gold nanoparticles, capable of absorbing near-infrared radiation (NIR) and converting said NIR radiation into heat; b) one or more phase change materials (PCMs) selected from: bl) PCMs capable of acting as thermochromic or fluorochromic promoters; and b2) PCMs incapable of acting as thermochromic or fluorochromic promoters; c) one or more dyes selected from: cl) dyes capable of changing their color or luminescence properties when said PCMs change between solid and liquid state; and; c2) dyes incapable of changing their color or luminescence properties when said PCMs change between solid and liquid state; in an optical device; wherein: - when said PCMs are incapable of acting as thermochromic or fluorochromic promoters (b2), and said dyes are incapable of changing their color or luminescence properties when said PCMs change between solid and liquid state (c2), said light-induced thermochromic or thermoluminescent composition further comprises one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; or when at least said PCMs are capable of acting as thermochromic or fluorochromic promoters (bl) or said dyes are capable of changing their color or luminescence properties when said PCMs change between solid and liquid state (cl), said light-induced thermochromic or thermoluminescent composition optionally comprises (d) one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; or a light-induced thermochromic or thermoluminescent self-supporting film comprising said light-induced thermochromic or thermoluminescent composition, one or more polymers and optionally one or more excipients; or a light-induced thermochromic or thermoluminescent article comprising said light-induced thermochromic or thermoluminescent composition or self-supporting film.

[0029] A fifth aspect of the present application relates to the use of: a light-induced thermochromic or thermoluminescent composition comprising: a) nanoparticles, in particular metallic gold nanoparticles, capable of absorbing near infrared radiation (NIR) and converting said NIR radiation into heat; b) one or more phase change materials (PCM) selected from: bl) PCMs capable of acting as chromic or fluorochromic promoters; and b2) PCMs not capable of acting as chromic or fluorochromic promoters; c) one or more dyes selected from: cl) dyes capable of changing their color or luminescence properties when said PCMs change between solid and liquid state; and; c2) dyes not capable of changing their color or luminescence properties when said PCMs change between solid and liquid state; in anti-counterfeiting techniques; or a light-induced thermochromic or thermoluminescent self-supporting film comprising said light-induced thermochromic or thermoluminescent composition, one or more polymers and optionally one or more excipients; or a light-induced thermochromic or thermoluminescent article comprising said light-induced thermochromic or thermoluminescent composition or self-supporting film. DETAILED DESCRIPTION

[0030] All terms used in the present application, unless otherwise expressed, are to be interpreted in their commonly used meaning known in the art. Other more specific terms used in the present application are described below and are intended to be uniformly applied throughout the specification and claims, unless a definition explicitly provided is broader than the commonly used definition.

[0031] For the purposes of the present application, all given ranges are inclusive of the lower and upper endpoints of the range. Unless specifically stated, ranges given, for example, temperatures, times, weights, etc., are to be considered approximate values.

[0032] As mentioned above, the present application relates to a photo-induced thermochromic or thermoluminescent composition. The term "photo-induced" refers to the fact that the effect is induced by the action of light. For the purposes of the present application, the change in color or luminescence is induced by the irradiation of light, in particular NIR radiation. The term "thermochromic" refers to a composition which changes or is capable of changing its color (hue) in response to temperature fluctuations. Thus, for the purposes of the present application, a "photo-induced thermochromic" composition refers to a composition which changes or is capable of changing its absorption spectrum (color) by temperature fluctuations promoted by irradiation, in particular NIR irradiation. Furthermore, the term "thermoluminescent" refers to a composition which changes or is capable of changing its luminescence capacity in response to temperature fluctuations. Thus, for the purposes of the present application, a "photo-induced thermoluminescent" composition refers to a composition which changes or is capable of changing its luminescence by temperature fluctuations promoted by irradiation, in particular NIR irradiation.

[0033] In one embodiment, the photo-induced thermochromic or thermoluminescent composition is selected from:

[0034] a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat, in particular metallic gold nanoparticles;

[0035] b) one or more PCMs (b1 ) capable of acting as a chromic or fluorochromic promoter in its solid and / or liquid state;

[0036] c) one or more dyes (c2) which are not capable of changing their color or luminescence properties when the PCM changes between solid and liquid state; and

[0037] optionally d) one or more chromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators;

[0038] a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat, in particular metallic gold nanoparticles;

[0039] b) one or more PCMs (b2) which are not capable of acting as a chromic or fluorochromic promoter in its solid and / or liquid state;

[0040] c) one or more dyes (c1 ) which are capable of changing their color or luminescence properties when the PCM changes between solid and liquid state; and

[0041] optionally d) one or more chromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators;

[0042] a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat, in particular metallic gold nanoparticles;

[0043] b) one or more PCMs (bl) capable of acting as a color- or fluorescence- change promoter in its solid and / or liquid state;

[0044] c) one or more dyes (cl) capable of changing its color or luminescence properties when the PCM changes between solid and liquid state; and

[0045] optionally d) one or more color- or fluorescence- change promoters selected from color developers, luminescence quenchers and luminescence activators;

[0046] and

[0047] a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat, in particular metallic gold nanoparticles;

[0048] b) one or more PCMs (b2) incapable of acting as a color- or fluorescence- change promoter in its solid and / or liquid state;

[0049] c) one or more dyes (c2) incapable of changing its color or luminescence properties when the PCM changes between solid and liquid state; and

[0050] d) one or more color- or fluorescence- change promoters selected from color developers, luminescence quenchers and luminescence activators.

[0051] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application comprises:

[0052] a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat, in particular metallic gold nanoparticles;

[0053] b) one or more PCMs (bl) capable of acting as a color- or fluorescence- change promoter in its solid and / or liquid state;

[0054] c) one or more dyes (cl) capable of changing its color or luminescence properties when the PCM changes between solid and liquid state; and

[0055] optionally d) one or more color- or fluorescence- change promoters selected from color developers, luminescence quenchers and luminescence activators.

[0056] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application comprises:

[0057] a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat, in particular metallic gold nanoparticles;

[0058] b) one or more PCMs (b2) incapable of acting as a color- or fluorescence- change promoter in its solid and / or liquid state;

[0059] c) one or more dyes (c1) capable of changing their color or luminescence properties when the PCM changes between the solid and the liquid state; and

[0060] Optionally d) one or more color or fluorescence coloration promoters selected from color developers, luminescence quenchers and luminescence activators.

[0061] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application comprises:

[0062] a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat, in particular metallic gold nanoparticles;

[0063] b) one or more PCMs (b1) capable of acting as color or fluorescence coloration promoters in their solid and / or liquid state;

[0064] c) one or more dyes (c1) capable of changing their color or luminescence properties when the PCM changes between the solid and the liquid state; and

[0065] Optionally d) one or more color or fluorescence coloration promoters selected from color developers, luminescence quenchers and luminescence activators.

[0066] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application comprises:

[0067] a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat, in particular metallic gold nanoparticles;

[0068] b) one or more PCMs (b2) incapable of acting as color or fluorescence coloration promoters in their solid and / or liquid state;

[0069] c) one or more dyes (c2) incapable of changing their color or luminescence properties when the PCM changes between the solid and the liquid state; and

[0070] d) one or more color or fluorescence coloration promoters selected from color developers, luminescence quenchers and luminescence activators.

[0071] Material composition

[0072] Nanoparticles

[0073] The composition of the application comprises nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat, in particular metallic gold nanoparticles. As disclosed hereinabove, these nanoparticles are capable of absorbing NIR radiation and converting near infrared radiation into heat energy (heat), which allows the PCM to change from the solid to the liquid state.

[0074] For the purposes of the present invention, the nanoparticles capable of absorbing NIR radiation and converting it into heat absorb NIR radiation having a wavelength of 600 nm to 2200 nm. In one embodiment, the nanoparticles capable of absorbing NIR radiation and converting it into heat absorb NIR radiation having a wavelength of 650 nm to 1600 nm. In one embodiment, the nanoparticles capable of absorbing NIR radiation and converting it into heat absorb NIR radiation having a wavelength of 700 nm to 1200 nm. In one embodiment, the nanoparticles capable of absorbing NIR radiation and converting it into heat absorb NIR radiation having a wavelength of 700 nm to 900 nm. In a particular embodiment, the nanoparticles capable of absorbing NIR radiation and converting it into heat absorb NIR radiation having a wavelength of 830 nm.

[0075] In one embodiment, the nanoparticles capable of absorbing NIR radiation and converting it into heat are non-metallic nanoparticles capable of absorbing NIR radiation and converting it into heat.

[0076] In one embodiment, the nanoparticles capable of absorbing NIR radiation and converting it into heat are metallic nanoparticles (MP) capable of absorbing NIR radiation and converting it into heat. For the purposes of the present invention, the terms "metallic nanoparticles capable of absorbing NIR radiation and converting it into heat", "NIR-absorbing metallic nanoparticles" and "NIR-absorbing MP" have the same meaning and are used interchangeably. The acronym "MP" denotes metallic nanoparticles.

[0077] The presence of NIR-absorbing MPs, in particular metallic gold nanoparticles, in the compositions of the present invention is advantageous because it allows:

[0078] - minimization or elimination of the color contribution of the MPs to the material in which they are incorporated,

[0079] - selective irradiation of the MPs in the NIR prevents their photodegradation without exciting the dyes,

[0080] - use of low-energy radiation, which does not have a deleterious effect on the material or the substrate,

[0081] - high photothermal efficiency by irradiation with NIR radiation without using large amounts of MPs,

[0082] - use of highly penetrating radiation (not absorbed by other material components), which enables activation of the chromogenic / luminescent switch in deeper parts of the material or in deeper biological tissues.

[0083] In one embodiment, the composition comprises NIR-absorbing MP having a particle size of 5 to 500 nm. In one embodiment, the composition comprises NIR-absorbing MP having a particle size of 5 to 100 nm. The composition comprises NIR-absorbing MP having a particle size of 50 to 90 nm. The term "particle size" refers to the size of the particle measured in nm. The measurement is performed using a suitable device by conventional analytical techniques, for example, microscopy determination using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). In the present application, the particle size is measured by dynamic light scattering (DLS, z-sizer) technique. The data is then analyzed using a general model assuming a spherical shape of the particle to calculate the size of the particle that produces the scattering pattern. The terms "particle size distribution" or "PSD" have the same meaning and are used interchangeably. They refer to the size distribution of the particles prepared.

[0084] In one embodiment, the composition of the present application comprises NIR-absorbing MP wherein the metal is selected from the group consisting of gold, platinum, silver, palladium, rhodium, osmium, ruthenium, rhodium, rhenium, molybdenum, copper, iron, nickel, tin, beryllium, cobalt, antimony, chromium, manganese, zirconium, tin, zinc, tungsten, titanium, vanadium, lanthanum, cerium, alloys thereof, oxides thereof and mixtures thereof. In one embodiment, the composition of the present application comprises NIR-absorbing MP wherein the metal is selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, alloys thereof, oxides thereof and mixtures thereof. In one embodiment, the composition of the present application comprises NIR-absorbing MP wherein the metal is selected from the group consisting of gold, platinum, silver, palladium, rhodium, osmium, ruthenium, rhodium, rhenium, molybdenum, iron, nickel, tin, beryllium, cobalt, antimony, chromium, manganese, zirconium, tin, zinc, tungsten, titanium, vanadium, lanthanum, cerium, alloys thereof, oxides thereof and mixtures thereof. In one embodiment, the composition of the present application comprises NIR-absorbing MP wherein the metal is selected from the group consisting of gold, platinum, palladium, silver, aluminum, alloys thereof, oxides thereof and mixtures thereof. In a particular embodiment, the composition of the present application comprises NIR-absorbing MP wherein the metal is gold, oxides thereof and mixtures thereof. In a particular embodiment, the composition of the present application comprises NIR-absorbing MP wherein the metal is silver, oxides thereof and mixtures thereof.

[0085] As used herein, the term "nanoparticle" refers to a particle having dimensions on the nanometer scale, i.e. having a diameter of from 5 to 500 nm, and having any size, shape or morphology. As used herein, the term nanoparticle can include spherical nanoparticles as well as non-spherical nanoparticles. In one embodiment, the composition of the present application comprises NIR-absorbing nanoparticles in a form selected from the group consisting of nanospheres, nanostars, nanodumbells, nanotubes, nanoshells, nanorods, nanocages, nanohemispheres, nanodomes and nanopyramids. In one embodiment, the composition of the present application comprises NIR-absorbing nanoparticles in a form selected from the group consisting of nanospheres, nanoshells and nanorods. In one embodiment, the composition of the present application comprises NIR-absorbing nanoparticles in the form of nanoshells.

[0086] The term "nanoshell" is a type of nanoparticle characterized by a discrete core-shell structure, wherein the shell surrounds at least a portion of the core. The core of a nanoshell can be hollow (i.e. empty or filled with a gas) or filled with a liquid (water, oil, etc.) or solid (i.e. polymer) different from the shell.

[0087] The term "nanosphere" refers to a type of nanoparticle characterized by a solid structure having a spherical or quasi-spherical shape.

[0088] The term "nanorod" refers to a type of nanoparticle characterized by a solid structure and an anisotropic rod-like shape, having a longitudinal axis and a transversal axis of different lengths.

[0089] In one embodiment, the composition of the present application is a composition wherein the NIR-absorbing MP is a gold nanoshell.

[0090] In one embodiment, the composition of the present application comprises NIR-absorbing MPs in an amount of from 0.00005 mg to 0.5 mg / mg of PCM, in particular from 0.00024 mg to 0.15 mg / mg of PCM. Thus, the composition of the present application comprises a low content of nanoparticles, which is advantageous as it allows reducing the cost of the final material and minimizing or eliminating the optical changes of the material containing said MPs due to the color of the NIR-absorbing MPs.

[0091] PCM

[0092] The composition of the present application comprises one or more phase change materials (hereinafter PCM). As mentioned above, a PCM is a substance that exhibits a high latent heat of fusion, storing and releasing large amounts of energy upon melting and solidification, respectively. For the purposes of the present application, the term "PCM" refers to a material that is able to change from a solid state to a liquid state upon absorption of heat and to change from a liquid state to a solid state upon release of heat.

[0093] The composition of the present application comprises one or more PCMs (b) selected from b1) PCMs capable of acting as color change or fluorescence color change accelerators and b2) PCMs incapable of acting as color change or fluorescence color change accelerators.

