EP1511875A2

EP1511875A2 - Method and device for incorporating a compound in the pores of a porous material and uses thereof

Info

Publication number: EP1511875A2
Application number: EP03757115A
Authority: EP
Inventors: Thu-Hoa Tran-Thi; Thanh-Toan Truong
Original assignee: Commissariat a lEnergie Atomique CEA
Current assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 2002-06-11
Filing date: 2003-06-06
Publication date: 2005-03-09
Also published as: AU2003251111A1; JP2005529320A; AU2003251111A8; WO2003104517A2; FR2840547B1; US20060051826A1; WO2003104517A3; CN1668775A; FR2840547A1

Abstract

The invention concerns a method and device for incorporating a compound in the pores of a porous material selected among microporous and mesoporous materials obtained by sol-gel process, as well as the uses of said method and said device. The method comprises vaporization or sublimation of the compound in a chamber containing the porous material. The invention is useful for doping microporous or mesoporous materials obtained by sol-gel process and, in particular, materials mesoporous relative to structuring surfactants, for making chemical sensors and multisensors, molecular sieves, selective filtering membranes, stationary phases for chromatography, optical or optoelectronic materials.

Description

METHOD AND DEVICE FOR INCORPORATING A COMPOUND INTO PORES OF POROUS MATERIAL AND THEIR

USES

DESCRIPTION

Technical area

The present invention relates to a process for incorporating a compound into the pores of a porous material and, more specifically, to a porous material selected from microporous and mesoporous materials obtained by the sol-gel process that the In what follows, microporous and mesoporous sol-gel materials will be referred to more simply.

It also relates to a device for implementing this method.

The method according to the invention, which is applicable to both an organic and inorganic compound, leads, according to the operating conditions used, to an incorporation of this compound, either in the form of monomers or in the form of aggregates.

In what precedes and what follows, "monomer" is understood to mean an individualized molecule, while "aggregate" is understood to mean an assembly of several molecules bonded together by non-covalent bonds.

One of the objectives of the invention is the incorporation, in the form of monomers, of an organic compound and, more particularly of a Probe molecule - that is, a detectable molecule capable of interacting specifically with a molecular species and revealing its presence and, optionally, concentration within a complex mixture - in the pores a microporous or mesoporous sol-gel material and, in particular, a mesoporous material with structuring surfactants.

A microporous or mesoporous material thus "doped" by a probe molecule finds an application in the manufacture of chemical sensors and multisensors and, more specifically, of sensors and multisensors for the detection and dosing of atmospheric pollutants.

It can also find application in many other fields such as the manufacture of molecular sieves, selective membranes for filtration, stationary phases for chromatography, especially exclusion, or optical materials such as optical filters, or optoelectronic by exploiting the non-linear properties of a doped material.

State of the art

Schematically, the sol-gel process consists in forming a colloidal suspension of oxide particles (or "sol") by hydrolysis and condensation of a precursor or a mixture of ion precursors (salts) and / or molecular (alkoxides) to dry the soil so as to obtain a semi-rigid "gel" by complementary condensation of said or said precursors, and subjecting the gel to a heat treatment of drying and densification.

This process makes it possible to produce a wide variety of materials, in the form of solid pieces, powders, fibers or films, and in particular microporous and mesoporous thin films that can be used, after incorporation of probe molecules, of sensitive layers in sensors and multi-sensor chemicals. It is generally accepted in the field of sol-gel materials that a microporous film has pores with a diameter of less than 20 Å (Angstrδms), while a mesoporous material has pores with a diameter of 20 Å. 5 μm (microns). Mesoporous materials with structural surfactants (MTS) appeared ten years ago following the work of BECK et al. (J. Am Chem Soc, 1992, 114, 10834) [1]. These materials are obtained by polycondensing, according to the sol-gel process, networks of metal oxides (silicon alkoxides in particular) in the presence of a surfactant whose molecules form micelles organized on a nanoscopic scale.

STDs have the particularity of having a double porosity: in fact, the polycondensation of the metal oxide networks around the surfactant micelles leads to the formation of a porous inorganic material whose pores form a first unorganized porosity and which contains a compact and orderly arrangement of organic micelles; by calcination of these micelles, a second porosity appears, which is organized contrary to the previous one and whose structure depends directly on the size of the micelles and their three-dimensional arrangement. Another special feature of STMs is that they have pores with adjustable diameters. Indeed, it is possible to vary the pore diameter of the first porosity from about 5 to 18 Å, in particular by the choice of metal oxides serving as precursors during the preparation of the MTS, and to vary the pore diameter. of the second porosity of about 10 to 100Å by varying the length of the surfactant chain or using an agent capable of swelling the surfactant micelles. The characteristics of the MTS that have just been mentioned make it a particularly interesting material for the realization of sensors and multi-sensor chemicals and, in particular, sensors and multi-sensors for detecting and quantifying atmospheric pollutants.

Indeed: on the one hand, the unorganized porosity of MTS can serve as molecular sieve and promote the diffusion of small pollutants or gases whose interference we want to study; on the other hand, the pore diameter of the organized porosity can be adjusted so that, after incorporation in these pores of a probe molecule capable of interacting with a family of pollutants, the remaining space corresponds to the kinetic diameter of 'a particular pollutant of this family. Thus, the specificity of probe molecules vis-à-vis a family of pollutants, is added a specificity of the pore diameter vis-à-vis a particular pollutant of this family. This dual specificity makes it possible to avoid or, at the very least, limit the risks of interference between pollutants of the same nature but of different size.

The incorporation of probe molecules into the pores of MTS with a view to their use as sensitive layers of chemical sensors and multi-sensors, must fulfill three main requirements:

- Probe molecules must not decompose during their incorporation or lose their reactivity to pollutants and their ability to serve as developers;

- they must not be found in the pores in the form of aggregates but only in the form of monomers, the presence of aggregates in the pores affecting both the diffusion of pollutants to the reactive sites, the reactivity of the probe molecules vis-à-vis pollutants and the properties that make them detectable; and

they must also not be found in the pores in a solvated form for identical reasons of diffusional and reactional discomfort.

