FR3063660A1 - DEVICE FOR DEPOSITION UNDER ELECTRIC FIELD WITH ELECTRICAL DEFLECTOR - Google Patents

Abstract

The invention proposes a device (10) for deposition in an electric field of a deposition material, of the type comprising a support (14), and a die (16) defining a theoretical deposition axis (A1), an electric field primary being created between the die and the support, - of the type in which the electric deflector comprises at least one pair of electric poles (31a, 31b) on either side of the theoretical deposit axis (A1), each connected at a source of electrical potential (V31a, V31b); characterized in that the electrical poles of the electrical deflector have a mid-height central plane (Pcent), which is arranged, with respect to the support (14), on the other side of a reference plane (Pref) comprising outlet orifice of the die and perpendicular to the theoretical deposit axis (A1), or in this reference plane.

Description

Holder (s): UNIVERSITE CLAUDE BERNARD LYON I Public establishment, NATIONAL CENTER FOR SCIENTIFIC RESEARCH Public establishment.

Extension request (s)

Agent (s): LTL SAS.

ELECTRIC FIELD DEPOSITION DEVICE WITH ELECTRIC DEFLECTOR.

FR 3 063 660 - A1 (5/7 The invention provides a device (10) for depositing a deposit material under an electric field,

of the type comprising a support (14), and a die (16) defining a theoretical axis of deposition (A1), a primary electric field being created between the die and the support,

- of the type in which the electrical deflector comprises at least one pair of electrical poles (31a, 31b) on either side of the theoretical deposition axis (A1), each connected to a source of electrical potential (V31a, V31b );

characterized in that the electric poles of the electric deflector have a central plane (Pcent) of mid-height, which is arranged, with respect to the support (14), on the other side of a reference plane (Ready) comprising l 'outlet opening of the die and perpendicular to the theoretical axis of deposition (A1), or in this reference plane.

The present invention relates to the technical field of the deposition under an electric field of a material for deposition on a substrate, in particular the spinning under an electric field, also called electro-spinning, or the deposition of drops of material of deposition under an electric field, also called "Electro-spraying".

In certain particular cases, it relates more precisely to the technical field of spinning under an electric field a deposition material in the form of discontinuous filaments or, preferably, in the form of a continuous filament, of micron diameter (less than 10 microns), sub-micron (less than 1 micron) or nanometric (less than 100 nanometers).

In the prior art, devices for depositing small diameter filaments have already been proposed, in particular with a diameter less than or equal to one micron. Such devices are for example described in the document "A review on eiectrospinning design and nanofiber assemblies", WE Teo and S. Ramakrishna, Institute of Physics Publishing, Nanotechnology 17 (2006) R89-R106, doi: 10.1088 / 0957-4484 / 17/14 / R01, published in June 2006. Such devices are also briefly mentioned in "Mechanisms, Capabiiities, and Applications of High-Resoiution Eiectrohydrodynamic jet Printing", M. Serdar Onses, Erick Sutanto, Placid M. Ferreira, Andrew G Alleyne, and John A. Rogers, SMALL 2015, Volume 11, N ° 34, September 9 2015, pages 4237-4266, Wiley-VCH Verlag GmbH & Co.

For example, documents US-8,495,969, US-8,906,285,

KR-2010119630, US-2013/0216724 and US-2015/0054201 describe devices for depositing, by electrical field spinning, a deposit material on a substrate. In some of these devices, the die and the support, between which an electrical potential is generated, are movable relative to one another in at least two directions of movement orthogonal to a theoretical axis of deposition which is perpendicular to the plane of support. Spinning is a spinning of a continuous filament and the relative displacement between the die and the support, according to its directions of movement, makes it possible to deposit the deposit of material at the desired location on the substrate carried by the support.

WO-2012/158461 describes various methods and systems for the manufacture of nanoporous membranes. In one embodiment, a system includes pairs of electrodes including substantially parallel electrodes, a power supply controllable to control the electrical potential of each of the pairs of electrodes, and a syringe for ejecting an electrically charged solution a needle to form a nanofiber. The orientation of the nanorab in a layer of nanofibers is determined by the electrical potentials of the pairs of electrodes.

Document WO-2014/079400 describes electrode systems which allow the trajectory of short nanofibers obtained by electro-bending to be bent. Document US-2009/152773 describes, in an electro-spinning device, a pair of electrodes arranged between an outlet orifice of the die ia die and the support on which the fiber is projected. The purpose of this electrode couple, with a device creating a magnetic field, is to stabilize and center the path of the fiber which is created, between the outlet orifice of the die, the die and the support. The device of document WO-2016/075688 describes a portable electro-spinning device in which the outlet orifice is surrounded by a peripheral auxiliary electrode, which determines a single electrical potential all around the axis of projection of the fibers , in order to manage the dispersion or the concentration of short fibers created by the device.

The document High-speed and drop-on-demand prindng with a pulsed eiectrohydrodynamic jet, S Mishra, KL Barton, AG Alleyne, PM Ferreira and JA Rogers, JOURNAL OF MICROMECHANICS AND MICROENGINEERING, 20 (2010) 095026 (8pp), doi: 10.1088 / 0960-1317 / 20/9/095026, describes a technique for depositing drops of deposition material under an electric field, of the “electro-spraying” type. The document Nanoscaie, Electrified Liquid Jets for High-Resoiution Printing of Chargé ', Jang-Ung Park, Sangkyu Lee, Sakulsuk Unarunotai, Yugang Sun, Simon Dunham, Taeseup Song, Placid M.