[0094] In one embodiment, the composition comprises one or more PCMs (b1) capable of acting as color change or fluorescence color change accelerators. The term "capable of acting as color change or fluorescence color change accelerators" refers to compounds that can induce a change in color and / or luminescence properties (position and intensity of the absorption / luminescence band), modulate the speed of the change in color or luminescence properties. In one embodiment, the composition comprises one or more PCMs (b1) capable of acting as color change or fluorescence color change accelerators. In one embodiment, the composition comprises one or more PCMs (b1) capable of acting as color change or fluorescence color change accelerators, in addition to alkanes-containing PCMs, alkenes-containing PCMs and alkynes-containing PCMs. In one embodiment, the composition comprises one or more PCMs (b1) capable of acting as color change or fluorescence color change accelerators, selected from acid- containing compounds, amine-containing compounds, sulfur-containing compounds, alcohol- containing compounds and mixtures thereof. In one embodiment, the composition comprises one or more PCMs (b1) capable of acting as color change or fluorescence color change accelerators, selected from: acid-containing compounds, amine-containing compounds, sulfur-containing compounds selected from thiol-containing compounds, sulfuric acid-containing compounds, sulfonic acid-containing compounds and mixtures thereof, alcohol-containing compounds, and mixtures thereof.

[0095] In one embodiment, the composition comprises one or more PCMs (b1) capable of acting as color change or fluorescence color change accelerators, selected from (C1-C 30 )-alkyl-COOH, (C1-C 30 )-alkyl-COO(C1-C 30 )alkyl, (C1-C 30 )-alkyl-OH, (C1-C 30 )-alkyl-O-(C1-C 30 )alkyl, (C1-C 20 )-alkyl-NH2, (C1-C 20 )-alkyl-NH((C1-C 20 )alkyl)2, (C1-C 20 )-alkyl-N((C1-C 20 )alkyl)3, (C1-C 20 )-alkyl-NH-CO-(C1-C 20 )-alkyl, (C1-C 20 )-alkyl-N(CO-(C1-C 20 )-alkyl)2, (C2-C 30 )-alkenyl-COOH, (C2-C 30)-alkenyl-COOH, (C2-C 30 )alkenyl, (C2-C 30 )-alkenyl-OH, (C2-C 30 )-alkenyl-O-(C2-C 30 )alkenyl, (C2-C 20 )-alkenyl-NH2, (C2-C 20 )-alkenyl-NH((C2-C 20 )alkenyl)2, (C2-C 20 )-alkenyl-N((C2-C 20 )alkenyl)3, (C2-C 20 )-alkenyl-NH-CO-(C2-C 20 )-alkenyl, (C2-C 20 )-alkenyl-N(CO-(C2-C 20 )-alkenyl)2, (C1-C 30 )-alkyl-O-(C2-C 30 )alkenyl, (C2-C 30 )-alkenyl-O-(C1-C 30 )alkyl, (C1-C 20 )-alkyl-NH-CO-(C2-C 20 )-alkenyl, (C2-C 20 )-alkenyl-NH-CO-(C1-C 20 )-alkyl, (C1-C 20 )-alkyl-N(CO-(C2-C 20 )-alkenyl)2, (C2-C 20 )-alkenyl-N(CO-(C1-C 20 )-alkyl)2, C2-C 30 )-alkynyl-COOH, (C2-C 30 )-alkynyl-COO(C2-C 30 )alkynyl, (C2-C 30 )-alkynyl-OH, (C2-C 30 )-alkynyl-O-(C2-C 30 )-alkynyl, (C2-C 20 )-alkynyl-NH2, (C2-C 20 )-alkynyl-NH((C2-C 20 )alkynyl)2, (C2-C 20 )-alkynyl-N((C2-C 20 )alkynyl)3, (C2-C 20 )-alkynyl-NH-CO-(C2-C 20 )-alkynyl, (C2-C 20 )-alkynyl-N(CO-(C2-C20 )-Alkyne)2, (C1-C 30 )-alkyl-O-(C2-C 30 )-Alkyne group, (C2-C 30 )-Alkyne-O-(C1-C 30 )-alkyl, (C5-C 20 )-alkyl-NH-CO-(C2-C 20 )-Alkyne group, (C2-C 20 )-Alkyne-NH-CO-(C1-C 20 )-alkyl, (C1-C 20 )-alkyl-N(CO-(C2-C 20 )-Alynyl)2, (C2-C 20 )-Alkyne-N(CO-(C1-C 20 )-alkyl)2, triglycerides and their isomers.

[0096] In one embodiment, the composition comprises one or more PCM(b1) capable of acting as a color-changing or fluorescence-changing promoter, selected from (C4-C5) 30 )-alkyl-COOH, (C1-C 30 )-alkyl-COO(C1-C 30 )alkyl, (C8-C 30 )-alkyl-OH, (C1-C 30 )-alkyl-O-(C1-C 30 )alkyl, (C5-C 20 )-alkyl-NH2, (C1-C 20 )-alkyl-NH((C1-C 20 )alkyl)2、(C1-C 20 )-alkyl-N((C1-C 20 )alkyl)3, (C5-C 20 )-alkyl-NH-CO-(C1-C 20 )-alkyl, (C1-C 20 )-alkyl-N(CO-(C1-C 20 )-alkyl)2, (C4-C 30 )-Alkenyl-COOH, (C2-C 30 )-Alkenyl-COO(C2-C 30 )alkenyl, (C8-C 30 )-Alkenyl-OH, (C2-C 30 )-Alkenyl-O-(C2-C 30 )alkenyl, (C5-C 20 )-Alkenyl-NH2, (C2-C 20 )-Alkenyl-NH((C2-C20 )alkenyl, (C2-C 20 )-alkenyl-N((C2-C 20 )alkenyl)2, (C5-C 20 )-alkenyl-NH-CO-(C2-C 20 )-alkenyl, (C2-C 20 )-alkenyl-N(CO-(C2-C 20 )-alkenyl)2, (C1-C 30 )-alkyl-O-(C2-C 30 )alkenyl, (C2-C 30 )-alkenyl-O-(C1-C 30 )alkyl, (C5-C 20 )-alkyl-NH-CO-(C2-C 20 )-alkenyl, (C5-C 20 )-alkenyl-NH-CO-(C1-C 20 )-alkyl, (C1-C 20 )-alkyl-N(CO-(C2-C 20 )-alkenyl)2, (C2-C 20 )-alkenyl-N(CO-(C1-C 20 )-alkyl)2, C4-C 30 )-alkynyl-COOH, (C2-C 30 )-alkynyl-COO(C2-C 30 )alkynyl, (C8-C 30 )-alkynyl-OH, (C2-C 30 )-alkynyl-O-(C2-C 30 )alkynyl, (C5-C 20 )-alkynyl-NH2, (C2-C 20 )-alkynyl-NH((C2-C 20 )alkynyl)2, (C2-C 20 )-alkynyl-N((C2-C 20 )alkynyl)3, (C5-C 20 )-alkynyl-NH-CO-(C2-C 20 )-alkynyl, (C2-C 20 )-alkynyl-N(CO-(C2-C 20 )-alkynyl)2, (C1-C 30 )-alkyl-O-(C2-C 30 )-alkynyl, (C2-C 30 )-alkynyl-O-(C1-C 30 )-alkyl, (C5-C 20 )-alkyl-NH-CO-(C2-C 20 )-alkynyl, (C5-C)alkyl, (C1-C 20 )alkyl-NH-CO-(C1-C 20 )alkyl, (C1-C 20 )alkyl-N(CO-(C2-C 20 )alkyl)2, (C2-C 20 )alkyl-N(CO-(C1-C 20 )alkyl)2, triglycerides and isomers thereof.

[0097] In one embodiment, the composition of the application is a composition wherein the one or more PCMs (b1) capable of acting as a color change or fluorescence color change promoter is selected from the group consisting of (C4-C 30 )alkyl-COOH and isomers thereof. In one embodiment, the composition of the application is a composition wherein the one or more PCMs (b1) capable of acting as a color change or fluorescence color change promoter is selected from the group consisting of dodecanoic acid, stearic acid and mixtures thereof. In one embodiment, the composition of the application is a composition wherein the one or more PCMs (b1) capable of acting as a color change or fluorescence color change promoter is selected from the group consisting of (C1-C 30 )alkyl-COO(C1-C 30 )alkyl, methyl palmitate, methyl stearate and methyl arachidate and isomers thereof. In one embodiment, the composition of the application is a composition wherein the one or more PCMs (b1) capable of acting as a color change or fluorescence color change promoter is (C8-C 30 )alkyl-OH. The term "alkyl-OH" refers to a saturated branched or straight chain hydrocarbon containing the number of carbon atoms specified in the description or claims, wherein at least one hydrogen atom is replaced by a hydroxyl group. In one embodiment, the composition of the application is a composition wherein the one or more PCMs (b1) capable of acting as a color change or fluorescence color change promoter is selected from the group consisting of (C8-C 30 )alkyl-OH and isomers thereof, such as 1-tetradecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol or mixtures thereof. In one embodiment, the composition of the application is a composition wherein the one or more PCMs (b1) capable of acting as a color change or fluorescence color change promoter is selected from the group consisting of (C8-C 30 )alkyl-OH, such as 1-tetradecanol, 1-hexadecanol or mixtures thereof. In one embodiment, the composition of the application is a composition wherein the one or more PCMs (b1) capable of acting as a color change or fluorescence color change promoter is selected from the group consisting of (C1-C 20 )alkyl-NH2, (C1-C 20 )alkyl-NH-(C1-C 20 )alkyl, (C1-C 20 )alkyl-N((C1-C 20alkyl)2, (C5-C 20 )-alkyl-NH-CO-(C1-C 20 )-alkyl, (C1-C 20 )-alkyl-N(CO-(C1-C 20 )-alkyl)2, and isomers thereof. In one embodiment, the composition of the present application is one wherein the one or more PCMs (bl) capable of acting as a color- or fluorescence- change promoter is (C1-C 20 )-alkyl-NH2, such as 1-hexadecylamine, 1-octadecylamine, and mixtures thereof. In one embodiment, the composition of the present application is one wherein the PCM (bl) capable of acting as a color- or fluorescence- change promoter is 1-octadecylamine. In one embodiment, the composition of the present application comprises one or more PCMs (bl) capable of acting as a color- or fluorescence- change promoter that is a triglyceride. In one embodiment, the composition of the present application is one wherein the one or more PCMs (bl) capable of acting as a color- or fluorescence- change promoter is a triglyceride selected from the group consisting of glyceryl trinonanoate, glyceryl trilaurate, glyceryl trimyristate, glyceryl tripalmitate, and glyceryl tristearate. The term "triglyceride" refers to an ester derived from glycerol and 1, 2, or 3 fatty acids, in particular selected from the group consisting of CH2(OCO(C1-C 30 )alkyl)-CH(OCO(C1-C 30 )alkyl)-CH2(OCO(C1-C 30 )alkyl). Each "alkyl" term independently refers to a saturated straight chain or branched hydrocarbon chain containing the number of carbon atoms specified in the specification or claims.

[0098] The composition of the present application comprises one or more PCMs (b2) that are not capable of acting as a color- or fluorescence- change promoter. The term "not capable of acting as a color- or fluorescence- change promoter" refers to a compound that is not capable of initiating a change in color or luminescence, increasing the speed of change, and / or increasing the dynamic range of the color- or fluorescence- change. In one embodiment, the composition comprises one or more PCMs (b2) that are not capable of acting as a color- or fluorescence- change promoter selected from the group consisting of alkane-based PCMs, alkene-based PCMs, alkyne-based PCMs, and mixtures thereof. In one embodiment, the composition comprises one or more PCMs (b2) that are not capable of acting as a color- or fluorescence- change promoter selected from the group consisting of (C8-C 52 )alkane-based PCMs, (C 14 -C 50 )alkene-based PCMs, (C 14 -C 50PCM of alkanes, of alkenes, of alkynes and mixtures thereof. In one embodiment, the composition comprises one or more PCMs (b2) that cannot act as a color change or fluorescence color change promoter selected from PCMs of alkanes (b2a), PCMs of alkenes (b2b), PCMs of alkynes (b2c) and mixtures thereof. In one embodiment, the composition comprises one or more PCMs (b2) that cannot act as a color change or fluorescence color change promoter selected from PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. In one embodiment, the composition comprises one or more PCMs (b2) that cannot act as a color change or fluorescence color change promoter selected from PCMs of alkanes (b2a) and PCMs of alkenes (b2b). 10 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 52 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 16 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 50 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 16 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 50 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof.

[0099] In one embodiment, the composition comprises one or more PCMs (b2) that cannot act as a color change or fluorescence color change promoter selected from PCMs of alkanes (b2a), PCMs of alkenes (b2b), PCMs of alkynes (b2c) and mixtures thereof. 10 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 52 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 16 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 50 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 16 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 50 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 16 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 50 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 16 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 50 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 10 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. 52 - PCMs of alkanes (b2a), PCMs of alkenes (b2b) and mixtures thereof. The term "alkane" means a saturated branched or straight chain hydrocarbon containing the number of carbon atoms specified in the specification or claims. The term "alkene" means a branched or straight chain hydrocarbon containing the number of carbon atoms specified in the specification or claims and having at least one carbon-carbon double bond. The term "alkyne" means a branched or straight chain hydrocarbon containing the number of carbon atoms specified in the specification or claims and having at least one carbon-carbon triple bond. In one embodiment, the composition of the application is a composition comprising one or more PCMs that cannot act as a color change or fluorescence color change promoter selected from tetradecane, pentadecane, eicosane (EC), tetracosane, hexacosane, octacosane (OC), nonacosane, triacontane, docosane, tricosane, tetracosane, tetranonacosane, pentacontane and pentatetracontane; in particular, the composition of the application comprises one or more PCMs that cannot act as a color change or fluorescence color change promoter selected from eicosane (EC) and octacosane (OC).

[0100] dye

[0101] The photo-induced thermochromic composition of the present application comprises one or more dyes (c) selected from the group consisting of c1 ) dyes capable of changing their color or luminescence properties when the PCM changes between the solid state and the liquid state, and c2) dyes incapable of changing their color or luminescence properties when the PCM changes between the solid state and the liquid state.

[0102] For the purposes of the present application, the term "dye" means any substance having a color or luminescence property, which means that the substance is a colored substance, a luminescent substance (i.e. a fluorescent or phosphorescent substance) and a substance capable of becoming colored and / or luminescent (i.e. fluorescent luminescence and / or phosphorescent luminescence).

[0103] Capable dyes

[0104] In one embodiment, the composition of the present application comprises dyes (b1 ) capable of changing their color or luminescence properties when the PCM changes between the solid state and the liquid state. The term "dyes capable of changing their color or luminescence properties when the PCM changes between the solid state and the liquid state" means dyes which inherently are capable of showing a coloration, a decoloration, a color change, a luminescence quenching (e.g. fluorescence quenching or phosphorescence quenching), a luminescence activation (e.g. fluorescence activation or phosphorescence activation) or a luminescence (i.e. fluorescence or phosphorescence) change when the PCM changes from the solid state to the liquid state, from the liquid state to the solid state or both. This means that these dyes have the ability to show a coloration, a decoloration, a color change, a luminescence quenching (e.g. fluorescence quenching or phosphorescence quenching), a luminescence activation (e.g. fluorescence activation or phosphorescence activation) or a luminescence (i.e. fluorescence or phosphorescence) change by themselves without the need of the presence of a color change or fluorescence color change promoter.