These constraints also exist in the case of the incorporation of a probe molecule into the pores of a porous sol-gel material other than an MTS. So many techniques have been proposed so far to incorporate a compound into pores of a microporous or mesoporous material prepared by a process other than the sol-gel process such as, for example, liquid phase sorption, gas phase sorption, solid state sorption, exchange Ion (see Schulz-Ekloff, et al., Microporous and Mesoporous Materials, 2002, 51, 91-138, [4]), both methods for incorporating a compound into pores. microporous or mesoporous material obtained by the sol-gel process are very limited in number.

In fact, it is essentially a process of adding the compound to the soil before it condenses into a gel. These processes, which are described in particular in US Pat. Nos. 5,650,311 [2] and 5,824,526 [3], have numerous disadvantages.

Indeed, insofar as the soil comprises, as solvents, water and alcohol, they are, in the first place, unsuited to the incorporation of water-sensitive compounds due to major risk of hydrolysis of these compounds. They are also unsuited to the incorporation of hydrophobic compounds which, because of their low solubility in water and alcohol, can be incorporated only in very small quantities and will tend to form aggregates in the soil and, therefore, to find themselves in this same form in the final material. Moreover, during the gelation of the soil, the interstitial solvents gradually evaporate by taking with them molecules of the incorporated compound, thus creating a concentration gradient of this compound in the final material.

The processes described in the aforementioned US patents also pose another difficulty which is that of completely extracting the solvents present in the final material, especially when these interact with the surface of the pores, in order to prevent the compound incorporated from is present in the pores in a solvated form. Finally, they do not make it possible to control the incorporation of the compound while it is taking place and it is only after drying of the gel and evaporation of the residual solvents, that is to say when the compound incorporated in ceased to migrate to the surface of the material, it becomes possible to verify whether the incorporation proceeded satisfactorily.

The problem arises, therefore, of providing a method for incorporating a compound into the pores a microporous or mesoporous sol-gel material which:

- allows, depending on the purpose of this material, to incorporate the compound only in the form of monomers or, conversely, in the form of aggregates,

- does not use or that in a very limited way of solvent,

is not likely to cause degradation of the compound, whether by hydrolysis, thermal decomposition or otherwise, - is applicable to the greatest possible number of compounds, whether mineral or organic, hydrophobic or hydrophilic, ...,

- offers the possibility, if desired, of controlling the incorporation of the compound as it is carried out, and which moreover

- be simple to implement and at acceptable costs, both on an industrial and experimental scale. This problem is solved by the present invention which proposes a process for incorporating a compound into the pores of a porous material chosen from microporous and mesoporous sol-gel materials, as well as a device specially designed to implement this process.

Presentation of the invention

The method of incorporating a compound into the pores of a porous material according to the invention is characterized in that it comprises the vaporization or sublimation of this compound in an enclosure containing said material.

Thus, the method according to the invention is based on the use of a change in the physical state of the compound to obtain incorporation into the pores of a porous material, this change consisting either in a passage of the liquid state in the gaseous state, either in a direct passage from the solid state to the gaseous state. The temperature at which a compound vaporizes or sublimates depends on the pressure at which it is located, so that it is possible to play on the pressure to change this temperature. This is perfectly illustrated by the P / T phase diagram of a pure body. The vaporization and sublimation temperatures available in the literature correspond, in the absence of indications to the contrary, to those established at atmospheric pressure and are likely to be substantially lowered by the use of lower pressures, that is, say by the use of vacuum.

According to the invention, the conditions of temperature and pressure in which the compound is vaporized or sublimed are chosen, firstly, as a function of the thermal decomposition temperature of this compound.

Indeed, it is desirable that the temperature at which the compound is vaporized or sublimated is at least 30 ° C lower, and preferably at least 50 ° C at the temperature at which it decomposes, in order to to rule out any risk of thermal decomposition of said compound during its incorporation into the pores of the porous material. The thermal decomposition temperature of a large number of compounds is known, in which case it is generally indicated in reference works such as the MERCK INDEX, twelfth edition, or catalogs of chemical suppliers such as the ALDRICH catalog. -CHEMISTRY. When the decomposition temperature of a compound is not known, then it can be determined, for example by bringing the compound to higher and higher temperatures and monitoring the temperature at which it is consumed or at which it lose its properties, for example absorbance, fluorescence, luminescence or other.

Also, whatever the compound to be incorporated, it is possible to define, for this compound, a maximum operating temperature, this temperature being, according to the invention, lower by at least 30 ° C. and, preferably, by at least 50 ° C at the thermal decomposition temperature of said compound, depending on the margin of safety that it is desired to provide.

The conditions of temperature and pressure at which the compound is vaporized or sublimed are chosen, secondly, depending on the necessity and / or the possibility of operating at a temperature lower than that at which it vaporizes. or sublimates at atmospheric pressure, especially in view of the equipment available. Thus, for example, in the case where the compound has, at atmospheric pressure, a very high vaporization or sublimation temperature (of the order of several hundred degrees) and where one can not or one does not want to operate at this temperature, for reasons of equipment, safety or more simply operating comfort, then will operate under vacuum at a pressure to lower the vaporization or sublimation temperature of the compound to an acceptable value.

On the other hand, in the case where the compound has a large vapor pressure and is capable of vaporizing or subliming at a temperature of low or medium elevation at atmospheric pressure, it will be possible to operate at this temperature and pressure as well as a lower temperature under vacuum. Another criterion that can be taken into account for the choice of temperature and pressure conditions at which the compound is vaporized or sublimated is the rate at which it is desired to incorporate the latter into the pores of the porous material, this speed being itself even chosen according to the molecular form (monomers or aggregates) under which it is desired that the compound is present in the pores.

