Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N11/00—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
  • G01N11/02—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by measuring flow of the material
  • G01N11/04—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by measuring flow of the material through a restricted passage, e.g. tube, aperture
  • G01N11/08—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by measuring flow of the material through a restricted passage, e.g. tube, aperture by measuring pressure required to produce a known flow

Definitions

• the present invention relates to a fluidic analysis device, a device for determining characteristics of a fluid, comprising such an analysis device, methods for implementing these devices, and a corresponding screening method.
• the invention aims to treat all types of fluids, namely not only a pure fluid, but also a formulation, namely a fluidic chemical system formed of different components.
• the invention relates more particularly, but not exclusively, to the treatment of a formulation of binary, ternary, or quaternary, or even higher order type, the fractions of the various components are likely to vary.
• the characteristics of a fluid are of several types. By way of nonlimiting reference, mention will in particular be made of physico-chemical characteristics such as viscosity, or else electrical characteristics, such as conductivity. Also suitable optical characteristics, related to the visual appearance of the fluid, in particular as regards the presence "of possible phases, complexes or crystals.
• compositions can include the consequences of interactions and / or arrangements of a component of the formulation with itself or of one or more components with one or more others.
• complex fluids including a vector such as water and other ingredients, the ingredients of which are arranged between them in a defined manner, where appropriate under the action of an external parameter, for example in the form of micelles of more or less complex forms, of lamellar phases, of precipitation phases, of gels physically and / or chemically crosslinked, and whose characteristics are to be evaluated.
• the characteristics can in particular be evaluated for an application purpose to design new formulations.
• the invention aims to remedy more particularly this disadvantage.
• the invention also relates to a device for determining the characteristics of a fluid, according to claim 24 attached.
• the invention also relates to a method of implementing the above analysis device, according to the appended claim 25.
• the invention finally relates to a method for screening a plurality of fluids, according to the appended claim 30.
• FIG. 1 is a front view, schematically illustrating an analysis device belonging to a device for determining characteristics of a fluid, according to the invention
• FIG. 2 is a front view, illustrating means for preparing different formulations, intended to be associated with the analysis device of FIG. 1;
• FIG. 3 is a cross-sectional view illustrating a microchannel formed in a wafer belonging to the analysis device of FIG. 1;
• Figures 4 and 5 are two views of faces, similar to Figure 1 but on a larger scale, illustrating the implementation of the feature determination device according to the invention
• FIG. 6 is a cross-sectional view illustrating an alternative embodiment of the optical analysis means according to the invention.
• FIG. 7 is a front view, similar to FIG. 1, illustrating an alternative embodiment of a device for determining characteristics in accordance with the invention
• FIG. 8 is a perspective view, illustrating more precisely a measurement section of the conductivity, belonging to the device of FIG. 7.
• the determination device firstly comprises an analysis device, more particularly illustrated in Figure 1.
• the analysis device comprises firstly a wafer 2, made from glass, in which are formed different microchannels, according to procedures which will be described in more detail in the following.
• the microchannels engraved in the wafer 2 are represented in thick lines, whereas the tubes connected to these microchannels are represented in finer lines.
• the characteristic section of these microchannels is typically between 100 ⁇ m 2 (for example 10 ⁇ m by 10 ⁇ m) and 1 mm 2 (for example 1 mm by 1 mm). Typically, this dimension causes a substantially laminar flow within these microchannels, with a Reynolds number significantly less than 100.
• Stéphane COLIN microfluidic (EGEM series microsystems treated, published by HERMES SCIENCES PUBLICATION).
• the invention also finds application in millifluidic flow channels, ie whose cross-section is greater than the values mentioned above.
• the cross section of these millifluidic channels can reach a value close to 25 mm 2 , for example 5 mm by 5 mm.
• microchannel flow 4 a first microchannel, called microchannel flow 4, is first dug in the wafer 2.
• a derivative microchannel 6 is stitched on the flow microchannel 4, in the vicinity of the inlet 4 'of the latter.
• the determination device also comprises means for preparing different formulations, shown schematically in FIG. 1, where they are assigned the reference M, and illustrated in greater detail in FIG.
• Preparation M firstly comprise different syringes 8, three in number in FIG. 2, which are associated with syringe pumps 10.
• These syringes and syringe pumps are of a type known per se, so that they do not will not be described in more detail in the following.
• Each syringe 8 is placed in communication with a corresponding tube 12, which opens into a mixing member 14.
• the latter comprises a chamber 16, provided with a plurality of inlets 16 'which are connected to the tubes 12, and an outlet 16' ' , associated with a feed tube 18 extending towards the inlet 4 'of the flow microchannel 4.
• the chamber 16 receives a stirring member 20, of a type known per se, which is for example of magnetic nature.