[0105] - color changing dyes

[0106] The photo-induced thermochromic composition comprises one or more dyes selected from dyes which change their color depending on the aggregation / proximity state and / or the temperature. The dyes whose color depends on the aggregation / proximity state are selected from dyes which form J-aggregates and H-aggregates which show a color different from the non-aggregated state. Examples of these dyes include, but are not limited to, polycyclic aromatic hydrocarbons and cyanine dyes.

[0107] - luminescence changing dyes

[0108] The photo-induced thermoluminescent composition comprises one or more luminescent agents. Generally, the term "luminescent agent" means any compound capable of emitting, in the form of UV, visible or NIR radiation, the energy previously absorbed during the exposure to the radiation excitation. The luminescence can be, but is not limited to, fluorescence or phosphorescence.

[0109] In one embodiment, the photo-induced thermochromic luminescent composition comprises one or more dyes selected from dyes that change their luminescence depending on the aggregation / proximity state and dyes that have viscosity / stiffness dependent luminescence.

[0110] The dyes that depend on the aggregation / proximity state are selected from dyes that form J-aggregates and H-aggregates, aggregation-induced emission (AIE) dyes, aggregation-caused quenching (ACQ) dyes and dyes that form excitons. Examples of these dyes are, but are not limited to, polycyclic aromatics such as perylene, pyrene, anthracene, rubrene, rhodamine B base (RhB), tetraphenyl ethylene (TPE) and derivatives thereof, such as 9,10-dimethylanthracene, 9,10-diphenylanthracene, 9,10-dicyanoanthracene (DCA) and 1,3,6,8-tetraphenylpyrene.

[0111] In one embodiment, the photo-induced thermochromic luminescent composition is a composition in which the luminescence of one or more luminescent agents depends on the viscosity / stiffness of the medium. In one embodiment, the photo-induced thermochromic luminescent composition is a composition in which the one or more luminescent agents are {[5'-(p-hydroxyphenyl)-2,2'-bithiophen-5-yl]-methylene}-malononitrile (NIAD-4) and TPE.

[0112] Incapable dyes

[0113] In one embodiment, the composition of the application comprises a dye (b2) that is not able to change its color or luminescence properties when the PCM changes between the solid state and the liquid state. The term "dye that is not able to change its color or luminescence properties when the PCM changes between the solid state and the liquid state" means a dye that intrinsically does not show coloration, decoloration, color change, luminescence quenching (e.g. fluorescence quenching or phosphorescence quenching), luminescence activation (e.g. fluorescence activation or phosphorescence activation) or luminescence (i.e. fluorescence or phosphorescence) change when the PCM changes from the solid state to the liquid state, from the liquid state to the solid state or both. This means that these dyes intrinsically do not have the ability to show coloration, decoloration, color change, luminescence quenching, luminescence activation or luminescence change by themselves, but they can show coloration, decoloration, color change, luminescence quenching, luminescence activation or luminescence change in the presence of a color change or fluorescence color change promoter.

[0114] - color changing dyes

[0115] In one embodiment, the photo-induced thermochromic luminescent composition comprises one or more dyes selected from charge transfer dyes (redox dyes), pH responsive dyes, polarity dependent dyes.

[0116] In one embodiment, the photo-induced thermochromic composition comprises one or more pH responsive dyes. Examples of pH responsive dyes are, but are not limited to, spironolactone, spiropyrans, spiroxazines, oxazine, fluorane and chromene dyes. These dyes change their color upon hydrogen bond interaction or acid-base reaction with a color developer or with a PCM which is able to act as color developer in the solid or liquid state.

[0117] In one embodiment, the photo-induced thermochromic composition comprises one or more redox dyes. Examples of redox dyes include, but are not limited to, methylene blue, methyl viologen, azure B, thionine acetate, safranin O and neutral red. These dyes change their color upon formation of a charge transfer complex with a color developer (electron donor / acceptor) or with a PCM which is able to act as color developer in the solid or liquid state.

[0118] - Dyes that change luminescence

[0119] In one embodiment, the photo-induced thermoluminescent composition comprises one or more luminescent agents selected from charge transfer dyes (redox dyes), pH responsive dyes, polarity dependent dyes, pH sensitive luminescent dyes and redox luminescent agents.

[0120] In one embodiment, the photo-induced thermoluminescent composition is a composition wherein the one or more luminescent agents are pH sensitive luminescent agents. In one embodiment, the photo-induced thermoluminescent composition is a composition wherein the one or more luminescent agents are pH sensitive luminescent agents selected from fluorescein, rhodamine 6G, RhB and derivatives (e.g. derivatives of coumarin and fluorane).

[0121] In one embodiment, the photo-induced thermoluminescent composition is a composition wherein one or more luminescent agents are redox luminescent dyes. In one embodiment, the photo-induced thermoluminescent composition is a composition wherein the one or more luminescent agents are redox luminescent agents selected from derivatives of polycyclic aromatic hydrocarbons. In one embodiment, the photo-induced thermoluminescent composition is a composition wherein the one or more luminescent agents are selected from RhB, perylene diimide (PDI), N,N'-bis(sec-butyl)-1,6,7,12-tetra-(4-tert-butylphenoxy)perylene-3,4:9,10- tetracarboxylic acid diimide (PTDI) and DCA, which change their luminescence upon interaction with an electron donor or acceptor.

[0122] Suitable dyes and color or fluorescence color change promoters, their amounts and specific experimental conditions suitable for photo-induced changes in optical properties can be easily determined by the person skilled in the art depending on the type of dye and the composition, self-supporting film or article to be prepared. For example, the composition of the present application comprises RhB as dye and an acidic promoter or an acidic PCM, wherein the photo-induced luminescence is performed in the liquid state of the PCM.

[0123] In one embodiment, the photo-induced thermochromic or thermoluminescent composition comprises from 0.005 to 5% by weight of the composition of one or more dyes as defined above. In one embodiment, the photo-induced composition is a thermochromic composition comprising from 0.1 to 5% by weight of the composition, in particular from 1.4 to 3% by weight of the composition, of one or more dyes as defined above. In one embodiment, the photo-induced composition is a thermoluminescent composition comprising from 0.01 to 2.5% by weight of the composition of one or more dyes as defined above. The term "percent by weight (%)" means the percentage of each ingredient of the composition with respect to the total weight. The composition of the application contains a low content of dyes which are uniformly distributed in the material and provide a uniform color.

[0124] Color developer

[0125] The photo-induced thermochromic composition of the application can comprise one or more color developers. In particular, when the PCM is not able to act as a color change promoter (b2) and the dye is not able to change its color or luminescent properties when the PCM changes between solid and liquid state (c2), the photo-induced thermochromic or thermoluminescent composition further comprises one or more color developers as color change promoters. Even when the PCM is able to act as a color change promoter (bl) or the dye is able to change its color properties when the PCM changes between solid and liquid state (cl), the photo-induced thermochromic composition optionally comprises (d) one or more color developers as color change promoters. The term "color developer" means a compound able to induce a change in the color properties of a dye, for example a coloration / colour change of the dye.

[0126] Regardless of whether the color developer is a PCM (bl), the color developer interacts with the dye in its solid or liquid state. The type of interaction inducing a change in color can be hydrogen bonding, acid-base reaction (proton transfer) and / or electron transfer.

[0127] In one embodiment, the composition comprises a color developer selected from an acid, a base, a hydrogen bonding compound, an electron transfer compound or a mixture thereof. Examples of suitable acid color developers for the application include, but are not limited to, acids, alcohols and mixtures thereof.

[0128] Examples of suitable base color developers for the application include, but are not limited to, amines and mixtures thereof. Examples of suitable hydrogen bonding compounds for the application include, but are not limited to, acids, alcohols, amines and mixtures thereof. Examples of suitable electron transfer compounds for the application include, but are not limited to, thiols, amines and mixtures thereof.

[0129] In one embodiment, the developer is a lipophilic "developer" as defined above. The terms "lipophilic", "hydrophobic" and "non-polar" have the same meaning and are used interchangeably. They refer to compounds that are soluble in neutral, non-polar solvents but not in water. Lipophilic molecules can generally form aggregates in water that can only be re-dispersed in water but not dissolved.

[0130] As known to the person skilled in the art, a parameter that can be used to determine whether a compound is hydrophilic or lipophilic is the determination of its partition coefficient (P). The partition (P) coefficient is the ratio of the concentrations of a particular compound in a mixture of two immiscible phases at equilibrium. Typically, one of the solvents chosen is water and the second is hydrophobic, for example octanol. Hydrophobic active ingredients have a high octanol / water partition coefficient and hydrophilic compounds have a low octanol / water partition coefficient. The log P value is also known as a measure of lipophilicity / hydrophilicity. The logarithm of the ratio of the concentrations of the unionized solute in the solvents at a particular pH is known as log P. The log P value is also known as a measure of lipophilicity:

[0131]

[0132] wherein "solute" is the active ingredient.

[0133] For the purposes of the present application, a compound is considered "lipophilic" when the log P value is equal to or greater than 2.4.

[0134] In one embodiment, the developer is selected from the group consisting of PCM dodecanoic acid, stearic acid, 1-tetradecanol, 1-hexadecanol, dodecyl phosphonic acid, octyl p-hydroxybenzoate, bisphenol A.

[0135] For acidotropic dyes, the exchange of protons between the developer (capable of donating / accepting protons) and the dye (capable of accepting / donating protons) causes a change in the color of the dye. In one embodiment, the photo-induced thermochromic composition of the present application comprises a developer selected from the group consisting of PCM dodecanoic acid, stearic acid, 1-tetradecanol, 1-hexadecanol, dodecyl phosphonic acid, octyl p-hydroxybenzoate, bisphenol A. For dyes that change color upon the establishment of hydrogen-bonding interactions, the formation of these interactions between the dye and the developer induces the development of color. For dyes that change their color upon the formation of charge transfer complexes by electron transfer, the interaction of the dye with the electron donor / acceptor produces the development of color.

[0136] In one embodiment, the photo-induced thermochromic composition comprises one or more developers as defined in the present application in an amount ranging from 0.1 to 15% by weight of the composition, in particular from 1 to 10% by weight of the composition.

[0137] Luminescence activator

[0138] The photo-induced thermochromic luminescent composition of the present application can comprise one or more luminescence activators. In particular, when the PCM is not able to act as a fluorescence color change promoter (b2) and the dye is not able to change its luminescence properties when the PCM changes between solid and liquid state (c2), the photo-induced thermochromic luminescent composition further comprises one or more fluorescence color change promoters as luminescence activators. Even when the PCM is able to act as a fluorescence color change promoter (bl) or the dye is able to change its luminescence properties when the PCM changes between solid and liquid state (cl), the photo-induced thermochromic luminescent composition can optionally comprise (d) one or more fluorescence color change promoters as luminescence activators. The term "luminescence activator" refers to a compound able to induce an enhancement of the luminescence of the dye.

[0139] In one embodiment, the color change or fluorescence color change promoter is a luminescence activator selected from the group consisting of singlet, triplet sensitizers, fluorescence resonance energy transfer (FRET) sensitizers, and electron transfer sensitizers, and mixtures thereof.

[0140] In one embodiment, the luminescence activator is selected from the group consisting of benzophenone, perylene, pyrene, cyanine and boron-dipyrromethene (BODIPY) derivatives, platinum octaethylporphyrin, palladium tetranthra-porphyrin.

[0141] In one embodiment, the photo-induced thermochromic luminescent composition comprises one or more luminescence activators as defined in the present application in an amount ranging from 0.001 to 10% by weight of the composition. In one embodiment, the photo-induced thermochromic luminescent composition comprises one or more luminescence activators as defined in the present application in an amount ranging from 0.01 to 9% by weight of the composition.

[0142] luminescence quencher

[0143] The photo-induced thermochromic luminescent composition of the present application can comprise one or more luminescence quenchers. In particular, when the PCM is not able to act as a fluorescence color change promoter (b2) and the dye is not able to change its luminescence properties when the PCM changes between solid and liquid state (c2), the photo-induced thermochromic luminescent composition further comprises one or more fluorescence color change promoters as luminescence quenchers. Even when the PCM is able to act as a fluorescence color change promoter (bl) or the dye is able to change its luminescence properties when the PCM changes between solid and liquid state (cl), the photo-induced thermochromic luminescent composition can optionally comprise (d) one or more fluorescence color change promoters as luminescence quenchers. The term "luminescence quencher" refers to a compound able to induce an inhibition of the luminescence of the dye. The type of interaction inducing the inhibition of the luminescence is governed by energy and / or electron transfer.

[0144] In one embodiment, the luminescence quencher is selected from the group consisting of RET quenchers, triplet state quenchers, electron transfer quenchers and mixtures thereof.

[0145] In one embodiment, the luminescence quencher is selected from the group consisting of perylene, pyrene, anthracene, amines and mixtures thereof.

[0146] In one embodiment, the amount of luminescence quencher as defined in the present application is comprised between 0.001 and 0.5% by weight of the composition. In one embodiment, the amount of luminescence quencher as defined in the present application is comprised between 0.005 and 0.1% by weight of the composition.

[0147] Capsules

[0148] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises capsules. In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises capsules selected from the group consisting of nanocapsules and microcapsules.

[0149] The term "microcapsules" refers to capsules having a dimension in the micrometer scale, i.e. a diameter greater than 0.20 pm, and having any shape or morphology. In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises microcapsules as defined herein having a particle size of 0.21 to 400 pm as measured by SEM. In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises capsules as defined above having a particle size of 0.5 pm to 5 pm as measured by SEM or master sizer.

[0150] The term "nanocapsules" refers to capsules having a dimension in the nanometer scale, i.e. a diameter of 20 to less than 200 nm, and having any shape or morphology. In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises nanocapsules as defined above having a particle size of 30 nm to 150 nm as measured by SEM, transmission electron microscopy (TEM) and DLS. Said nanocapsules are advantageous because they allow to obtain transparent materials, e.g. film-forming materials, upon incorporation with polymeric agents, which is suitable for optical applications requiring transparency. Said nanocapsules are also advantageous because they allow for biomedical applications. The reduced size allows for the passage through cell membranes.

[0151] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises capsules selected from the group consisting of core-shell microcapsules or nanocapsules and solid lipid microparticles or nanoparticles.

[0152] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises core-shell microcapsules or nanocapsules. The term "core-shell capsules" refers to capsules formed by a core and a shell surrounding at least a portion of said core.