In fact, in order to incorporate the compound into the pores of the porous material only in the form of monomers, it is desirable to use temperature and pressure conditions that make it possible for the vaporization or sublimation to proceed very slowly. so that the diffusion of the compound inside the pores is as homogeneous as possible over the entire material.

On the other hand, when the constraint of incorporating the compound into the pores of the porous material in the form of monomers does not exist and the purpose of the vaporization or sublimation is to incorporate the greatest possible amount of in the pores, for example if this material is intended to serve as molecular sieves, then it is desirable to use conditions of temperature and pressure to allow pore filling as fast as possible.

However, for a given pressure, a compound vaporizes or sublimates the faster the temperature of the medium in which it is higher, while for a given temperature, a compound vaporizes or sublimates. as much faster than the pressure that prevails in the environment in which it is located is weaker.

Also, it is possible to modulate the rate at which a compound vaporizes or sublimates by acting on the temperature or the pressure at which this vaporization or sublimation is carried out.

According to the invention, it is attempted to operate, preferably, at a temperature as close as possible to the ambient temperature and, in any case, to a temperature which does not exceed 200 ° C.

As a result, the compound is vaporized or sublimed, preferably under vacuum, in which case the process according to the invention comprises: a) evacuation of the enclosure containing the compound and the porous material until a vacuum is obtained desired, and optionally, b) heating the enclosure to the selected temperature to vaporize or sublimate the compound. In any case, it is the temperature chosen to operate that determines whether the compound is vaporized or sublimated. Indeed, if it is, at this temperature, in a liquid form, then it is vaporized, while if it is in a solid form, for example pulverulent, or pasty, then it is sublimated.

When the compound is in the form of a paste, the invention provides for subliming it under vacuum after having separated the agglomerates by at least partial dissolution of the paste in a volatile solvent which will then be easily removed at room temperature when of the vacuum installation in the enclosure containing the compound and the porous material.

According to an advantageous arrangement of the invention, in the case where it is intended to vaporize or sublimate the compound in a vacuum, the chamber containing the compound and the porous material is cooled to a temperature of -40 ° C. or lower just before its evacuation, to prevent it causes a sudden suction and dispersion of the compound throughout the volume of the enclosure. This cooling can, for example, be obtained by immersing the enclosure in liquid nitrogen or in a bath of dry ice and ethanol. According to another advantageous arrangement of the invention, in the case where it is intended to vaporize or sublimate the compound at a temperature above room temperature, the enclosure containing the compound and the porous material is heated by immersion in a bath oil maintained at the chosen temperature to vaporize or sublimate the compound, this heating mode ensuring, in fact, a particularly homogeneous supply of heat.

However, it can also be heated by means of a hot water bath or electric heating resistors.

Whatever the mode of heating of the retained enclosure, the porous material is preferably thermally insulated from the wall and the bottom of this enclosure so that the compound in gaseous form can condense or solidify, a once in contact with the pore walls of the porous material.

The use of an oil bath is not restricted to the only case where the compound is intended to be vaporized or sublimated at a temperature above room temperature. Indeed, it can also be considered to operate at room temperature to ensure homogeneity of the temperature around the perimeter of the enclosure and the maintenance of this chamber at a constant temperature.

According to the invention, the amount of compound to vaporize or sublimate is preferably chosen according to the pore volume of the porous material and the amount of compound that is to be incorporated in the pores of this material according to its destination .

It is indeed possible to determine the optimum amount of compound to be present in the pores of the porous material depending on the use that is reserved for it. Thus, for example, in the case where it is intended to serve as a sensitive layer in a chemical sensor and where, therefore, the compound to be incorporated is a probe molecule such as a fluorophore, it is appropriate that the amount of fluorophore present in the sufficient to detect it, but not too much so that the analyte to be detected can penetrate the pores, interact with the fluorophore, and for this interaction to result in a significant variation in the fluorescence emitted by the fluorophore.

The pore volume of a porous material can be measured by low temperature gas adsorption and desorption techniques. By dividing this pore volume by the volume of a molecule of the compound to be incorporated, the maximum number of molecules of this compound that can be incorporated per unit weight of porous material is obtained. Knowing the molecular weight of the compound, it is then easy to calculate the maximum amount by weight of the compound that can be incorporated per unit weight of porous material and, therefore, to be vaporized or sublimed to saturate the pores of 1 g of material.

Once this maximum amount is known, it is then possible to determine, by some experimental tests, the amount of compound to vaporize or sublimate the most suitable to the desired result.

According to another advantageous arrangement of the invention, the method comprises one or more operations for controlling the incorporation of the compound as it is carried out. Such a provision turns out to be, in fact, very useful when it is desired to define the operating conditions (temperature, pressure and duration of the vaporization or sublimation, amount of compound to be used, ...) most suitable for the obtaining a particular result (for example, incorporation of the compound only in the form of monomers or obtaining a specific pore filling rate). It also makes it possible to verify that the incorporation of the compound is carried out correctly with respect to the desired result and, if necessary, to modify the operating conditions accordingly.

Preferably, this control is achieved by optical measurements, for example of absorbance, fluorescence, luminescence or the like.

According to the invention, the porous material is preferably in the form of a block, for example a parallelepiped block, or of one or more thin layers covering one and / or the other of the faces of an inert substrate such as a quartz blade or glass.

Alternatively, however, it is possible to implement the method of the invention with a porous powdery material. The process according to the invention has proved to be suitable both for the incorporation of compounds in the pores of inorganic materials and for those of materials or organic-inorganic hybrids, and in particular in the pores of MTS, all these materials being capable of to be based on silicon, vanadium, titanium, tin, zirconium, gallium or a mixture thereof.