• the respective outlets 4 '' and 6 '' of the microchannels 4 and 6 are connected to the discharge tubes 22 and 24, which open themselves into an effluent collection container 25.
• These two tubes 22 and 24 are associated with a solenoid valve 26, provided with two inlets 26 'and 26' ', each of which is placed on a respective tube 22 or 24.
• Two pressure sensors 28 'and 28'' are provided in the vicinity of the inlet 4' and the outlet 4 '' respectively of the flow microchannel 4. There are 30 'and 30'' the points, respectively upstream and downstream, in which these sensors are arranged. These are further connected to a processing computer 34.
• the device of the invention is provided with means for analyzing the conductivity. These include two electrodes 36 ⁇ and 36 2 , each of which has a stud 38i, 38 2 extended by a branch 40i, 4O 2 T-shaped.
• Different fingers 42 1 , 42 2 extend from these branches 40 1 , 40 2 alternately. In other words, a finger connected to a branch considered is surrounded by two fingers connected to the other branch.
• the electrodes 36 1 and 36 2 are connected to the computer 34, not shown.
• the constituent material of the electrodes 36i and 362 is for example a gold deposit on a chromium deposit, or a platinum deposit on a tantalum deposit having a thickness of a few tens of nanometers and a width between 10 and 500 microns, or microns.
• the pads 38 1 and 38 2 of these electrodes are connected to an impedance meter 44, of a type known per se, which is itself connected to the processing computer 34.
• the device according to the invention is provided with means of analysis other than the analysis of the viscosity.
• spectroscopic analysis means for example by X-ray fluorescence, X-ray scattering, UV spectroscopy, infrared spectroscopy, Raman spectroscopy.
• the device according to the invention may in particular be provided with thermal analysis means, for example calorimetry type.
• the device according to the invention may in particular be provided with means for analyzing the conductivity.
• the device according to the invention may in particular be provided with optical analysis means. It may especially be a measurement of light scattering, dynamic light scattering, birefringence, or turbidity. It is also possible to perform a thermal analysis, for example of the calorimetry type.
• the optical analysis means comprise a microscope 46, shown schematically, which is provided with two polarizers, of a type known per se. These two polarizers are placed on either side of the horizontal branch 6 2 of the derivative microchannel 6, for the implementation of the device of the invention, as will be seen in more detail in the following.
• Z is noted the observation zone of the microscope 46, which is itself associated with a camera not shown, connected to the processing computer 34 also not shown.
• Figure 3 illustrates a sectional view of the wafer 2, also showing the flow microchannel 4 and one of the electrodes 36i.
• the plate 2 is made of a first glass plate 2 lt against which is inserted the electrode 36i.
• this resin is polymerized by transferring the aforementioned channel pattern. Finally, the spacers not shown are removed, so that the side walls of the microchannel 4 are formed by the portions 3 ⁇ and 3 2 of the polymerized resin.
• the various components are delivered, via the syringes 8, towards the chamber 16 of the mixing member 14. It will be noted that, as usual, the higher the flow rate of a given component is high. the higher its concentration within the final formulation is also high.
• the presence of the stirrer 20 contributes to homogenize the various components so that, downstream of the chamber 16, the tube 18 makes it possible to deliver a well-mixed formulation into the flow microchannel 4.
• This formulation then flows into this microchannel 4, at a flow rate of between 1 .mu.l / h and 10 ml / min, in particular between 10 .mu.l / h and 1 ml / min.
• the inlet 26 'of the flow valve 26 is open, while the inlet 26 '' of the latter is closed, so that the fluid flows only in the microchannel 4 but not in the 6. It is then carried out simultaneous measurements of viscosity and conductivity.
• the two sensors 28 'and 28' ' are used which, in a manner known per se, deliver a voltage which is a function of the pressure exerted on a piezoresistive material.
• the computer 34 to which this measurement is transmitted, then converts this voltage into a differential pressure, also known per se.
• the sensors send electrical voltages to the computer, which multiplies them by a given factor, specific to these sensors, which allows access to the pressure of each sensor. Finally, a pressure is subtracted at the other pressure, which gives the pressure difference between the two sensors.
• the computer determines the viscosity of the fluid flowing in the microchannel 4. This calculation of the viscosity involves various parameters which are either fixed a priori or determined in real time. This viscosity depends in particular on the nature of the section of the microchannel 4.
• the viscosity ⁇ is equal to: where H is equal to the height of the microchannel section, w is the width of the microchannel, ⁇ P is the differential pressure determined by the computer 34, as seen above, Q is equal to the flow rate of the fluid in the microchannel 4, and 1_ is equal to the distance between the upstream 30 'and downstream 30' points.
• ⁇ ⁇ P * ⁇ * R 4 / 8Ql ⁇ , where R is the radius of the microchannel, ⁇ P, Q and 1 being defined above.