[0153] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises a core-shell microcapsule or nanocapsule, wherein the core comprises one or more core-forming materials. In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises a core-shell microcapsule or nanocapsule, wherein the core comprises one or more PCM as defined herein as core-forming material. Examples of core-forming materials suitable for use in the present application include, but are not limited to, eicosane, stearic acid and mixtures thereof.

[0154] The photo-induced thermochromic or thermoluminescent composition of the present application comprises a core-shell microcapsule or nanocapsule, wherein the shell comprises one or more polymeric shell materials selected from the group consisting of organic polymeric shell materials and inorganic polymeric shell materials. Examples of organic polymeric shell materials suitable for use in the present application include, but are not limited to, linear or cross-linked poly(methyl methacrylate), polystyrene, polyamide, polyurea, polyurethane, polycarbonate, polysulfone, polyethersulfone, polyetherimide and mixtures thereof. Examples of inorganic polymeric shell materials suitable for use in the present application include, but are not limited to, Si02, Ti02, V02and mixtures thereof. This structuration is particularly advantageous as the shell limits the core material, in particular the PCM, avoiding their diffusion and allowing reproducible color or luminescence changes.

[0155] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises solid lipid microparticles or nanoparticles. The term "solid lipid particle" or "SLP" refers to a capsule having a solid lipid core matrix. The term "lipid" is used herein in a broader sense and includes triglycerides (e.g. tristearin), alkanes (e.g. eicosane), diglycerides (e.g. glycerol monostearate), monoglycerides (e.g. glycerol monostearate), fatty acids (e.g. stearic acid), steroids (e.g. cholesterol) and waxes (e.g. cetyl palmitate). This means that the SLP does not have a shell material surrounding the solid lipid core matrix. This structuration is particularly advantageous as it allows easier processing, but requires additional treatment (e.g. coating or embedding) with polymeric materials to avoid diffusion and leakage of the matrix-forming agent, in particular the PCM in liquid state.

[0156] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the present application comprises SLPs, wherein the SLPs comprise one or more PCM. Examples of PCM suitable for use in the present application include, but are not limited to, eicosane, stearic acid and mixtures thereof.

[0157] In one embodiment, the photoinduced thermochromic or thermoluminescent composition of the present application comprises SLPs, wherein said SLPs further comprise one or more suitable thermoplastic polymers including, but not limited to, polystyrene (PS), polyether sulfone, polycarbonate, polymethyl methacrylate, polyetherimide and mixtures thereof. These compositions comprise thermoplastic polymers, allowing irreversible color or luminescence changes.

[0158] In one embodiment, the photoinduced thermochromic or thermoluminescent composition of the present application comprises SLPs, wherein said SLPs comprise a mixture of one or more PCMs as defined herein and one or more thermoplastic polymers as defined above, wherein the content of said thermoplastic polymers is equal to or higher than 50% by weight of said SLPs.

[0159] In one embodiment, the photoinduced thermochromic or thermoluminescent composition of the present application comprises capsules, wherein said capsules comprise said PCMs, one or more dyes and, if necessary, one or more color or fluorescence coloration promoters inside the nanoparticles. The compositions of the present application comprising these capsules are advantageous because they allow having a close contact between said nanoparticles and PCMs. Thus, said capsules can be used as inks or paints to prepare coatings or films. Said capsules can be embedded in films or coatings of polymeric materials of different nature.

[0160] In one embodiment, the photoinduced thermochromic or thermoluminescent composition of the present application comprises capsules, wherein said capsules comprise one or more dyes and, if necessary, one or more color or fluorescence coloration promoters inside the PCMs. This means that said nanoparticles are not inside said capsules, but they are uniformly distributed in the excipient or medium forming a part of the coating, self-supporting film or embedded article as defined below; or said nanoparticles are in the shell material, inside said shell or attached to said shell as shell-forming material. For example, said nanoparticles can be uniformly distributed in a self-supporting film material in which said capsules are embedded. The compositions of the present application comprising these capsules are advantageous because they allow obtaining films or coatings of different materials containing said capsules. Moreover, said capsules uniformly distributed in the polymeric coating or film allow the heat generated by the nanoparticles, in particular MPs, to reach quickly all the capsules, inducing a fast color or luminescence change.

[0161] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application comprising capsules as defined above takes the form of a suspension composition comprising an external phase and capsules as defined in the application suspended in this phase. In one embodiment, the external phase comprises one or more solvents selected from the group consisting of water, organic solvents and mixtures thereof. In one embodiment, the external phase comprises one or more solvents selected from the group consisting of water, methanol, ethanol, acetone, hexane, dimethylformamide and mixtures thereof, in particular water. In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application takes the form of a suspension composition as defined above, wherein the capsules comprise inside the nanoparticles the PCM, one or more dyes and if necessary one or more color change or fluorescence color change promoters. In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application takes the form of an aqueous suspension composition, wherein the capsules comprise inside the PCM one or more dyes and if necessary one or more color change or fluorescence color change promoters. This means that the nanoparticles are not inside the capsules, but they are uniformly distributed in the external phase or form part of the shell or are deposited on the shell material of the capsules. The method for preparing the above suspensions, in particular aqueous suspensions, is also part of the present application.

[0162] In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application comprising capsules as defined above takes the form of a dry powder composition. In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application takes the form of a dry powder composition, wherein the capsules comprise inside the nanoparticles the PCM, one or more dyes and if necessary one or more color change or fluorescence color change promoters. In one embodiment, the photo-induced thermochromic or thermoluminescent composition of the application takes the form of a dry powder composition, wherein the capsules comprise inside the PCM one or more dyes and if necessary one or more color change or fluorescence color change promoters. This means that the nanoparticles are not inside the capsules, but they are present in the powder outside the capsules or form part of the shell or are deposited on the shell material of the capsules. The method for preparing the above dry powder compositions is also part of the present application, which comprises sending the suspension as defined above to spray drying, freeze drying or solvent evaporation conditions to eliminate the solvent of the suspension.

[0163] In one embodiment, the composition of the application further comprises additional components selected from the group consisting of pharmaceutically active ingredients and reactive oxygen species. If present, these components are generally mixed with the PCM(s) forming part of the composition of the application.

[0164] All the embodiments related to the components as defined for the photoinduced thermochromic or thermoluminescent composition as defined in the present application also apply to the capsule, aqueous suspension and dry powder composition as defined in the present application.

[0165] Photoinduced thermochromic or thermoluminescent self-supporting film

[0166] As disclosed above, the second aspect of the present application relates to a photoinduced thermochromic or thermoluminescent self-supporting film comprising a photoinduced thermochromic or thermoluminescent composition as defined in the present application, one or more polymers and optionally one or more excipients.

[0167] As used herein, the term "self-supporting film" refers to a thin film having a physically stable shape, dimensionally stable on its cast surface and which can be removed from the cast surface without having to be supported on a large part of its surface area.

[0168] The photoinduced thermochromic or thermoluminescent self-supporting rigid or flexible film of the present application optionally comprises one or more excipients which allow to generate the desired shape for the photoinduced thermochromic or thermoluminescent composition. Suitable excipients and their amounts can be easily determined by the person skilled in the art depending on the type of forming material to be prepared. Suitable excipients can be stabilizers to prevent aggregation of the MPs and capsules. The preparation of these photoinduced thermochromic or thermoluminescent self-supporting films can be carried out by methods known in the art. Generally, the preparation of self-supporting films implies the use of extrusion, stretching, injection molding, casting, in situ polymerization, spray coating, spin coating, blade coating and roll-to-roll coating. The film is removed from the substrate by, for example, peeling off the film or dissolving the substrate.

[0169] As disclosed above, all the embodiments related to the components as defined for the photoinduced thermochromic or thermoluminescent composition as defined in the present application also apply to the photoinduced thermochromic or thermoluminescent self-supporting film of the second aspect of the present application. The photoinduced thermochromic or thermoluminescent self-supporting film is considered as a material / composition which can be used in end applications.

[0170] Photoinduced thermochromic or thermoluminescent article

[0171] As disclosed above, the third aspect of the present application relates to a photoinduced thermochromic or thermoluminescent article comprising a photoinduced thermochromic or thermoluminescent composition as defined in the first aspect of the present application or a photoinduced thermochromic or thermoluminescent self-supporting film as defined in the second aspect of the present application.

[0172] The photoinduced thermochromic or thermoluminescent article is considered as a material / composition which can be used in end applications.

[0173] In one embodiment, the photo-induced thermochromic or thermoluminescent article is a coated article (A) comprising: a substrate, and a photo-induced thermochromic or thermoluminescent coating deposited on the surface of the substrate, wherein: the coating comprises the composition as defined in the present application and optionally one or more coating forming agents. The term "coated article" refers to an article comprising a substrate covered by one or more layers formed by a coating composition. In one embodiment, the coated article is selected from the group consisting of single layer, double layer and multi-layer coated articles. For the purpose of the present application, the coating of a substrate with a thermochromic or thermoluminescent composition can be performed by any method known in the art for coating any surface. Examples of suitable substrates for the present application include, but are not limited to, non-porous and porous substrates. The photo-induced thermochromic or thermoluminescent coating composition optionally comprises one or more coating forming agents. Suitable excipients and amounts thereof can be easily determined by the person skilled in the art depending on the type of substrate to be coated. In one embodiment, the photo-induced thermochromic or thermoluminescent article comprises a substrate selected from the group consisting of glass, polymeric sheet, textile material, cellulosic material and wood, transparent or non-transparent substrates and curved or planar substrates.

[0174] In one embodiment, the photo-induced thermochromic or thermoluminescent article is an embedded article (B) comprising: a porous substrate; a photo-induced thermochromic or thermoluminescent composition as defined in the first aspect of the present application embedded in the porous substrate; and optionally one or more additional external coatings. The term "embedded article" refers to an article formed from a porous substrate containing a photo-induced thermochromic or thermoluminescent composition inside the pores.

[0175] In particular, the photoinduced thermochromic or thermoluminescent composition is deposited on the surface of the substrate and through the apertures. For the purposes of the present application, the term "porous substrate" refers to a substrate having a plurality of apertures or through holes that allow the photoinduced thermochromic or thermoluminescent composition to pass through the substrate. These articles are advantageous because the apertures of the substrate prevent the diffusion of the photoinduced thermochromic or thermoluminescent composition, particularly those that take the form of SLPs or as unstructured materials. For the purposes of the present application, the process of making the embedded articles of the present application can be carried out by any method known in the art. Examples of methods suitable for the present application include, but are not limited to, casting, in situ polymerization (in cases where a polymer matrix is required), spray coating, spin coating, doctor blade coating, and substrate immersion. The photoinduced thermochromic or thermoluminescent article can optionally comprise one or more excipients or carriers. Suitable excipients or carriers and amounts thereof can be readily determined by one skilled in the art depending on the type of substrate to be embedded. The photoinduced thermochromic or thermoluminescent article is an embedded article optionally comprising one or more additional external coatings. These additional external coatings can be water-resistant coatings, corrosion-resistant coatings, scratch-resistant coatings, and the like. The compositions and methods for making these additional external coatings can be readily determined by one skilled in the art depending on the type of external coating to be made. These embedded articles of the present application are advantageous because they allow the use of uniformly dispersed low concentrations of nanoparticles to uniformly change color or luminescence throughout the substrate.

[0176] The photoinduced thermochromic or thermoluminescent compositions of the present application are advantageous because of their versatility and usefulness for coating a large number of types of substrates, particularly porous substrates. In one embodiment, the photoinduced thermochromic or thermoluminescent porous substrate is selected from the group consisting of substrates based on textiles, substrates based on polyamides, substrates based on polyesters, substrates based on cellulose, and mixtures thereof. In one embodiment, the photoinduced thermochromic or thermoluminescent porous substrate is selected from the group consisting of paper, banknotes, wood, and cotton.

[0177] In one embodiment, the photoinduced thermochromic or thermoluminescent article is an article containing a self-supporting film comprising one or more photoinduced thermochromic or thermoluminescent self-supporting films as defined in the present application. The definition of the term "self-supporting" as defined above for the film also applies to the "article" containing it.

[0178] The photoinduced thermochromic or thermoluminescent coating of the photoinduced thermochromic or thermoluminescent coated article, the photoinduced thermochromic or thermoluminescent embedded article, and the article containing a self-supporting film can cover the surface of the substrate, or can be sandwiched between two or more surfaces (or layers), for example, between glass or polymeric sheets.

[0179] In one embodiment, the photo-induced thermochromic or thermoluminescent article comprises a transparent photo-induced thermochromic or thermoluminescent composition or a self-supporting film, which comprises nanocapsules having a particle size of 20-150 nm, measured by SEM, TEM and DLS methods. The transparent photo-induced thermochromic or thermoluminescent compositions or self-supporting films of the present invention are advantageous because when the final article is also transparent (which means that the substrate is also transparent) they can be used in the field of optical devices. Alternatively, the photo-induced thermochromic or thermoluminescent compositions or self-supporting films of the present invention on top of an opaque substrate can be used to allow the observation of the appearance of the coated article through the film without changing their features.

[0180] In one embodiment, the photo-induced thermochromic or thermoluminescent article comprises a photo-induced thermochromic or thermoluminescent composition comprising capsules, wherein the nanoparticles, one or more PCMs, one or more dyes and, if necessary, one or more chromotropic or fluorochromotropic promoters are inside the capsules.

[0181] In one embodiment, the photo-induced thermochromic or thermoluminescent article comprises a photo-induced thermochromic or thermoluminescent composition comprising capsules, wherein the one or more PCMs, one or more dyes and, if necessary, one or more chromotropic or fluorochromotropic promoters are inside the capsules, and the nanoparticles are dispersed in the excipient and / or carrier, embedding material or self-supporting film forming the coating, or form part of the shell.

[0182] In one embodiment, the photo-induced thermochromic or thermoluminescent substrate of the present invention comprises a photo-induced thermochromic or thermoluminescent coating deposited on the surface or embedded in the surface or forming a self-supporting film, having a thickness of 0.01 pm to 1000 pm. This is advantageous because it provides the final article with the function of NIR-induced thermochromic or thermoluminescent properties.

[0183] The change in colour or luminescence of the article of the present invention induced by the temperature increase promoted by the irradiation by low-energy radiation (NIR) as defined above is rapid, uniform, intense. This change can be reversible or irreversible.

[0184] In one embodiment, the distribution of nanoparticles in the photo-induced thermochromic or thermoluminescent article as defined above is between 0.0001 and 0.01 mg of nanoparticles per mm2. 2 Substrate 0.000008 to 0.00014 mg of nanoparticles.

[0185] All the embodiments related to the components as described above for the photo-induced thermochromic or thermoluminescent compositions and the formed materials as defined in the present invention, also apply to the photo-induced thermochromic or thermoluminescent article of the third aspect of the present invention.