The process according to the invention has many advantages. Indeed: - the vaporization or sublimation of the compound to be incorporated using no solvent, the method avoids both the compound is found in the pores in a solvated form and a concentration gradient of the compound is not establishes within the porous material;

on the contrary, it results in a very homogeneous distribution of the compound in the pores of the porous material;

it offers the possibility of incorporating the compound in a form (monomers or aggregates) and in a quantity perfectly adapted to the use for which the porous material is intended;

- it makes it possible to verify, as and when the incorporation takes place, that it satisfies the objectives that have been set and to modify, if necessary, the operating conditions accordingly;

it uses very small quantities of compound, even in the case where it is desired to saturate the pores of the porous material, so that when the vaporization or sublimation is carried out in the presence of a heat source, does not observe a temperature gradient in the chamber in which this vaporization or sublimation takes place; it is applicable to a very large number of compounds since in principle all the compounds are vaporizable or sublimable, as well as very different porous materials;

- it is simple to implement and offers, in particular, the possibility of working at reasonable temperatures; it does not require complicated and expensive equipment.

In this respect, the subject of the present invention is also a device which makes it possible to implement the method according to the invention and which comprises: an enclosure provided with an opening,

means for immobilizing at least one sample of porous material in the chamber,

means for thermally isolating this sample from the wall and the bottom of the enclosure, means for sealing the enclosure, and

- Means for connecting the enclosure to a vacuum generating system.

According to a first preferred embodiment of the device, the means for immobilizing the sample of porous material also serve as means to thermally isolate it from the wall and the bottom of the enclosure.

Preferably, these means comprise a support, for example of cylindrical, cubic or frustoconical shape, which consists of an insulating material such as teflon ^® , which is integral with the bottom of the enclosure and which is provided with means for maintaining said sample. These holding means consist, for example, in a groove passing through the face of the support opposite to that in contact with the bottom of the enclosure and in which can be inserted, or one of the ends of the sample if it is in the form of a block or one or more thin layers covering the one and / or the other of the faces of a substrate, or the base of a cup containing the sample if it is in a powder form.

The holding of the sample or the cup may be reinforced by the presence, along this groove, of one or more elastic or flexible elements.

Furthermore, in this first preferred embodiment of the device, the means for sealing the enclosure also serve as means for connecting it to the vacuum producing system such as a vacuum ramp.

Advantageously, these means comprise a shutter constituted by a first tube which is provided, at one of its ends, with means for its hermetic fixing on the enclosure and, at the other of its ends, with a vacuum valve. , and which carries laterally a second tube terminated by means for its connection to the vacuum generating system, the zone of engagement of the second tube on the first being such that the communication between these two tubes can be opened or closed by rotation of the tap empty.

Preferably, the enclosure is made of a transparent material such as quartz or glass, to allow control, by optical measurements, incorporation of the compound as it proceeds.

Advantageously, the enclosure is a four-sided optical tank. According to another preferred embodiment of the device, it further comprises means for connecting it together with at least one other device as previously defined, to a vacuum producing system. According to yet another preferred embodiment of the device, the enclosure contains a plurality of tubes adapted to each contain at least one sample of porous material, each tube being provided with means for immobilizing the sample that it contains and means for thermally isolate it from the other tubes, from the bottom of the enclosure, and, if necessary, from the wall of this enclosure.

In this last preferred embodiment of the device, the means for immobilizing the sample of porous material also serve to isolate it thermally from the bottom of the enclosure.

Preferably, these means also comprise, a support consisting of an insulating material, which is integral with the bottom of the enclosure and which is provided with means for holding said sample.

Furthermore, the means for thermally insulating the sample of porous material from the other tubes and, where appropriate, from the wall of the enclosure are constituted by the wall of the tube in which it is located, this wall being formed of a insulating material such as Teflon. In this last preferred embodiment of the device, the means for sealing the enclosure also serve as means for connecting it to the vacuum producing system and comprise, on the one hand, a cover adapted to be hermetically fixed on the enclosure, and, on the other hand, a shutter constituted by a first tube which is provided at one of its ends with means for its hermetic fixing on the lid and, at the other of its ends, with a tap. vacuum, and laterally carries a second tube terminated by means for its connection to the vacuum generating system, the area of engagement of the second tube on the first being such that the communication between these two tubes can be opened or closed by rotation of the vacuum valve.

The invention furthermore relates to the use of a method or a device as defined above, for incorporating an organic compound in the form of monomers into the pores of a porous material chosen from microporous and mesoporous materials. sol-gel and, more particularly, in the pores of a mesoporous material with structuring surfactants (MTS), all these materials being able to be based on silicon, vanadium, titanium, tin, zirconium, gallium or else a mixture of these.

Examples of MTS include those known as M41S, MCM-41, MCM-48, SBA, HMS, MSU, FSM-16, PCH and ZSM. Preferably, the porous material is in the form of a block or one or more thin layers covering one and / or the other of the faces of an inert substrate, while the compound is a suitable probe molecule. to detect and, optionally, quantify an analyte, i.e., in practice a marker or ligand coupled to a marker.

In the context of the invention, the term "marker" means a molecule endowed with a particular physical property which renders it detectable and identifiable. Furthermore, the term "ligand" means a molecule capable of interacting with an analyte by collision or by forming a complex with it by a physical or chemical bond. Thus, depending on the ability of the label to interact with the analyte, it can be used alone or conjugated to a ligand capable of interacting with said analyte.

As examples of markers that may be used in the context of the invention, mention may be made of fluorophores such as

Bodipy, 1,3-diphenyl-1,3-dipropanedione, dibenzoylmethanatobore difluoride and its derivatives

(naphthoyl-benzoyl, biphenylcarbonyl-benzoyl, biphenyl-carbonyl-naphthoyl, methoxybenzoyl-benzoyl), phenylhydrazine and its nitro and chlorinated derivatives, 0-pentafluorobenzylhydroxylamine, anthracene and its derivatives, bi-anthryl and its derivatives , pyrene and its derivatives, pyrenol, pyranine, fluoroscéine, orégon green, rhodamine and its derivatives, cyanine and its derivatives, porphyrins, phthalocyanines, porphyrazines, tetracyanoquinodimethane and its derivatives; phosphors such as luminol and luciferin; chromophores such as xanthene, anthraquinone, monoazo, diazo and triphenylmethane.