• the conductivity measurement is obtained thanks to the electrodes 36 1 and 36 2 associated with the processing computer 34.
• the electrodes are connected to an impedance meter which measures the impedance of the fluid in Siemens while considering a circuit in parallel.
• the response of the electrodes is also calibrated, conventionally, to access the actual conductivity.
• the impedance meter measures the resistance R of the fluid, then the computer performs the inverse 1 / R calculation, namely the conductivity value.
• the state of the inlets 26 'and 26' 'of the solenoid valve 26 is first changed. Under these conditions, the inlet 26' is now closed, while the input 26 '' is now open, as shown in Figure 4. This then allows to fill the microchannel derivative 6 with the fluid sample to study, while stopping the flow in the microchannel 4. This fluid is now present at the right of the observation zone Z.
• the fluid is substantially immobile, which guarantees a high accuracy in the optical measurement which is then performed.
• the displacements of the fluid during the various operations, described above, are materialized by the arrows fi and f 2 . It should be emphasized that the fact of filling the derived channel, independently, makes it possible to use a reduced quantity of the fluid to be treated.
• the camera coupled to the microscope then ensures, in a manner known per se, the shooting of the fluid sample through the observation zone Z.
• the two polarizers used in this implementation, allow a visual differentiation of the phases. It is recalled that a polarizer filters the light and therefore leaves only one component of it, in a well-defined sense.
• any light is prevented from passing when the fluid has a homogeneous structure.
• the fluid has a non-homogeneous structure, in particular of lamellar and / or spherulitic type, it is possible to observe light variations in microscopy.
• FIG. 6 illustrates an alternative embodiment of the invention, more particularly concerning optical analysis means.
• This figure 6 shows the wafer 2 partially represented, as well as a section of the horizontal branch 6 2 of the derivative microchannel 6.
• a support 55 capable of being secured to the wafer 2 by any suitable means, in particular by interlocking.
• This support 55 U-shaped, has two wings 55i and 55 2 which cap the edge of the wafer 2.
• One 55 ⁇ of these wings supports a light source 56 ⁇ , for example of the LED type (Light Emitting Diode) or laser, while the other wing 55 2 supports a light intensity detector 56 2 , for example of the photodiode type.
• the source 56i and the detector 56 2 are placed facing each other, on either side of the branch ⁇ 2 .
• two crossed polarizers 58 1 and 58 2 are interposed between the wafer and each wing 55 1 and 55 2 of the support 55. These polarizers are for example secured to the support, by any appropriate means.
• the detector 56 2 is connected to a computer not shown, allowing the recovery of the signal from this detector, as well as its computer processing.
• FIG. 6 provides access, in a manner known per se, to birefringence values of the fluid flowing in the microchannel 6. variant not shown, we can not appeal to the polarizers 58i and 58 2 . Under these conditions, it is then possible to access turbidity values of this fluid.
• the embodiment of Figure 6 has specific advantages. Thus, it firstly has a simple mechanical structure, since the support 55 provided with the optical means 56 1 and 56 2 can be attached to the wafer, in particular removably. In addition, the use of a light source associated with a light intensity detector makes it possible to obtain a continuous signal.
• FIG. 7 illustrates an alternative embodiment of the invention.
• the feed tube 18 opens into a tubular flow member 102, the internal volume of which forms a flow channel 104 whose dimensions are similar to those of the channel 4 formed in the wafer 2.
• such a tubular flow member is an elongate flow member of closed section, the transverse profile may have any type of shape, in particular oval or square.
• such a member is not formed in a solid body. The flow channel of the fluid to be analyzed is therefore formed by the internal volume of the tubular flow member.
• This tubular flow member 102 has different sections, allowing different types of analysis. We thus find a first section 102i which opens into a connector 105i connected to a second portion 102 2, for measuring the conductivity, which is more specifically illustrated in Figure 8.
• This stretch is' formed of two concentric electrodes, the internal electrode 136i is a needle made for example of steel stainless. Furthermore, the outer electrode 1362, which forms the outer wall of the section 102 2 / is also made of stainless steel. These two electrodes 136i and 136 2 are held relative to one another through the connector 105i and a junction 105 2 T-shaped.
• the electrodes 136 1 and 136 2 are connected to a processing computer, not shown. In the same way as explained with reference to the first embodiment, the fluid flow in the vicinity of these two electrodes makes it possible to determine a conductivity value.
• the open end of the junction 105 2 is connected to a pressure sensor 128, similar to those 28 'and 28''of the first embodiment.
• the second embodiment differs from that described with reference to FIG. 1, in that a single pressure sensor is provided insofar as the atmospheric pressure is also taken advantage of.