[0186] Preparation of photo-induced thermochromic or thermoluminescent compositions

[0187] The method for preparing the photo-induced thermochromic or thermoluminescent compositions of the first aspect of the present application is also part of the present application.

[0188] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition does not comprise capsules, the method comprises: preparing a solution of the PCM and one or more dyes and, if necessary, one or more chromotropic or fluorochromic promoters; and mixing the solution thus obtained with the nanoparticles as defined in the present application.

[0189] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is configured as capsules as defined in the present application, the method comprises preparing the capsules by any method known in the art.

[0190] In one embodiment, the capsules are SLP capsules, which comprise inside the nanoparticles, one or more PCMs, one or more dyes and, if necessary, one or more chromotropic or fluorochromic promoters. The method comprises implementing an emulsification / cooling process, a spontaneous emulsification / solvent displacement process, a emulsion-solvent evaporation or hot extrusion process, in particular an emulsification / cooling process. As an example, a more detailed description of a general procedure for preparing a composition comprising SLP capsules is provided. First, the dyes and, if necessary, one or more chromotropic or fluorochromic promoters are dissolved in the PCM in its molten state (optionally the nanoparticles and other excipients such as surfactants can be included). Next, the organic phase thus obtained is mixed with an aqueous phase formed by water and one or more excipients such as surfactants. The emulsification process is carried out by any method known in the art, such as high or low energy methods. In high energy methods, homogenization is carried out by stirring, high shear homogenization, ultrasound, membrane filtration or high pressure homogenization. Low energy methods include spontaneous emulsification and phase inversion methods. After obtaining the emulsion (the droplet size depends on the emulsification method), it is transferred to an aqueous solution maintained at 5°C to induce the cooling and freezing of the PCM.

[0191] In one embodiment, the capsules are core-shell capsules, which contain inside the nanoparticles, the PCM(s), the dye(s) and, if needed, the colour-change or fluorescence colour-change promoter(s). The process for their preparation comprises carrying out an interfacial polymerization process, a radical polymerization process, a coacervation process, an in situ polymerization process and a solvent evaporation / phase separation process, in particular a phase separation / shell formation process. As an example, a more detailed description of a general procedure for the preparation of a composition comprising core-shell capsules is provided. First, the shell-forming material (shell polymer), the dye(s) and, if needed, the colour-change or fluorescence colour-change promoter(s) and the PCM are dissolved in a volatile organic solvent immiscible with water (optionally the nanoparticles and one or more excipients such as surfactants can be included). Subsequently, the organic phase thus obtained is mixed with an aqueous phase formed by water and one or more excipients such as surfactants. The emulsification process is carried out by any method known in the art, such as high or low energy methods. In the high energy methods, homogenization is carried out by stirring, high shear homogenization, ultrasound, membrane filtration or high pressure homogenization. The low energy methods include spontaneous emulsification and phase inversion methods. After obtaining the emulsion (the droplet size depends on the emulsification method), the organic solvent is evaporated, inducing the precipitation of the shell-forming material (shell polymer) around the PCM droplets, which solidify upon solvent evaporation.

[0192] In one embodiment, the capsules are SLPs or core-shell capsules, which contain inside the PCM(s), the dye(s) and, if needed, the colour-change or fluorescence colour-change promoter(s). In this case, the process comprises preparing the capsules as disclosed above following the procedures disclosed above, but containing the PCM, the dye(s) and, if needed, the colour-change or fluorescence colour-change promoter(s); secondly mixing the capsules obtained in the previous step with the nanoparticles of the application.

[0193] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition takes the form of a suspension, the process comprises preparing the capsules as disclosed above in water, which remain in water after synthesis or can be re-dispersed in water from a powder.

[0194] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition takes the form of a dry powder composition, the process comprises carrying out the procedures disclosed above in a suitable medium, such as water, and further drying the aqueous suspension obtained before by freeze-drying or spray-drying.

[0195] In one embodiment, the method of preparing a composition of the application as defined above further comprises the previous step of preparing nanoparticles able to absorb NIR radiation and to convert said NIR into heat. In one embodiment, the process of preparing a composition of the application as defined above further comprises the previous step of preparing nanoparticles by a templating method. The template can be provided by self-assembling template surfactants, oil droplets or solid particles.

[0196] In the case of metallic particles, the method comprises reducing the metal salt inside or around the template, reducing the metal salt by photochemistry (irradiation), thermal, electrochemical, by sonication or chemical reagents (e.g. amines). In one embodiment, the template is made of droplets of (3-aminopropyl)triethoxysilane (APTES). In one embodiment, the template is a core-shell type capsule or SLP containing a thermochromic / thermoluminescent composition. In one embodiment, the method of preparing a composition of the application as defined above further comprises the previous step of preparing nanoparticles, which comprises the one-pot synthesis of metal (e.g. gold) nanoshells by APTES suspension in water. Specifically, gold nanoshells (AuNS) are prepared by reduction of chloroauric acid in the presence of APTES nanodroplets in water. The APTES nanodroplets act as templates for the gold nanoshells. When HAuCl4 is added, it migrates to the interface between the droplet and water. When the reducing agent (NaBH4) is added, gold is reduced and the nanoshell structure is formed. To stabilize the AuNS, it is necessary to rapidly add a stabilizer such as bovine serum albumin. Suitable methods, reaction conditions and reagents, and their amounts, can be easily determined by the person skilled in the art depending on the size, shape and metal type of the MP.

[0197] In the case of non-metallic particles able to convert NIR into heat, such as semiconductor polymeric nanoparticles and cyanine dye nanoparticles, the method comprises the emulsion-solvent displacement method and the emulsion-solvent evaporation method.

[0198] Suitable methods, reaction conditions and reagents, and their amounts, can be easily determined by the person skilled in the art depending on the form of the composition and the structure of the PCM.

[0199] Preparation of a self-supporting film of photo-induced thermochromic or thermoluminescent

[0200] The method of preparing a photo-induced thermochromic or thermoluminescent self-supporting film comprising a photo-induced thermochromic or thermoluminescent composition of the second aspect of the application is also part of the application.

[0201] Suitable methods, reaction conditions and reagents, and their amounts, can be easily determined by the person skilled in the art depending on the formed article and composition and the structure of the PCM.

[0202] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is structured inside capsules, the capsules contain inside one or more PCMs, one or more dyes and, if necessary, one or more chromotropic or fluorochromic accelerators, and the preparation also comprises one or more excipients such as polymeric materials, the method comprises:

[0203] 1) mixing the capsule suspension with polymeric materials, even polymeric or monomeric substances, and nanoparticles;

[0204] 2) depositing the mixture obtained in the previous step on a substrate, in particular by spin coating, spray coating, flow coating, inkjet printing, blade coating, roll-to-roll and brushing;

[0205] 3) drying or curing the substrate obtained in the previous step to obtain a coated substrate;

[0206] 4) removing from the substrate (by peeling from the substrate or dissolving the substrate) to obtain a film suitable for application elsewhere.

[0207] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is structured inside capsules, the capsules contain inside one or more PCMs, one or more dyes and, if necessary, one or more chromotropic or fluorochromic accelerators, and the preparation also comprises one or more excipients such as polymeric materials, the method comprises:

[0208] 1) mixing the capsule suspension with polymeric materials and nanoparticles;

[0209] 2) depositing the mixture obtained in the previous step on a substrate;

[0210] 3) drying or curing the substrate obtained in the previous step to obtain a coated substrate;

[0211] 4) removing from the substrate (by peeling from the substrate or dissolving the substrate) to obtain a film suitable for application elsewhere.

[0212] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is structured inside capsules, the capsules contain inside one or more PCMs, one or more dyes and, if necessary, one or more chromotropic or fluorochromic accelerators, and the preparation also comprises one or more excipients such as polymeric materials, the method comprises:

[0213] 1) mixing the capsule suspension with monomeric substances of polymeric materials and nanoparticles;

[0214] 2) depositing the mixture obtained in the previous step on a substrate;

[0215] 3) curing the substrate obtained in the previous step to obtain a coated substrate;

[0216] 4) removing (by peeling from the substrate or dissolving the substrate) the substrate to obtain a film suitable for application elsewhere.

[0217] The film formation of the present application can be carried out by any method disclosed in the art. Typically, the film formation can be carried out by solvent evaporation from a preformed dissolved coating material, coalescence of the polymeric nanoparticle dispersion and polymerization from monomers.

[0218] Preparation of a photo-induced thermochromic or thermoluminescent article

[0219] The method of preparing a photo-induced thermochromic or thermoluminescent article of the third aspect of the present application comprising a photo-induced thermochromic or thermoluminescent composition is also part of the present application.

[0220] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is not configured in a capsule, the method comprises:

[0221] 1) depositing an aqueous solution of the nanoparticles on the substrate;

[0222] 2) drying the substrate thus obtained;

[0223] 3) depositing a liquid mixture of a PCM containing one or more dyes and, if necessary, one or more thermochromic or fluorescence coloration promoters on the substrate obtained in the previous step at a temperature higher than the melting point of the PCM;

[0224] 4) cooling the substrate obtained in the previous step, and

[0225] 5) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding a polymeric material.

[0226] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is not configured in a capsule, the method comprises:

[0227] 1) depositing a liquid mixture of a PCM containing nanoparticles, one or more dyes and, if necessary, one or more thermochromic or fluorescence coloration promoters on a substrate laminated on a hot plate at a temperature higher than the melting point of the PCM;

[0228] 2) cooling the substrate obtained in the previous step, and

[0229] 3) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding a polymeric material.

[0230] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is not structured in capsules, the method comprises:

[0231] 1 ) depositing a suspension comprising nanoparticles on a substrate;

[0232] 2) drying the substrate thus obtained in the previous step, and

[0233] 3) depositing a dry powder composition comprising a PCM, one or more dyes and, if necessary, one or more color change or fluorescence color change promoters,

[0234] 4) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding polymeric materials.

[0235] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is not structured in capsules, the method comprises:

[0236] 1 ) depositing a dry powder composition comprising a PCM, nanoparticles, one or more dyes and, if necessary, one or more color change or fluorescence color change promoters,

[0237] 2) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding polymeric materials.

[0238] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is structured in capsules, the capsules comprising internally a PCM, nanoparticles, one or more dyes and, if necessary, one or more color change or fluorescence color change promoters, the method comprises:

[0239] 1 ) depositing a suspension containing the capsules on a substrate;

[0240] 2) drying the substrate thus obtained in the previous step, and

[0241] 3) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding polymeric materials.

[0242] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is structured in capsules, the capsules comprising internally a PCM, nanoparticles, one or more dyes and, if necessary, one or more color change or fluorescence color change promoters, the method comprises:

[0243] 1 ) depositing a dry powder composition containing the capsules on a substrate;

[0244] 2) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding polymeric materials.

[0245] In one embodiment, wherein the light-induced thermochromic or thermoluminescent composition is structured in capsules, the capsules contain internally the PCM, the dye(s) and, if necessary, the color change or fluorescence color change promoter(s), but do not contain the nanoparticles, the method comprises:

[0246] 1 ) depositing a suspension of the nanoparticles on a substrate,

[0247] 2) drying the substrate thus obtained;

[0248] 3) depositing a suspension containing the capsules on the substrate obtained in the previous step,

[0249] 4) drying the substrate thus obtained; and

[0250] 5) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding polymeric materials;

[0251] or

[0252] 1 ) depositing a suspension containing the capsules on a substrate,

[0253] 2) drying the substrate thus obtained,

[0254] 3) depositing a solution of the nanoparticles on the substrate obtained in the previous step;

[0255] 4) drying the substrate thus obtained, and

[0256] 5) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding polymeric materials;

[0257] or

[0258] 1 ) depositing a suspension containing the capsules and the nanoparticles on a substrate,

[0259] 2) drying the substrate thus obtained; and

[0260] 3) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding polymeric materials;

[0261] or

[0262] 1 ) depositing a dry powder composition containing the nanoparticles forming part of the shell or in the outer part of the capsules on a substrate; and

[0263] 2) optionally, covering the substrate obtained in the previous step with one or more further coatings by adding polymeric materials;

[0264] or

[0265] 1 ) depositing a suspension containing the nanoparticles forming part of the shell or in the outer part of the capsule on a substrate,

[0266] 2) drying the substrate thus obtained; and

[0267] 3) optionally, covering the substrate obtained in the previous step with one or more additional coatings by adding polymeric materials.

[0268] In one embodiment, the light-induced thermochromic or thermoluminescent composition is deposited on the substrate using printing techniques. Typically, the suspension of nanoparticles and PCM mixture (also containing the dye(s) and, if necessary, the one or more thermochromic or fluorescence coloration promoters) are printed in one or two separate successive steps.

[0269] In one embodiment, wherein the light-induced thermochromic or thermoluminescent composition is structured inside a capsule, the capsule containing inside the nanoparticles, the PCM(s), the dye(s) and, if necessary, the one or more thermochromic or fluorescence coloration promoters, and the article further comprises one or more excipients such as polymeric materials, the method comprises:

[0270] 1 ) mixing the capsule suspension with polymeric materials (even polymeric or monomeric substances);

[0271] 2) depositing the mixture obtained in the previous step on a substrate, in particular by spin coating, spray coating, flow coating, inkjet printing, blade coating, roll-to-roll and brushing;

[0272] 3) drying or curing the substrate obtained in the previous step to obtain a coated substrate.

[0273] In one embodiment, wherein the light-induced thermochromic or thermoluminescent composition is structured inside a capsule, the capsule containing inside the PCM(s), the dye(s) and, if necessary, the one or more thermochromic or fluorescence coloration promoters, and the article further comprises one or more excipients such as polymeric materials, the method comprises:

[0274] 1 ) mixing the capsule suspension with polymeric materials and nanoparticles;

[0275] 2) depositing the mixture obtained in the previous step on a substrate;

[0276] 3) drying or curing the substrate obtained in the previous step to obtain a coated substrate.

[0277] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition is structured within a capsule, the capsule contains inside one or more PCMs, one or more dyes and, if necessary, one or more chromotropic or fluorochromotropic promoters, and the article further comprises one or more excipients such as polymeric materials, the method comprises:

[0278] 1) mixing the capsule suspension with the monomeric species of the polymeric material and the nanoparticles;

[0279] 2) depositing the mixture obtained in the previous step on a substrate;

[0280] 3) curing the substrate obtained in the previous step to obtain a coated substrate.

[0281] The coating formation of the present application can be carried out by any method disclosed in the art. Typically, the coating formation can be carried out by solvent evaporation of a pre-formed dissolved coating material, coalescence of the polymeric nanoparticle dispersion and polymerization of the monomers.