A microporous or mesoporous material obtained by the sol-gel process and whose pores contain a probe molecule in the form of monomers, is of great interest for the manufacture of chemical sensors and, a fortiori, of chemical multisensors (a multisensor consisting of a plurality of sensors) for detecting or assaying a set of analytes and, more particularly, air pollutants (CO, C0 _2, N0 _2, NO, S0 _2, CH ₂ 0 and other aldehydes, benzene, toluene, xylenes, ethylbenzene ...) or gaseous molecules used in the field of microelectronics (Cl ₂ , BCl ₃ , AlCl ₃ ....).

Thus, for example, a material containing as probe molecule, phenylhydrazine, one of its nitrous or chlorinated derivatives, or O-pentafluorobenzylhydroxylamine may be used to capture formaldehyde or other aldehydes present in gaseous form in the 'air. A material containing as probe molecule, 1,3-diphenyl-1,3-dipropanedione may be used to capture the gases BC1 ₃ and A1C1 ₃ .

A material containing, as probe molecule, dibenzoylmethanatobore difluoride or one of its derivatives (naphthoyl-benzoyl, biphenylcarbonylbenzoyl, biphenylcarbonyl-naphthoyl, methoxybenzoyl) benzoyl) can be used to capture benzene and its substituted derivatives, while a material containing as a probe molecule, a porphyrin or a metal phthalocyanine can be used to capture CO, NO and / or NO ₂ .

The invention therefore also relates to the use of a method or a device as defined above, for the manufacture of a sensor or multi-sensor chemical, including the detection or dosing of atmospheric pollutants.

In addition to the preceding provisions, the invention also comprises other provisions which will emerge from the additional description which follows, which is given for illustrative and non-limiting, with reference to the accompanying drawings.

Brief description of the drawings

Figure 1 is a schematic vertical sectional view of a device according to the invention in a first embodiment.

Figure 2 is a schematic vertical sectional view of a device according to the invention in a second embodiment. Figure 3 is a partial schematic view in vertical section of a device according to the invention in a third embodiment.

FIG. 4 is a graph illustrating the variation of the absorbance (in continuous line) and that of the fluorescence area (in dashed form) of the dibenzoyl methanobore difluoride (DBMBF ₂ ), after incorporation in the pores of an MTS by the process according to the invention, as a function of the duration of the sublimation of this compound when this sublimation is carried out at a pressure of 5.33 × 10 ^-3 Pa and a temperature of 25 ° C. FIG. 5 is a graph illustrating the variation of the fluorescence area of DBMBF ₂ , after incorporation into the pores of an MTS by the process according to the invention, as a function of the absorbance of this compound when its sublimation is carried out at a pressure of 5.33 × 10 ^-3 Pa and a temperature of 25 ° C.

FIG. 6 is a graph illustrating the evolution of the fluorescence spectrum of DBMBF ₂ , after incorporation into the pores of an MTS by the process according to the invention, as a function of the duration of the sublimation of this compound when this sublimation is carried out at a pressure of 5.33 × 10 ^-3 Pa and a temperature of 25 ° C.

FIG. 7 is a graph illustrating the evolution of the absorption spectrum of DBMBF ₂ , after incorporation into the pores of an MTS by the process according to the invention, as a function of the duration of the sublimation of this compound when this sublimation is carried out at a pressure of 5.33 × 10 ^-3 Pa and a temperature of 75 ° C. FIG. 8 is a graph illustrating the variation of the absorbance of DBMBF ₂ , after incorporation into the pores of an MTS by the process according to the invention, as a function of the duration of the sublimation of this compound when this sublimation is carried out at a pressure of 5.33 × 10 ^-3 Pa and a temperature of 75 ° C. In Figures 1 to 3, the same references serve to designate the same elements.

Detailed Expression of Embodiments of a Device According to the Invention

Referring first to Figure 1 which shows a device 10 according to the invention in an embodiment specifically designed to incorporate a compound in the pores of a porous material by the method according to the invention, while controlling this incorporation by optical measurements. In addition, this embodiment is designed to perform both vaporization and sublimation, regardless of the chosen temperature and pressure.

As can be seen in FIG. 1, this device comprises two elements, namely a tank 11 and a removable shutter 21 which is designed to be able to be hermetically fixed on the tank 11 by interlocking with a male circular lapping 12 that this latter has in a female ground running 22 that includes the shutter 21.

The vessel 11, in which the porous material is intended to be placed, is of square cross-section and is made of a transparent material, preferably quartz, so that optical measurements can be made as and when the vaporization or sublimation of the compound.

In contrast to the male break-in 12, the tank 11 has a flat bottom 13 in the center of which is fixed a solid cylinder 14 whose face opposite to that located in contact with this bottom is traversed in its diameter by a groove 15 provided with a flexible blade 16, for example metal.

As shown in FIG. 1, the groove 15 is intended to house the end of one or two samples 30 of the porous material to be treated and to ensure, together with the flexible lamella

16, their immobilization in the tank 11.

A sample of porous material that can be treated by means of the device 10 can be either in the form of a block or in the form of a thin layer covering one of the faces of a substrate of the blade type. quartz, glass slide or the like - in which case two samples, identical or different, can be joined by mutual contact of their opposite faces to those covered by the porous material, and maintained as such thanks to the groove 15 and the flexible lamella 16-, again in the form of two thin layers each covering one of the faces of the same substrate.