• the tubular flow member 102 comprises a third section, in the form of a tube 102 3 made of an X-ray permeable plastic material.
• This tube is thus, for example , made in KAPTON.
• This section 102 3 is associated with an optical analyzer 146, using an X-ray beam 146i. This makes it possible to take a shot of the fluid sample through the tube 102 3 .
• the invention relates to a fluidic analysis device comprising at least one flow channel, formed in a wafer and / or formed by the internal volume of a tubular member, means for supplying this fluid in this channel, as well as a means for analyzing the viscosity of the fluid.
• a first portion of the flow channel is formed in a wafer, as in Figure 1, while another part of this channel is formed by the internal volume of a tube, as in FIGS. and 8.
• the viscosity and conductivity analyzes within the wafer and the optical analysis within the tube can be performed.
• heating means are associated with the wafer or tube, and / or the mixing means.
• the presence of different phases can be identified from the analysis of the conductivity.
• the conductivity value By observing a possible instability of the conductivity value, it is possible to conclude that there are different phases, in particular plugs, such as drops or bubbles.
• the invention makes it possible to carry out a viscosity analysis, so as to access in particular the viscosity as a function of the composition of a formulation, and / or as a function of shear applied to the formulation, and / or as a function of temperature and / or as a function of aging.
• the invention also makes it possible to carry out another analysis, for example a spectrometric, optical, calorimetric and / or conductimetric analysis.
• the various operations, described above, can be controlled by computer means, computer type. Under these conditions, using this computer, the various formulations are programmed, as well as the control of the syringe shoots in order to automatically ensure this formulation sequence.
• the invention achieves the previously mentioned objectives.
• the various analysis means which is equipped with the device of the invention, can quickly obtain several measurements of a fluid sample (a formulation) having the same composition. Moreover, the composition of the fluid to be studied can be modified simply and quickly.
• the invention can therefore be implemented in the context of the design of new products intended to be used as an ingredient in formulations.
• the invention can also be implemented in the context of the design of new formulations comprising new ingredient combinations (or combinations in new quantities).
• the screening method that can be implemented in accordance with the invention is clearly more advantageous than those of the state of the art, insofar as it is accompanied by a speed of execution considerably. improved. In this respect, it can be considered that such a screening method can be implemented between 2 and 10 times faster than in the prior art.
• the invention may, according to another application, be implemented in the context of an industrial production control.
• the device is particularly useful for identifying and / or designing compounds and / or formulations useful in the following fields: coating formulations, for example paints fluid formulations for the extraction of oil and / or gas
• cosmetic formulations in particular comprising structured phases, in particular structural structured surfactant liquids (“SSL”), detergent formulations for household care, in particular comprising structured phases,
• SSL structural structured surfactant liquids
• the invention is particularly advantageous for the study of surfactants, polymers and / or formulations, often aqueous formulations, comprising one or more surfactant (s), and / or one or more polymer (s) and, where appropriate, other additives such as salts.
• the invention can very advantageously be used to study and / or design structured formulations comprising a combination of several surfactants, optionally at least one polymer and optionally salts.
• aqueous structured surfactant systems optionally comprising salts, having an effective structuring ratio (for example with at least 40% by volume of structured phases, preferably at least 75%, more preferably at least 95%), with appropriate rheology, a suitable suspending power (rheological threshold).
• the structuring is due to the formation of spherulitic and / or lamellar phase arrangements (observable by optical means) which modify the rheology, conductivity (by incorporating into the structure more or less salts and / or water and / or by changing the mobility of these species).
• the invention makes it possible to easily and quickly identify such systems or to obtain information that may suggest formulation modifications to be made in order to obtain such systems.
• Various ternary formulations are made from a silicone oil of 20OcP viscosity, water and a surfactant. These various formulations are dispensed into a wafer, whose flow channel has a cross section of 1 mm by 1 mm and a length of 43 mm, between two pressure sensors. Furthermore, cross-polarization and conductivity microscopy measurements are made in this wafer.
• the flow channel of this wafer is connected to a 1.2 mm long KAPTON tube and 10 cm long for X-ray measurement. All these measurements are carried out in flowing the different formulations at a rate of 2000 // 1 / h.
• a micromixer is placed upstream from PMMA and a structured stainless steel plate for possible heating.
• a VITON seal seals both parts of the mixer.
• a magnetic bar 8 mm in length and 1 mm in diameter is used, rotating at a speed of rotation of 50 revolutions per minute.
• Table 1 shows the conductivity values in ⁇ S (Siemens micro), placed in a ternary diagram. Moreover, Table 2 shows the viscosity values in cP, within this same diagram.
• different shots are taken with the cross-polarization microscope associated with the wafer. An X-ray diffraction measurement is also carried out in the KAPTON tube. The results are consistent with those expected from traditional measurements.

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