[0282] In one embodiment, when the composition of the present application comprises one or more additional components as defined above, the method comprises carrying out any of the processes disclosed above and further mixing the additional components with the PCMs.

[0283] The embodiments disclosed above for the photo-induced thermochromic or thermoluminescent composition of the first aspect of the present application, the self-supporting film and the article of the present application are also applicable to their method of preparation.

[0284] Use of photo-induced thermochromic or thermoluminescent compositions

[0285] The use of the composition, self-supporting film and article of the present application is also part of the present application.

[0286] The fourth aspect of the present application relates to their use in therapy, cosmetics, diagnostics and optical devices.

[0287] The photo-induced thermochromic or thermoluminescent compositions structured in capsules, in particular nanocapsules in the form of SLPs and core-shell capsules, can be used as imaging agents. The term "imaging agent" refers to any substance used as a marker or to enhance a particular structure in any imaging technique. For the purposes of the present application, the main imaging agent is a luminescence changing agent (after NIR irradiation) which changes the luminescence after the melting of the PCM induced by the NIR radiation. This application can be used in high resolution fluorescence microscopy. It is also advantageous because the penetration of the NIR radiation is deeper in biological tissues.

[0288] The photo-induced thermochromic or thermoluminescent compositions structured in capsules, in particular nanocapsules in the form of SLPs, can be used as drug delivery systems.

[0289] In one embodiment, wherein the photo-induced thermochromic or thermoluminescent composition further comprises one or more pharmaceutically active ingredients, they can be used for therapy. Indeed, the delivery of the active ingredients from the SLP is performed by irradiation with NIR to melt the PCM of the SLP. The delivery of the active ingredients from the photo-induced thermochromic or thermoluminescent composition can be controlled / modified / extended by monitoring the temperature induced by the irradiation with NIR light.

[0290] The photo-induced thermochromic or thermoluminescent composition can also be used in the field of optical devices. Thus, the use of the following in an optical device is also part of the present application:

[0291] - A photo-induced thermochromic or thermoluminescent composition comprising: a) nanoparticles, in particular metallic gold nanoparticles, capable of absorbing near infrared radiation (NIR) and converting said NIR radiation into heat; b) one or more phase change materials (PCM) selected from: bl) PCMs capable of acting as thermochromic or fluorochromic promoters; and b2) PCMs not capable of acting as thermochromic or fluorochromic promoters; c) one or more dyes selected from: cl) dyes capable of changing their color or luminescent properties when the PCM changes between solid and liquid state; and c2) dyes not capable of changing their color or luminescent properties when the PCM changes between solid and liquid state;

[0292] wherein: - when the PCM is not capable of acting as a thermochromic or fluorochromic promoter (b2), and the dye is not capable of changing its color or luminescent properties when the PCM changes between solid and liquid state (c2), the photo-induced thermochromic or thermoluminescent composition further comprises a thermochromic or fluorochromic promoter selected from one or more color developers, luminescence quenchers and luminescence activators; or, - when at least the PCM is capable of acting as a thermochromic or fluorochromic promoter (bl) or the dye is capable of changing its color or luminescent properties when the PCM changes between solid and liquid state (cl), the photo-induced thermochromic or thermoluminescent composition optionally comprises (d) one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; or

[0293] - A photo-induced thermochromic or thermoluminescent self-supporting film comprising the photo-induced thermochromic or thermoluminescent composition, one or more polymers and optionally one or more excipients; or

[0294] - A photo-induced thermochromic or thermoluminescent article comprising the photo-induced thermochromic or thermoluminescent composition or the self-supporting film.

[0295] In one embodiment, the transparent photo-induced thermochromic or thermoluminescent composition can be used to prepare a transparent film for optical filters or to prepare smart glasses, such as smart glasses, car glasses, facility / building windows, mirrors, etc. It can also be used to detect NIR radiation. In one embodiment, the light-induced thermochromic or thermoluminescent composition can be part of an optical (medical) device forming an artificial iris. Examples of optical medical devices include ocular prostheses and soft contact lenses. General procedure 1 General procedure 2

[0296] The use of the composition, the self-supporting film and the article of the application in anti-counterfeiting technology is also part of the application. The fifth aspect of the application relates to the use of:

[0297] - a photo-induced thermochromic or thermoluminescent composition comprising: a) nanoparticles, in particular metallic gold nanoparticles, capable of absorbing near infrared radiation (NIR) and converting said NIR radiation into heat; b) one or more phase change materials (PCM) selected from: bl) PCMs capable of acting as chromic or fluorochromic promoters; and b2) PCMs incapable of acting as chromic or fluorochromic promoters; c) one or more dyes selected from: cl) dyes capable of changing their color or luminescent properties when said PCMs change between solid and liquid state; and c2) dyes incapable of changing their color or luminescent properties when said PCMs change between solid and liquid state;

[0298] wherein: - when said PCMs are incapable of acting as chromic or fluorochromic promoters (b2), and said dyes are incapable of changing their color or luminescent properties when said PCMs change between solid and liquid state (c2), said photo-induced thermochromic or thermoluminescent composition further comprises one or more chromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; or, - when at least said PCMs are capable of acting as chromic or fluorochromic promoters (bl) or said dyes are capable of changing their color or luminescent properties when said PCMs change between solid and liquid state (cl), said photo-induced thermochromic or thermoluminescent composition optionally comprises (d) one or more chromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; or

[0299] - a photo-induced thermochromic or thermoluminescent self-supporting film comprising said photo-induced thermochromic or thermoluminescent composition, one or more polymers and optionally one or more excipients; or

[0300] - a photo-induced thermochromic or thermoluminescent article comprising said photo-induced thermochromic or thermoluminescent composition or said self-supporting film. In particular, said photo-induced thermochromic or thermoluminescent composition can be used in smart labels for high value product packaging, invisible watermarks for official documents and invisible labels readable by NIR.

[0301] The above is disclosed for all embodiments of the photo-induced thermochromic or thermoluminescent compositions, the self-supporting films and articles of the present invention, also applies to the use in therapy, cosmetics, diagnostics, optical devices and anti-counterfeiting technology.

[0302] Throughout the description and claims, the word "comprise" and variations of the word, such as "comprising" and "comprises," are not intended to exclude other technical features, additives, components, or steps. Furthermore, the word "comprise" encompasses the case of "consisting of. Other objects, advantages and features of the present application will become more apparent from the following description, when read in conjunction with the accompanying drawings, or can be learned by practice of the application. The following examples are provided by way of illustration and are not intended to limit the present application. Furthermore, the present application encompasses all possible combinations of particular and preferred embodiments described herein.

[0303] Examples

[0304] Abbreviations:

[0305] ACQ: Aggregation-Caused Quenching

[0306] AIE: Aggregation-Induced Emission

[0307] APTES: 3-(Aminopropyl)triethoxysilane

[0308] AuNS: Gold Nanoshell

[0309] AuNR: Gold Nanorod

[0310] BA: Bisphenol A

[0311] CV: Crystal Violet Lactone

[0312] DA: Dodecanoic Acid

[0313] DCA: 9,10-Dicyanoanthracene

[0314] DMA: N,N-Dimethylaniline

[0315] EC: Eicosane

[0316] HD: 1-Hexadecanol

[0317] MC: Microcapsule

[0318] MNP: Metal Nanoparticle

[0319] MS: Methyl Stearate

[0320] nanoSLP: Solid Lipid Nanoparticle

[0321] NIAD-4: {[5'-(p-Hydroxyphenyl)-2,2'-Bithiophen-5-yl]-Methylene}-Malononitrile

[0322] NIR: near infrared radiation

[0323] NP: nanoparticle

[0324] OC: octacosane

[0325] ODA: 1-octadecylamine

[0326] PCM: phase change material

[0327] PDI: perylene diimide

[0328] PES: polyether sulfone

[0329] PR: Prussian red

[0330] PS: polystyrene

[0331] PTDI: N,N'-di(sec-butyl)-1,6,7,12-tetra-(4-tert-butylphenoxy)perylene- 3,4:9,10-tetracarboxylic diimide

[0332] PVA: polyvinyl alcohol

[0333] RhB: rhodamine B

[0334] RT: room temperature

[0335] SA: stearic acid

[0336] SiMC: silica microcapsule

[0337] SLP: solid lipid particle

[0338] TD: 1-tetradecanol

[0339] T g : glass transition temperature

[0340] T m : melting point temperature

[0341] T m : melting point temperature of X PCM

[0342] TPE: tetraphenyl ethylene

[0343] UV: ultraviolet

[0344] General considerations

[0345] For all the examples of the present invention involving fluorescence changes, the emission spectra were recorded by a PTI Quantamaster fluorometer or by a custom-made fluorescence spectrometer in which an Andor ICCD camera is coupled to the spectrometer. Either UV light (355 nm) or visible light (450 nm) was used to excite the fluorescent agent to observe its fluorescence. The sample temperature was controlled by changing the temperature of the sample holder. In temperature-dependent fluorescence measurements, the sample was illuminated with the appropriate excitation wavelength while it was kept above or below the T m NIR irradiation was performed using a NIR laser (λ 激发 = 830 nm, 150 mW, beam diameter = 3 mm). For NIR-dependent fluorescence measurements, the sample was illuminated simultaneously with NIR irradiation and UV / Vis light appropriate for fluorescence activation. Time-dependent fluorescence experiments were performed by measuring the fluorescence at the maximum emission wavelength of the dye before, during (until steady state is reached) and after stopping the NIR irradiation.

[0346] The measurement of the fluorescence variation was performed using the following equation:

[0347]

[0348] where FIirradiation and FIdark are the fluorescence emission intensities (calculated by mathematical integration of the emission band) under NIR irradiation and without NIR irradiation, respectively.

[0349] For all the examples of the present invention involving color-changing samples, they were characterized by measuring the reflectance spectra of the films / papers. Temperature-dependent experiments were performed to determine the reflectance spectra below and above the T m of the used PCM. The effect of NIR irradiation on the color change was monitored by measuring the reflectance at the λ 最大 of the dye (in the visible region) before and after NIR irradiation. Time-dependent reflectance experiments were performed by measuring the reflectance at the maximum absorption of the dye before, during (until steady state is reached) and after stopping the NIR irradiation.

[0350] The measurement of the color variation of the films or papers when using gold nanoparticles was performed using the following equation:

[0351]

[0352] where F(R)irradiation and F(R)dark are the diffuse reflectance intensities (converted to F(R) values by the Kubelka-Munk equation) under NIR irradiation and without NIR irradiation, respectively. F(R)AuNP is the diffuse reflectance intensity provided by the AuNPs (i.e. AuNRs or AuNSs).

[0353] Gold nanoparticles (AuNPs)

[0354] Gold nanoparticles (AuNS) in the form of nanoshells

[0355] 1. Substrate / coating / film incorporating a photo-induced thermoluminescent composition

[0356] 1.1. Preparation of gold nanoparticles (AuNS) in the form of nanoshells

[0357] AuNS were prepared by mixing 10 μL of APTES with 4.60 mL of water under stirring (530 rpm) for 10-20 seconds. Then 320 μL of a 40 mM aqueous solution of HAuCl4was added, obtaining a yellow emulsion due to the poor solubility of APTES in water. The HAuCl4 / APTES mixture was stirred for 30 seconds, then 400 μL of a 0.1 M aqueous suspension of NaBH4was added. After the addition of NaBH4, the colour of the mixture turned dark green and 400 μL of a 0.1 M aqueous solution of bovine serum albumin was added to stabilise the AuNS.

[0358] 1.2. Composition

[0359] The composition of the substrates / coatings / films (Examples 1-15) incorporating the photo-induced thermoluminescent composition of the present application is disclosed in the following table.

[0360] Table 1 discloses the type of substrate, PCM and fluorescent agent forming part of the photo-induced thermoluminescent substrates / coatings / films (Examples 1-15) of the present application.

[0361] Table 1

[0362]

[0363]

[0364] (a) The paper substrate was a piece of 3 x 1 cm 2 of paper

[0365] (b) DA corresponds to the fluorescent activator dodecanoic acid

[0366] (c) The concentration is expressed as mg / mL PCM

[0367] (d) ODA corresponds to octadecylamine, which is both a PCM and a fluorescent quencher

[0368] (e) The PVA film of Example 12 was a transparent PVA film

[0369] (f) The film size was an area of 3 x 2 cm 2

[0370] (g) The film size was 19.6 cm​2 Area of (circle)

[0371] (h) The paper substrate is a piece of 1 x 1 cm 2 paper

[0372] 1.3. Preparation method

[0373] For the paper integrated with the light-induced thermoluminescence composition of the present invention

[0374] For self-supporting films made of a polymer matrix embedding a light-induced thermoluminescent composition: General procedure 3

[0375] Example 1 : An aqueous solution of AuNS (0.34 mg / mL) was dropped on a piece of cellulose paper (3 x 1 cm 2 ) avoiding water to leak on the substrate. After the water evaporation, a melted solution of RhB (20 mg / mL) in TD (0.05 g) (PCM, T m = 38 °C) was dropped on the active paper covering the entire surface. During the addition, the paper was kept above T m TD (by using a hot plate) to avoid the fast solidification of the PCM and to allow its diffusion through the pores of the paper. The final material contained AuNS and TD / RhB solution (15 mg) homogeneously distributed in the entire paper piece. As a control experiment, a paper without AuNS was prepared using the same protocol.

[0376] The paper integrated with the light-induced thermoluminescence composition of the present invention of Examples 2, 3, 4, 5, 6 and 7 was prepared following the general procedure defined above for Example 1, but using the components specified in Table 1.

[0377] SLP preparation

[0378] Example 8: The paper integrated with the light-induced thermoluminescence composition of Example 8 was prepared following the general procedure of Example 1, but RhB was replaced by a mixture of PTDI (0.11 mg / mL in TD) and DMA (7.6 mg / mL in TD). The final material contained AuNS and TD / DMA / PTDI solution (16 mg) homogeneously distributed in the entire paper surface. As a control experiment, a paper without AuNS was prepared using the same protocol.

[0379] The paper integrated with the light-induced thermoluminescence composition of the present invention of Example 9 was prepared following the general procedure 2 defined above for Example 8, but using the components specified in Table 1.

[0380] Film preparation

[0381] Example 10: The film is made of a polymer matrix (PVA) embedding SLPs of the photoinduced thermoluminescent composition (TPE@EC) of Example 4.