According to the invention, the cylinder 14 is made of a material adapted to provide thermal insulation or samples of porous material 30 when the tank 11 is cooled or heated. This insulating material is for example Teflon ^® .

The shutter 21 has a dual function: in fact, it serves, on the one hand, to seal the tank 11 when desired and, on the other hand, to connect this tank to a vacuum ramp (not shown in Figure 1) if you want to put it under vacuum. As a result, it is in the form of a straight tube 23, one end of which corresponds to the female ground run-in 22, while the other end 24 is provided with a vacuum valve 25. It laterally bears a bent tube 26 which terminates itself by a male conical grounding 27 adapted to be fitted into a female taper of the vacuum ramp, and whose landing zone on the right tube 23 is located opposite the ducking zone of the duct internal 28 of the vacuum valve 25 on the same tube when the valve is in the open position. Thus, the communication between the tubes 23 and 26 can be alternately opened or closed by rotation of the key 29 of the vacuum valve 25. The use of the device 10 is extremely simple. After having deposited at the bottom of the tank 11, around the base of the cylinder 14, the compound to be vaporized or sublimed, for example by means of a pasteur pipette or a teflon hose, one of the ends of the sample or samples of the porous material to be treated in the groove 15 of the cylinder 14.

The shutter 21 is fixed to the tank 11, the vacuum valve 25 being in the closed position. Either the vaporization or the sublimation of the compound is intended to be carried out without using the vacuum, in which case this vaporization or sublimation is carried out directly by heating the vessel to the temperature chosen to vaporize or sublimate the compound. Either the vaporization or the sublimation of the compound is intended to be carried out under vacuum, in which case the device 10 is connected to the vacuum ramp and the vessel 11 is immersed in liquid nitrogen or in a mixture of dry ice and alcohol. the time required to bring its internal temperature to a value below -40 ° C and thus avoid that, during the evacuation, the compound is brutally sucked and dispersed throughout the volume of the tank 11. It then opens the vacuum valve 25 and the vacuum is allowed to settle in the tank 11. Once the desired vacuum is obtained, the valve is closed and the vaporization or sublimation of the compound is allowed to proceed, possibly in the presence of a source of heat if the temperature chosen to achieve this vaporization or sublimation is greater than the ambient temperature.

As a result of the above, the device 10 shown in FIG. 1 does not make it possible to process more than two samples of one porous material at a time.

Also, FIG. 2 illustrates a device 40 according to the invention in a second embodiment that makes it possible to process six to twelve samples of a porous material in parallel (depending on whether blocks or thin layers are deposited on substrate), while allowing control of this treatment by optical measurements.

To do this, this device 40 comprises six devices 10 as illustrated in FIG. 1, as well as a "cow's udder" connection 50 making it possible to connect these six devices to one and the same vacuum ramp (not shown in Figure 2), for the case where it is desired to establish the vacuum in the tanks 11 of the devices 10. As a result, the connector 50 comprises, at its base, six pipes 51 which each end with a female conical grounding 52 adapted to fit on the male conical grounding 36 of the devices 10 and, at its top, a pipe 53 provided at its end with a male conical grounding 54 fit to fit on a female taper of the vacuum ramp.

Insofar as each device 10 is provided with a shutter making it possible to hermetically close the tank 11 which it comprises - which eliminates any risk of contamination from one device to another - the device 40 offers the possibility of treating simultaneously samples of porous material by different compounds, provided that these treatments can be performed at the same temperature, the pressure may vary from one tank to another.

FIG. 3 shows a device 60 according to the invention in yet another embodiment which is specially designed to allow the simultaneous processing of a large number of samples, for example on an industrial scale, but without control of this treatment by optical measurements.

As can be seen in FIG. 3, the device 60 comprises three elements, namely a cylindrical container 70, a removable cover 80 which is designed to be able to be hermetically fixed on the container 70 by interlocking and a shutter 21, also removable, which is intended to be hermetically fixed on the cover 80 by cooperation of a male circular lapping 81 that has the latter in a female circular lapping 22 that includes the shutter 21.

The latter having the same structure and the same function as the shutter 21 visible in Figure 1, namely ensure a hermetic closure of the container 70 on the one hand, and allow its connection to a vacuum ramp on the other hand, it is only partially shown in FIG.

The container 70 encloses a plurality of tubes 71 arranged in rows and whose bottom is formed by the bottom 72 of this container. These tubes being intended to house the samples 30 of porous material to be treated, their wall 73 is made of a material capable of thermally isolating them from each other such as Teflon. At the center of the bottom of each tube is a solid cylinder 14 having the same structure and function as the cylinder 14 shown in FIG. 1. Thus, the samples 30 of porous material are thermally insulated both by the wall of the tubes. 71 in which they are housed and by the cylinder 14 present in these tubes. This cylinder further allows to channel the gas from vaporization or sublimation in the tubes 71 and to promote its diffusion along the samples of porous material. The device 60 is used according to the same principle as the previous devices. However, since the tubes 71 do not include any individual closure means, they can only be used to treat all of the samples with one and the same compound, otherwise the tubes may be contaminated with each other, unlike the device 40 of FIG.

Detailed presentation of modes of implementation of a method according to the invention

EXAMPLE 1 Incorporation of an Organic Compound into the Pores of an MTS as Monomers

In this example:

the organic compound is a fluorophore, in this case dibenzoylmethanatobore difluoride

(DBMBF ₂ ) which is typically a compound hydrolysing in the presence of traces of water and which is therefore difficult to incorporate in the pores of a porous material in a solvent medium. the MTS is a mesoporous silica of the MCM-41 family; its organized porosity thus consists of hollow spherical pores organized into hexagonal structures. The diameter of these pores is 25 Å. In the present example, it is used in the form of two thin layers, 300 nm (nanometers) thick, each covering one of the faces of a quartz plate measuring 31 cm long and 8 cm wide and 1 mm thick.

the incorporation of DBMBF into the pores of the mesoporous silica is carried out by sublimation

DBMBF ₂ at a temperature of 25 ° C and under pressure of 5,33.10 ^"3 Pa ^{(4.10" 5} torr) by means of a device as illustrated in Figure 1, the vessel 11 is made of quartz, is 42 cm long and 10 cm square, and of which the cylinder 14 located inside this tank is Teflon ^® .

To do this, the quartz plate coated with the two thin layers of mesoporous silica is introduced into the tank 11 of the device 10 and inserted into the groove of the cylinder 14 located inside this tank. About 0.5 mg of DBMBF ₂ is deposited around the base of this cylinder. The shutter 21 is fixed on the tank 11 and the device is connected to a vacuum ramp, the vacuum valve 25 being in the closed position. The vessel 11 is cooled by immersing it in liquid nitrogen for 3 to 4 minutes.

Then, the vacuum valve 25 is slowly opened, after slow pumping and obtaining a vacuum of 5.33 × 10 ^-3 Pa, the valve is closed again, the device 10 is disconnected from the vacuum manifold and the vessel 11 is immersed. in an oil bath heated to 25 ° C, the level of the oil being adjusted to heat the wall of the tank 11 over their entire height in order to prevent the DBMBF ₂ gas condensing on said wall, thus making Optical measurements are difficult and sublimation is allowed to take place for 11 hours.

The incorporation of DBMBF ₂ into the pores of the mesoporous silica is monitored by measuring, at regular intervals (every hour), the absorbance at 350 nm and the fluorescence emitted by this compound at these thin layers. this, by means a Perkin ^® Lambda 900 spectrophotometer and an SPEX Fluorolog 2 spectrofluorometer.

The results of these measurements are illustrated in FIGS. 4 to 6. FIG. 4 represents the variation of the absorbance at 350 nm (in solid line) of DBMBF ₂ and that of the fluorescence area (in dashed form) of DBMBF _2. obtained for an excitation wavelength of 350 nm, as observed during the first 7 hours of sublimation.

FIG. 5 represents the variation of the fluorescence area of DBMBF ₂ as a function of the absorbance at 350 nm of this compound, while FIG. 6 represents the evolution of the fluorescence spectrum of DBMBF ₂ such that observed during the entire duration of the sublimation.

These figures show that:

the absorbance and the fluorescence area of DBMBF ₂ vary linearly as a function of the duration of sublimation for a given temperature (in this case, 25 ° C.) (FIG. 4),

the fluorescence area of the DBMBF ₂ also varies linearly as a function of the absorbance of this compound (FIG. 5), and that the fluorescence spectrum of the DBMBF ₂ remains unchanged throughout the duration of the sublimation.

These results reflect the presence, in the pores of the mesoporous silica thus treated, of a single fluorescent species corresponding to monomers of DBMBF ₂ . Moreover, an absorbance at 350 nm equal to 0.065 is obtained after 7 hours of sublimation of DBMBF ₂ .

By way of comparison, tests carried out by the inventors have shown that when this compound is incorporated in the pores of the same mesoporous silica by dipping samples identical to those used above in a solution of DBMBF ₂ 10 ^-5 M in of cyclohexane free of traces of water, 10 days of soaking are necessary to obtain, after drying in the open air, an absorbance at 350 nm of 0.065.

Example 2: Incorporation of an Organic Compound into the Pores of an STM as Aggregates

This example differs from the previous one only in that the sublimation of DBMBF ₂ is carried out at 70 ° C. in order to increase the rate of incorporation of this compound, and for 15 days.

In this example, the incorporation of DBMBF ₂ into the mesoporous silica thin layers is also monitored by measuring, at different intervals (1:30, 3:00, 18:30, 21:30, 24h, 26h, 42h, 44h, 46h30, 48h30, 50h30, 65h, 67h, 70h, 72h, 74h, 89h45, 91h30, 93h30, 96h30, 98h30, 352h30, 354h30, 356h30, 358h30, 360h30, 362h30), the absorbance of this compound between 300 and 450 nm at these thin layers. The results of these measurements are illustrated in Figures 7 and 8. FIG. 7, which represents the evolution of the absorption spectrum of DBMBF ₂ as a function of the duration of the sublimation of this compound, shows that at the beginning of sublimation, the appearance of this absorption spectrum remains unchanged but that its intensity increases, translating a filling of the pores of the mesoporous silica by the DBMBF ₂ . Then, there is a slight spectral shift that increases over time and corresponds to the formation of aggregates. FIG. 8, which represents the variation of the absorbance at 351 nm of the DBMBF ₂ as a function of the duration of the sublimation of this compound, shows that, for a fixed wavelength (351 nm), this variation follows a first linear regime then bends to reach a plateau value corresponding to a saturation of the pores of the mesoporous silica by the DBMBF ₂ .

Measurement of the full-length absorbance of the thin layers of mesoporous silica indicates homogeneous incorporation of DBMBF ₂ into the pores of these thin layers.

CITES DOCUMENTS

[1] Beck et al., J. Am. Chem. Soc., 1992, 114, 10834 [2] US-A-5,650,311.

[3] US-A-5,824,526

[4] Schulz-Ekloff et al., Microporous and Mesoporous Materials, 2002, 51, 91-138.

10

Claims

A method of incorporating a compound into the pores of a porous material selected from microporous and mesoporous materials obtained by the sol-gel process, characterized in that it comprises the vaporization or sublimation of this compound in a enclosure containing said material.

2. Method according to claim 1, characterized in that the temperature at which the compound is vaporized or sublimated is at least 30 ° C lower and preferably at least 50 ° C at its thermal decomposition temperature.

3. Method according to claim 1 or claim 2, characterized in that the temperature at which the compound is vaporized or sublimated is at most equal to 200 ° C.