[0382] 1) General procedure 4 : SLPs are prepared by emulsion cooling method. First, the molten (>T m EC The TPE@EC solution (3.9 mg / mL or 1 mM, 0.65 mL or 0.5 g) at 60 °C is mixed with a preheated (>T m EC The aqueous phase (20 mL) containing the surfactant PVA (200 mg / mL) at 60 °C is mixed with the TPE@EC solution (3.9 mg / mL or 1 mM, 0.65 mL or 0.5 g) and emulsified by high shear homogenization (3000 rpm, 5 min, 60 °C). TPE@EC microdroplets (15-20 pm) are obtained. After preparation of the emulsion, it is quickly transferred into an aqueous solution (30 mL) pre-cooled in an ice bath. The PCM quickly solidifies to obtain TPE@EC SLPs. The SLPs are separated from water by flocculation and washed 2 times by decantation with clean cold water (30 mL). The SLPs are then isolated by lyophilization after freezing the suspension.

[0383] 2) NanoSLP preparation : The SLPs obtained in the previous step (150 mg) are dispersed in an aqueous solution of PVA 4-88 (20 wt.%) (1 mL) and 0.25 mL of the previously prepared AuNS suspension (0.34 mg / mL). The mixture is homogenized by vortexing while mixing and casted on a substrate (surface 3 x 2 cm 2 ) at room temperature for 48 h. Control films without AuNS are obtained using the same procedure but without adding AuNS.

[0384] The photoinduced thermoluminescent coating substrates of Example 11 of the present application are prepared following the general procedure 3 defined above for Example 10, but using the corresponding components specified in Table 1.

[0385] Film preparation

[0386] Example 12: The film is made of a polymer matrix (PVA) embedding nano-SLPs of the mixture (TPE@OC) of Example 5. Due to the small size of the SLPs, the film is transparent.

[0387] 1) General procedure 5 : nanoSLPs are prepared by emulsion cooling method. First, the molten (>T m OCTPE@OC solution (4 mg / mL or 10 mM, 1.27 mL or 1.00 g) with pre-cooled (> T m OC aqueous phase (10 mL) and emulsified by ultrasonication homogenization (Branson Ultrasonicator, 100% amplitude, 2 min) to obtain TPE@OC nanodroplets (50-400 nm). After the emulsion was prepared, it was quickly transferred to an aqueous solution (20 mL) pre-cooled in an ice bath. The PCM quickly solidified to obtain TPE@EC SLP.

[0388] 2) Microcapsule preparation The obtained suspension (0.05 mL, SLP concentration = 33 mg / mL) was diluted with an aqueous solution of PVA 4-88 (20 wt.%) (1 mL) and 0.25 mL of previously prepared AuNS (0.34 mg / mL), stirred homogeneously, and cast on a substrate / mold. The water was evaporated at room temperature for 48 h, and then a PVA film embedding SLP and AuNS was obtained. A control film without AuNS was obtained using the same procedure, but without adding AuNS.

[0389] Film preparation

[0390] Example 13: The film was made from a polymer matrix (PVA) embedding the mixture TPE@MS in PE@MS_SiMC.

[0391] 1) General procedure 6 The SiMC of TPE@MS was prepared by phase separation / shell formation. A solution of hydroxyl silicate pre-polymer (1 g), TPE (1.5 mg), and MS (300 mg) in EtOH (0.25 mL) was prepared by stirring the mixture at 40 °C. After obtaining a homogeneous solution, it was mixed with water at 40 °C and emulsified by high shear homogenization (6000 rpm) for 20 min. Then 1 mL of aqueous NH3 (25%) was added and the solution was gently stirred (1000 rpm, magnetic stirring) for 10 min. Then the solution was left without stirring for 1 h, the capsules were collected by sedimentation and washed with water. Finally, the capsules were dried at room temperature for 12-24 h.

[0392] 2) PS NP preparation ​The obtained microcapsules were mixed with an aqueous solution of PVA 4-88 (20 wt.%) (3.3 mL) and 0.83 mL of the previously prepared AuNS suspension (0.34 mg / mL), stirred homogeneously and cast on a substrate / mould. Water was evaporated at room temperature for 24-48 h, then PVA films embedding SiMC and AuNS were obtained. Control films without AuNS were obtained using the same procedure, but without the addition of AuNS.

[0393] For paper integrating light-induced irreversible thermoluminescent composition

[0394] Paper preparation

[0395] Example 14: The paper comprises PS nanoparticles containing DA and RhB.

[0396] 1) For paper integrating a light-induced thermochromic composition : PS (0.5 g), DA (50 mg) and RhB base (10.2 wt.% with respect to polymer) were dissolved in dichloromethane (5 mL) under magnetic stirring. After dissolution of all components, the final organic mixture was subsequently added to the previously prepared aqueous solution of SDS (10 mL, 0.5 wt.%). The mixture was pre-emulsified at RT (T18 IKA, 1000 rpm) for 60 min. The pre-emulsion formed was sonicated for 120 s (Branson Ultrasonic sonicator, 70% amplitude, pulse on 30 s, pulse off 10 s) to produce a nanoemulsion. The obtained mixture was transferred into a small tube and the organic solvent was evaporated at RT overnight, inducing the precipitation of the polymer and the encapsulation of the dyes and the fluorescence developer in the NPs.

[0397] 2) General procedure 7 : The PS NP powder was dispersed in water containing AuNS (0.024 mg / ml) (60 mg / ml) and dropped (0.25 ml) on the surface of a paper (1 x 1 cm 2 ) obtaining a homogeneous distribution of NPs (15 mg / cm 2 ) and AuNS. As a control experiment, a paper without AuNS was prepared using the same protocol.

[0398] The light-induced thermoluminescent coating substrate of Example 15 of the present application was prepared following the general procedure 6 defined above for Example 14, but using the components specified in Table 1.

[0399] 1.4. Results

[0400] The effect of fluorescence changes on the photoinduced thermoluminescent compositions of the present invention (Examples 1-15) after irradiation with NIR radiation at wavelengths from 600 nm to 1200 nm is shown in Tables 2 and 3 below. The fluorescence was measured by irradiating the compositions near their respective maximum absorption peaks.

[0401] Tables 2 and 3 show the effects of NIR irradiation on fluorescence activation (off / on examples) and quenching (on / off examples), as well as the reversibility of these effects.

[0402] Table 2

[0403]

[0404] (a) NIR laser irradiation: λ 激发 =830nm, power =150mW, beam diameter: 3mm; (b) materials (paper or film) prepared as described in the reported examples but without AuNS, under heating (above Tm of PCM). m Or, for Examples 14 and 15, a T higher than that of the polymer. g (c) The time required for the material to reach i) half of the initial luminescence intensity (for the on / off system) or ii) half of the luminescence intensity achievable in the steady state (for the off / on system) in the light; (d) The time required for the material to reach i) half of the final luminescence intensity (for the on / off system) in the dark (without NIR irradiation) or ii) half of the luminescence intensity achievable in the steady state (for the off / on system) before stopping NIR irradiation.

[0405] Table 3

[0406]

[0407]

[0408] 2. Substrate / coating / film integrating a photo-induced thermochromic coating substrate composition

[0409] 2.1. Composition

[0410] The composition of the photoinduced thermochromic coating substrate of the present invention (Examples 16-25) is disclosed in Table 4.

[0411] Table 4 discloses the types of substrates, PCMs, and dyes that form part of the photoinduced thermochromic coating substrates of the present invention (Examples 16-25). Table 4 also discloses the presence of PCM structures.

[0412] Table 4

[0413]

[0414]

[0415] (a) Paper substrate is a piece of 3 x 1 cm 2 paper

[0416] (b) Concentration of TD is expressed in weight percent

[0417] (c) Concentration is expressed in mg / mL PCM

[0418] (d) PVA matrix has an area of 19.6 cm 2

[0419] (e) PVA matrix has an area of 3 x 2 cm 2

[0420] (f) Commercially available; composition not specified

[0421] 2.2. Preparation methods

[0422] General procedure 8

[0423] Microcapsule preparation

[0424] Example 16: Paper integrating light-induced thermochromic composition of Example 16 was prepared following the general procedure 1 as defined above for Example 1. After evaporation of water, a melted solution (0.05 g) of BA (47 mg / mL) and CV (12 mg / mL) in TD (T m = 38 °C) was dropped on the active paper covering the entire surface. The final material contained AuNS and TD / BA / CV solution (23 mg) homogeneously distributed on the entire paper surface. As a control experiment, a paper without AuNS was prepared using the same protocol.

[0425] Paper preparation

[0426] Example 17:

[0427] - General procedure 9 PES MC of (BA + CV)@TD was prepared by phase separation / solvent evaporation. A solution of PES (250 mg), CV (7 mg), BA (28 mg) and TD (500 mg) in CHCI3(5 mL) was prepared by stirring the mixture at room temperature. After obtaining a homogeneous solution, it was mixed with an aqueous solution of surfactant (PVA, 200 mg / mL) and emulsified by high shear homogenization (5000 rpm) for 15 min. After this time, CHCI3was evaporated in a rotary evaporator, obtaining PES MC (15-20 pm). ​​​

[0428] - Microcapsule preparation AuNS were deposited on a piece of paper (3x1 cm 2 ) onto the previous cellulose paper. As a control experiment, papers without AuNS were prepared using the same protocol.

[0429] The photo-induced thermochromic coating substrates of Examples 18, 19 and 20 of the present application were prepared in accordance with the general procedure 8 defined above for Example 17, but using the components specified in Table 4.

[0430] For self-supporting films made of a polymeric matrix embedding a photo-induced thermochromic composition

[0431] Film preparation

[0432] Example 21 :

[0433] - General procedure 10 PES MC were prepared following the procedure disclosed in general procedure 8 for Example 17.

[0434] - General procedure 11 The obtained [CV+BA]@TD@PES_MC suspension (75 mg MC / mL) was mixed with an aqueous solution of PVA 4-88 (20 wt.%) (3.3 mL) and 0.83 mL of the previously prepared stock AuNS suspension (0.34 mg / mL), stirred homogeneously and cast on a substrate / mold. The water was allowed to evaporate at room temperature for 24-48 h, and a PVA film embedding MC and AuNS was obtained. A control film without AuNS was obtained using the same procedure, but without the addition of AuNS.

[0435] The photo-induced thermochromic coatings / films of Examples 22, 23, 24 and 25 of the present application were prepared in accordance with the general procedure 9 defined above for Example 21, but using the components specified in Table 4.

[0436] 2.3. Results

[0437] The influence of the color change of the photo-induced thermochromic compositions of the present application (Examples 16-25) upon irradiation with infrared light having a wavelength of 600 nm to 1200 nm is shown in Tables 5 and 6 below.

[0438] Tables 5 and 6 show the influence on the appearance (on / off examples) and disappearance (off / on) of color upon NIR irradiation and the reversibility of said influence.

[0439] Table 5

[0440] Table 5

[0441] (a) NIR laser irradiation: λ 激发 =830nm, power =150mW, beam diameter: 3mm; (b) materials (paper or film) prepared as described in the reported examples but without AuNS, under heating (above Tm of PCM). m (c) The NIR irradiation time required for the material to reach i) half of the initial color intensity (for the on / off system) or ii) half of the color intensity achievable in light-steady state (for the off / on system); (d) The time required for the material to reach i) half of the final color intensity (for the on / off system) or ii) half of the color intensity achievable in light-steady state before stopping NIR irradiation (for the off / on system) in the dark (without NIR irradiation); (e) The known presence of T in the capsule fluorescence, although the composition is not specified. m PCM at around 40 (BT40) and 65 (LT65).

[0442] Table 6

[0443]

[0444]

[0445] The results disclosed above show that the photoinduced thermochromic or thermoluminescent composition can be used to prepare photoinduced thermochromic or thermoluminescent coating substrates with improved thermochromic and thermoluminescent behavior. Specifically, it has been demonstrated that irradiating the composition of the present invention, comprising photothermal metal nanoparticles capable of selectively absorbing light with wavelengths from 600 nm to 1200 nm, one or more PCMs, and one or more dyes or one or more phosphors, with low power density and low energy radiation allows for rapid, uniform, and intense color or fluorescence changes without compromising the feasibility and reversibility of the smart material.

[0446] Gold nanoparticles in nanorod form (AuNR)

[0447] 3. Substrates / coatings / films integrating photo-induced thermoluminescence compositions

[0448] 3.1. Preparation of gold nanoparticles (AuNR) in nanorod form

[0449] AuNR (diameter 9-15nm, length 55-65nm, dispersed in water, maximum absorption peak at 850nm, positively charged) was purchased from Alfa Aesar.

[0450] 3.2. Composition

[0451] The composition of the substrates / coatings of the application integrating light-induced thermochromic compositions containing AuNRs (Examples 26-27) is disclosed in Table 7 below.

[0452] Table 7

[0453]

[0454]

[0455] (a) The paper substrate was a piece of 3 x 1 cm 2 of paper

[0456] (b) The concentration is expressed as mg / mL PCM

[0457] 3.3. Preparation method

[0458] For papers integrating light-induced thermochromic compositions

[0459] ​

[0460] Example 26: The paper of Example 26 integrating light-induced thermochromic compositions was prepared following the general procedure of Example 1, but AuNS were replaced by AuNRs. The final material contained AuNRs and TD / RhB solution (15 mg) homogeneously distributed throughout the paper piece. As a control experiment, a paper without AuNRs was prepared using the same protocol.

[0461] ​

[0462] Example 27: The paper of Example 27 integrating light-induced thermochromic compositions was prepared following the general procedure 10 defined for Example 26, but RhB was replaced by BA (47 mg / mL) and CV (12 mg / mL). The final material contained AuNRs and TD / BA / CV solution (23 mg) homogeneously distributed throughout the paper surface. As a control experiment, a paper without AuNRs was prepared using the same protocol.

[0463] 3.4. Results

[0464] The effect of the fluorescence change upon irradiation of the light-induced thermochromic compositions of the application (Example 26) with NIR radiation having a wavelength of 600 nm to 1200 nm and the effect of the color change upon irradiation of the light-induced thermochromic compositions of the application (Example 27) with said radiation are shown in Tables 8 and 9 below.

[0465] Tables 8 and 9 show the effect on the appearance of fluorescence (off / on, Example 26) and the disappearance of color (on / off, Example 27) upon NIR irradiation and the reversibility of said effects.

[0466] Table 8

[0467]

[0468] (a) NIR laser irradiation: λ = 830 nm, power = 150 mW, beam diameter: 3 mm; 激发

[0469] (b) AF and AF(R) obtained after heating (above the T m ) of the material (paper) prepared as described in the reported examples but without AuNRs;

[0470] (c) Time of NIR irradiation required for the material to reach i) half of the initial luminescence / color intensity (for on / off systems) or ii) half of the luminescence / color intensity achievable in the light steady state (for off / on systems);

[0471] (d) Time required for the material in the dark (without NIR irradiation) to reach i) half of the final luminescence / color intensity (for on / off systems) or ii) half of the luminescence / color intensity reached in the light steady state before stopping the NIR irradiation (for off / on systems).