4. Method according to any one of the preceding claims, characterized in that the compound is vaporized or sublimed under vacuum, in which case it comprises: a) the evacuation of the enclosure containing the compound and the porous material to obtaining the desired vacuum, and optionally b) heating the chamber to the temperature chosen to vaporize or sublimate the compound.

5. Method according to claim 4, characterized in that the enclosure containing the compound and the porous material is cooled to a temperature of less than or equal to -40 ° C just before being evacuated.

6. Method according to any one of the preceding claims, characterized in that, to vaporize or sublimate the compound at a temperature above room temperature, the enclosure containing the compound and the porous material is heated by immersion in a bath of water. oil maintained at the temperature chosen to vaporize or sublimate the compound.

7. Method according to any one of the preceding claims, characterized in that the porous material is thermally insulated from the wall and the bottom of the enclosure.

8. Method according to any one of the preceding claims, characterized in that it comprises one or more operations for controlling the incorporation of the compound into the pores of the porous material.

9. The method of claim 8, characterized in that the control is achieved by optical measurements.

10. Method according to any one of the preceding claims, characterized in that the porous material present in the chamber is under the form of a block or one or more thin layers covering one and / or the other of the faces of an inert substrate.

11. Process according to any one of the preceding claims, characterized in that the porous material is an inorganic or hybrid organic-inorganic material.

12. Process according to any one of the preceding claims, characterized in that the porous material is a mesoporous material with structuring surfactants (MTS).

13. Device (10, 40, 60) for incorporating a compound into the pores of a porous material chosen from microporous and mesoporous materials obtained by the sol-gel process, characterized in that it comprises: enclosure (11, 70) provided with an opening,

means for immobilizing at least one sample of the porous material in the chamber,

means for thermally isolating this sample from the wall and the bottom of the enclosure,

means for sealing the enclosure, and

- Means for connecting the enclosure to a vacuum generating system.

14. Device according to claim 13, characterized in that the means for immobilizing the sample of porous material also serve as means to thermally isolate it from the wall and the bottom of the enclosure.

15. Device according to claim 14, characterized in that the means for immobilizing the sample of porous material and thermally isolating it from the wall and the bottom of the enclosure comprise a support (14) made of an insulating material, which is secured to the bottom (13) of the enclosure and which is provided with means (15, 16) for holding said sample.

16. Device according to any one of claims 13 to 15, characterized in that the means for sealing the enclosure also serve as means for connecting it to the vacuum generating system.

17. Device according to claim 16, characterized in that the means for sealing the enclosure and connect it to the vacuum producing system comprise a shutter (21) constituted by a first tube (23) which is provided with one of its ends, means (22) for its sealed fixing ^'1' enclosure and at the other end thereof, a vacuum valve (25) and which laterally carries a second tube (26) terminated by means (27) for connecting to the generating system of empty, the mouthing zone of the second tube on the first being such that the communication between these two tubes can be closed or opened by rotation of the vacuum valve.

18. Device according to any one of claims 13 to 17, characterized in that the enclosure (11) is made of a transparent material.

19. Device according to claim 18, characterized in that the enclosure (11) is a four-sided optical tank.

20. Device (40) according to any one of claims 13 to 19, characterized in that it further comprises means (50) for connecting together with at least one device as defined in any one of claims 13-19, to a void producing system.

21. Device (60) according to claim 13, characterized in that the enclosure contains a plurality of tubes (71) adapted to each contain at least one sample of porous material, each tube being provided with means for immobilizing the sample that it contains and means for thermally insulating other tubes, the bottom (72) of the enclosure, and, if appropriate, the wall of this enclosure.

22. Device according to claim 21, characterized in that the means for immobilizing the sample of porous material also serve to thermally isolate the bottom (72) of the enclosure.

23. Device according to claim 22, characterized in that the means for immobilizing the sample of porous material and thermally isolating it from the bottom (72) of the enclosure comprise a support (14) made of an insulating material, which is secured to the bottom (72) of the enclosure and which is provided with means (15, 16) for holding said sample.

24. Device according to any one of claims 20 to 23, characterized in that the means for thermally insulating the sample of porous material from the other tubes (71) and, where appropriate, the wall of the enclosure are constituted by the wall (73) of the tube (71) in which it is located, this wall being formed of an insulating material.

25. Device according to any one of claims 19 to 24, characterized in that the means for sealing the enclosure also serve as means for connecting it to the vacuum producing system.

26. Device according to claim 25, characterized in that the means for sealing the enclosure and for connecting it to the vacuum generating system comprise a cover (80) adapted to be fixed hermetically on the enclosure and a shutter (21) constituted by a first tube (23) which is provided at one of its ends, means (22) for its hermetic fixation on the lid and, at the other end thereof, a vacuum valve (25), and laterally carrying a second tube (26) terminated by means (27) for connection to the vacuum producing system, the zone the second tube is placed on the first tube such that the communication between these two tubes can be opened or closed by rotating the vacuum valve.

27. Use of a process according to any one of claims 1 to 12 or a device according to any one of claims 13 to 26 for incorporating an organic compound in the form of monomers into the pores of a porous material selected from microporous and mesoporous materials obtained by the sol-gel process.

28. Use according to claim 27, characterized in that the porous material is a mesoporous material with structuring surfactants (MTS).

29. Use according to claim 27 or claim 28, characterized in that the porous material is in the form of a block or one or more thin layers covering one and / or the other of the faces of an inert substrate.

30. Use according to any one of claims 27 to 29, characterized in that the compound is a marker or a ligand coupled to a marker.

31. Use according to claim 30, characterized in that the compound is chosen from fluorophores, phosphors and chromophores.

32. Use of a method according to any one of claims 1 to 12 or a device according to any one of claims 13 to 26 for the manufacture of a sensor or multi-sensor chemical.

33. Use according to claim 32, characterized in that the chemical sensor or multi-sensor is intended for the detection or dosing of atmospheric pollutants or gases used in microelectronics.