[0472] Table 9

[0473]

[0474]

[0475] For the sake of completeness, the various different aspects of the present application are set out in the following numbered clauses:

[0476] Clause 1. A photo-induced thermochromic or thermoluminescent composition comprising:

[0477] a) nanoparticles capable of absorbing near-infrared radiation (NIR) and converting said NIR radiation into heat;

[0478] b) one or more phase change materials (PCMs) selected from:

[0479] b1) PCMs capable of acting as chromic or fluorochromic promoters; and

[0480] b2) PCMs incapable of acting as chromic or fluorochromic promoters;

[0481] c) one or more dyes selected from:

[0482] c1) dyes capable of changing their color or luminescence properties when said PCMs change between solid and liquid state; and

[0483] ​c2) a dye which is not able to change its colour or luminescence properties when the PCM changes between the solid and the liquid state;

[0484] wherein:

[0485] - when the PCM is not able to act as a colour- or fluorescence colour- change promoter (b2) and the dye is not able to change its colour or luminescence properties when the PCM changes between the solid and the liquid state (c2), the photo-induced thermochromic or thermoluminescent composition further comprises one or more colour- or fluorescence colour- change promoters selected from colour developers, luminescence quenchers and luminescence activators;

[0486] or

[0487] - when at least the PCM is able to act as a colour- or fluorescence colour- change promoter (b1) or the dye is able to change its colour or luminescence properties when the PCM changes between the solid and the liquid state (c1), the photo-induced thermochromic or thermoluminescent composition optionally comprises (d) one or more colour- or fluorescence colour- change promoters selected from colour developers, luminescence quenchers and luminescence activators.

[0488] Item 2. The composition according to item 1, which is selected from:

[0489] a) nanoparticles able to absorb NIR radiation and to convert said NIR radiation into heat;

[0490] b) one or more PCMs (PCM) able to act as colour- or fluorescence colour- change promoters (b1);

[0491] c) one or more dyes which are not able to change their colour or luminescence properties when the PCM changes between the solid and the liquid state (c2); and

[0492] optionally d) one or more colour- or fluorescence colour- change promoters selected from colour developers, luminescence quenchers and luminescence activators;

[0493] a) nanoparticles able to absorb NIR radiation and to convert said NIR radiation into heat;

[0494] b) one or more PCMs (PCM) not able to act as colour- or fluorescence colour- change promoters (b2);

[0495] c) one or more dyes able to change their colour or luminescence properties when the PCM changes between the solid and the liquid state (c1); and

[0496] optionally d) one or more colour- or fluorescence colour- change promoters selected from colour developers, luminescence quenchers and luminescence activators;

[0497] a) nanoparticles able to absorb NIR radiation and to convert said NIR radiation into heat;

[0498] b) one or more PCMs (PCMs) (bl) capable of acting as a color change or fluorescence color change promoter;

[0499] c) one or more dyes (cl) capable of changing their color or luminescence properties when the PCMs change between the solid and liquid state; and

[0500] optionally d) one or more color change or fluorescence color change promoters selected from the group consisting of color developers, luminescence quenchers and luminescence activators;

[0501] and

[0502] a) nanoparticles capable of absorbing NIR radiation and converting the NIR radiation into heat;

[0503] b) one or more PCMs (PCMs) (b2) incapable of acting as a color change or fluorescence color change promoter;

[0504] c) one or more dyes (c2) incapable of changing their color or luminescence properties when the PCMs change between the solid and liquid state; and

[0505] d) one or more color change or fluorescence color change promoters selected from the group consisting of color developers, luminescence quenchers and luminescence activators.

[0506] Clause 3. The composition according to any one of clauses 1 or 2, wherein the nanoparticles (a) are capable of absorbing NIR radiation from 600 nm to 2200 nm.

[0507] Clause 4. The composition according to any one of clauses 1-3, wherein the nanoparticles (a) are metal nanoparticles.

[0508] Clause 5. The composition according to clause 4, wherein the metal nanoparticles have a particle size from 5 to 500 nm.

[0509] Clause 6. The composition according to any one of clauses 4 or 5, wherein the amount of metal nanoparticles is from 0.00005 to 0.5 mg / mg PCM.

[0510] Clause 7. The composition according to any one of clauses 4-6, wherein the metal nanoparticles are in a form selected from the group consisting of nanospheres, nanostars, nanodumbells, nanotubes, nanoshells, nanorods, nanocages, nanohemispheres, nanodomes and nanopyramids.

[0511] Clause 8. The composition according to any one of clauses 4-7, wherein the metal of the metal nanoparticles is selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, alloys thereof, oxides thereof and mixtures thereof.

[0512] Item 9. The composition according to any one of items 1-8, wherein:

[0513] - the PCM is a PCM (bl) capable of acting as a color change or fluorescence color change promoter selected from acid-containing compounds, amine-containing compounds, sulfur-containing compounds, alcohol-containing compounds, and mixtures thereof;

[0514] or

[0515] - the PCM is a PCM (b2) incapable of acting as a color change or fluorescence color change promoter selected from (C8-C 52 )alkane-based PCMs, (C 14 -C 50 )alkene-based PCMs, (C 14 -C 50 )alkyne-based PCMs, and mixtures thereof.

[0516] Item 10. The composition according to any one of items 1-9, wherein:

[0517] - the dye is a dye (cl) capable of changing its color or luminescence properties when the PCM changes between solid and liquid state selected from dyes that change their color and / or luminescence properties according to aggregation / neighborhood state, temperature sensitive dyes, and dyes that change their color and / or luminescence properties according to medium viscosity / stiffness;

[0518] or

[0519] - the dye is a dye (c2) incapable of changing its color or luminescence properties when the PCM changes between solid and liquid state selected from charge transfer dyes (oxido-reduction dyes), pH responsive dyes, polarity dependent dyes, pH sensitive luminescent dyes, and oxido-reduction luminescent agents.

[0520] Item 11. The composition according to any one of items 1-10, wherein:

[0521] the color change or fluorescence color change promoter is a color developer selected from acids, bases, hydrogen-bonding compounds, electron transfer compounds, and mixtures thereof; or

[0522] the color change or fluorescence color change promoter is a luminescence quencher selected from resonance energy transfer quenchers, triplet state quenchers, electron transfer quenchers, and mixtures thereof; or

[0523] the color change or fluorescence color change promoter is a luminescence activator selected from singlet, triplet sensitizers, fluorescence resonance energy transfer sensitizers, and electron transfer sensitizers, and mixtures thereof.

[0524] Item 12. The composition according to any one of items 1-11, further comprising one or more additional components selected from the group consisting of a pharmaceutically active ingredient and a reactive oxygen species.

[0525] Item 13. A light-induced thermochromic or thermoluminescent self-supporting film comprising the light-induced thermochromic or thermoluminescent composition as defined in any one of items 1-12, one or more polymers and optionally one or more excipients.

[0526] Item 14. A light-induced thermochromic or thermoluminescent article comprising the composition as defined in any one of items 1-12 or the self-supporting film as defined in item 13.

[0527] Item 15. The article according to item 14, selected from the group consisting of:

[0528] (A) A light-induced thermochromic or thermoluminescent coating article comprising:

[0529] a substrate; and

[0530] a light-induced thermochromic or thermoluminescent coating deposited on the surface of the substrate,

[0531] wherein the coating comprises the composition as defined in any one of items 1-12 and optionally one or more polymers.

[0532] (B) A light-induced thermochromic or thermoluminescent embedding article comprising:

[0533] a porous substrate;

[0534] a light-induced thermochromic or thermoluminescent composition as defined in any one of items 1-12 embedded in the porous substrate; and

[0535] optionally one or more additional external coatings.

[0536] and

[0537] (C) An article containing a light-induced thermochromic or thermoluminescent self-supporting film comprising one or more light-induced thermochromic or thermoluminescent self-supporting films as defined in item 13.

Claims

1. A photo-induced thermochromic or thermoluminescent composition suitable for use in anti-counterfeiting technology or optical devices, said composition comprising: a) nanoparticles capable of absorbing near infrared radiation (NIR) and converting said NIR radiation into heat; b) one or more phase change materials (PCM) selected from: bl) a PCM capable of acting as a thermochromic or fluorochromic promoter; and b2) a PCM not capable of acting as a thermochromic or fluorochromic promoter; c) one or more dyes selected from: cl) a dye capable of changing its color or luminescence properties when said PCM changes between solid and liquid state; and c2) a dye not capable of changing its color or luminescence properties when said PCM changes between solid and liquid state; wherein: - when said PCM is not capable of acting as a thermochromic or fluorochromic promoter (b2), and said dye is not capable of changing its color or luminescence properties when said PCM changes between solid and liquid state (c2), said photo-induced thermochromic or thermoluminescent composition further comprises one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; or - when at least said PCM is capable of acting as a thermochromic or fluorochromic promoter (bl) or said dye is capable of changing its color or luminescence properties when said PCM changes between solid and liquid state (cl), said photo-induced thermochromic or thermoluminescent composition optionally comprises (d) one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; is a photo-induced thermochromic or thermoluminescent composition selected from: a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat; b) one or more PCMs capable of acting as a thermochromic or fluorochromic promoter (bl); c) one or more dyes not capable of changing its color or luminescence properties when said PCM changes between solid and liquid state (c2); and optional d) one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat; b) one or more PCMs not capable of acting as a thermochromic or fluorochromic promoter (b2); c) one or more dyes capable of changing its color or luminescence properties when said PCM changes between solid and liquid state (cl); and optional d) one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat; b) one or more PCMs capable of acting as a thermochromic or fluorochromic promoter (bl); c) one or more dyes capable of changing its color or luminescence properties when said PCM changes between solid and liquid state (cl); and optional d) one or more thermochromic or fluorochromic promoters selected from color developers, luminescence quenchers and luminescence activators; and a) nanoparticles capable of absorbing NIR radiation and converting said NIR radiation into heat; b) one or more PCMs (b2) that are not able to act as color change or fluorescence color change promoters; c) one or more dyes (c2) that are not able to change their color or luminescence properties when the PCM changes between the solid state and the liquid state; and d) one or more color change or fluorescence color change promoters selected from color developers, luminescence quenchers and luminescence activators; wherein the nanoparticles (a) that are able to absorb near infrared radiation (NIR) and convert the NIR radiation into heat are metal gold nanoparticles having an absorption wavelength of 600 nm to 2200 nm; the PCMs (bl) that are able to act as color change or fluorescence color change promoters are selected from the group consisting of dodecanoic acid, stearic acid, methyl palmitate, methyl stearate, methyl arachidate, 1-tetradecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-hexadecylamine, 1-octadecylamine, glyceryl trinonanoate, glyceryl trilaurate, glyceryl trimyristate, glyceryl tripalmitate and glyceryl tristearate and mixtures thereof; the PCMs (b2) that are not able to act as color change or fluorescence color change promoters are selected from the group consisting of 1-hexadecene, eicosene, 1-hexadecyne, tetradecane, pentadecane, eicosane (EC), tetracosane, hexacosane, octacosane (OC), nonacosane, triacontane, tritriacontane, tetracontane, tetraforty- four, pentacontane, pentaforty-four and mixtures thereof; the dyes (cl) that are able to change their color or luminescence properties when the PCM changes between the solid state and the liquid state are selected from the group consisting of dyes that change their color and / or luminescence properties depending on the aggregation / neighborhood state, temperature sensitive dyes and dyes that change their color and / or luminescence properties depending on the viscosity / stiffness of the medium; and the dyes (c2) that are not able to change their color or luminescence properties when the PCM changes between the solid state and the liquid state are selected from the group consisting of charge transfer dyes (redox dyes), pH responsive dyes, polarity dependent dyes, pH sensitive luminescent dyes and redox luminescent agents.

2. The composition according to claim 1, wherein the nanoparticles have a particle size of 5 to 500 nm.

3. The composition according to claim 1, wherein the nanoparticles are present in an amount of 0.00005 to 0.5 mg / mg PCM.

4. The composition according to claim 1, wherein the nanoparticles are in a form selected from the group consisting of nanospheres, nanostars, nanodumbells, nanotubes, nanoshells, nanorods, nanocages, nanohemispheres, nanodomes and nanopyramids.

5. The composition according to claim 4, wherein the nanoparticles are in a form selected from the group consisting of nanospheres, nanoshells and nanorods.

6. The composition according to claim 1, wherein: the color change or fluorescence color change promoter is a color developer selected from the group consisting of acids, bases, hydrogen bonding compounds, electron transfer compounds and mixtures thereof; or the color change or fluorescence color change promoter is a luminescence quencher selected from the group consisting of resonance energy transfer quenchers, triplet state quenchers, electron transfer quenchers and mixtures thereof; or The color change or fluorescence color change promoter is a luminescence activator selected from the group consisting of singlet, triplet sensitizers, fluorescence resonance energy transfer sensitizers, and electron transfer sensitizers, and mixtures thereof.

7. The composition of claim 1, further comprising one or more additional components selected from the group consisting of a pharmaceutically active ingredient and a reactive oxygen species.

8. A photo-induced thermochromic or thermoluminescent self-supporting film comprising the photo-induced thermochromic or thermoluminescent composition as defined in claim 1, one or more polymers and optionally one or more excipients.

9. A photo-induced thermochromic or thermoluminescent article comprising the composition as defined in claim 1 or the self-supporting film as defined in claim 8.

10. An article comprising the composition as defined in claim 1 or the self-supporting film as defined in claim 8, selected from the group consisting of: (A) a photo-induced thermochromic or thermoluminescent coating article comprising: a substrate; and a photo-induced thermochromic or thermoluminescent coating deposited on a surface of the substrate, wherein the coating comprises the composition as defined in claim 1 and optionally one or more polymers; (B) a photo-induced thermochromic or thermoluminescent embedded article comprising: a porous substrate; a photo-induced thermochromic or thermoluminescent composition as defined in claim 1 embedded in the porous substrate; and optionally one or more additional external coatings; and (C) a photo-induced thermochromic or thermoluminescent self-supporting film-containing article comprising one or more photo-induced thermochromic or thermoluminescent self-supporting films comprising the photo-induced thermochromic or thermoluminescent composition as defined in claim 1, one or more polymers and optionally one or more excipients.

11. Use of the photo-induced thermochromic or thermoluminescent composition as defined in claim 1 in an optical device.

12. Use of the photo-induced thermochromic or thermoluminescent self-supporting film as defined in claim 8 in an optical device.

13. Use of the photo-induced thermochromic or thermoluminescent article as defined in claim 9 in an optical device.

14. Use of the photo-induced thermochromic or thermoluminescent composition as defined in claim 1 for anti-counterfeiting technology.

15. Use of the photo-induced thermochromic or thermoluminescent self-supporting film as defined in claim 8 for anti-counterfeiting technology.

16. Use of the photo-induced thermochromic or thermoluminescent article as defined in claim 9 for anti-counterfeiting technology. ​

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