Ferreira, Andrew G. Alleyene, Ungyu Paik, John A, Rogers, Nano Letters. 2010, 10, 584-591, DOI: 10.1021 / nl903495f, also describes such techniques. The document "Fabrication of high-resolution conductive Unes by combining inkjet printing with soft tithography", Jisu Sung, Byung Ju Kang, Je Hoon Oh, Microelectronic Engineering 110 (2013) 219-223, http://dx.doi.Org/ 10.1016 / j.mee.2013.04.004, describes another example of these technologies.

Such devices can be used to deposit with relatively high deposition rates, measured in terms of the speed of relative movement between the die and the support. However, with such speeds, it appears that certain limits are quickly reached as to the precision of the location of the deposit, or, in particular in the case of a deposit of a continuous filament, that one is not capable of making the deposited filament follow a very tight radius, for example to form a sharp angle between two rectilinear segments of the deposited filament.

In order to respond at least in part to this problem, the invention therefore proposes a device for depositing, under an electric field, a material for deposition on a substrate:

- of the type comprising a support for the substrate and a die having an outlet orifice through which flows the deposition material intended to be deposited on the substrate carried by the support, the outlet orifice of the die defining a theoretical axis depositing the deposit material;

- of the type in which the die and the support are each linked to a source of electrical potential so as to create a primary electric field between the die and the support;

- of the type comprising an electrical deflector which comprises at least a first pair of electrical poles, spaced from one another in a first transverse direction in a plane perpendicular to the theoretical axis of deposition, on either side of the theoretical axis of deposition;

- And of the type in which each electric pole of the pair of electric poles is connected to a source of electric potential, at least one of which can vary its potential; thus, the first pair of poles can create, by a potential difference between the two electric poles of the couple, a first additional electric field oriented in the first transverse direction;

The device is characterized in that the electrical poles of the electrical deflector have a central half-height plane, which is arranged, relative to the support, on the other side of a reference plane comprising the outlet of the die and perpendicular to the theoretical axis of deposition, or in this reference plane.

According to other optional features of the invention, taken alone or in combination:

- The electrical poles of the electrical deflector have a low point, closest to the support, which is arranged, relative to the support, on the other side of a reference plane comprising the outlet outlet of the die and perpendicular to the theoretical axis of deposition, or in this reference plane.

- The electric deflector comprises a second pair of electric poles, spaced from each other in a second transverse direction in a plane perpendicular to the theoretical axis of deposition, not parallel to the first direction, on either side the theoretical deposition axis, each electric pole of the second pair of electric poles being connected to a source of electric potential, at least one of which can vary its potential; thus, the second pole couple can create, by a potential difference between the two electric poles of the couple, a second additional electric field oriented in the second transverse direction.

- To cause a deflection of the trajectory of the deposit material between the outlet orifice and the support, the device is configured to apply a potential difference between the two electric poles of the same pair of electric poles by applying to each of the two poles of the potentials which are symmetrical with respect to a non-zero base potential.

- The theoretical axis of deposition coincides with a geometric axis of the die at its exit orifice.

- The die comprises a needle defining an internal channel for the flow of the deposition material, which has a terminal rectilinear section which ends at the outlet orifice and which has an axis of extension, and the theoretical axis of deposition is confused with the axis of extension of the straight section ended! of the internal channel of the needle of the die, at the level of its outlet orifice.

- The die and the support are movable relative to each other in at least two directions of movement which are not parallel to each other and not parallel to the theoretical axis of deposition.

- The device comprises displacement means allowing relative displacement between the support and the die.

- The device comprises displacement means allowing relative displacement between the support and the die according to in the first transverse direction.

- The device comprises displacement means allowing a relative displacement between the support and the die according to the in the second transverse direction.

- The device comprises displacement means allowing relative displacement between the support and the die in the direction of the theoretical axis of deposition.

- The deposit material is a polymer material.

- The deposit material is extruded in the die in the form of a solution of material in a solvent.

- The deposit material is thermoplastic, and it is spun in the die at a temperature at which it is malleable.

- The device creates a filament of continuous deposit material.

- The device creates a filament of deposit material whose diameter is less than or equal to 1 micron.

- The device creates discontinuous filaments of deposit material.

- The device creates droplets of deposit material.

- The support is a planar support which extends in a transverse plane perpendicular to the theoretical axis of deposition, and, at all points of the theoretical axis of deposition between the die and! E support, the primary electric field is parallel to this theoretical axis.

Various other characteristics will emerge from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments of the subject of the invention.

Figure 1 is a schematic perspective view of an electric field spinning deposition device

Figure 2 is a schematic view of part of an electric field spinning deposition device as illustrated in FIG. 1, provided with an electric deflector according to the invention.

Figure 3 is a schematic side view of the device of FIG. 2, illustrating the relative position of the electric deflector relative to the die.

Figure 4 is a view similar to that of Fig- 3, illustrating the deflection of a continuous filament of material created by the device, with application of an additional electric field by the electric deflector.

Figures 5A to 5D are schematic perspective views illustrating different geometry variants for the electrical poles of an electrical deflector.

Illustrated in FIG. 1 a device 10 for depositing, by electrical field spinning, a material for depositing on a substrate 12 which can be used in the context of the invention. The invention may also be implemented in the case of an electric field deposition device of the “electrospraying” type.

In known manner, the device 10 comprises a support 14 for the substrate 12. The substrate 12 is for example an object on which it is desired to collect the material formed by the device. In the example illustrated, the support 14 is a planar support which extends in two orthogonal directions X and Y. The planar support 14 has a support face 15 which is planar along the extension plane XY of the support 14. Generally , it is expected that this support face 15 is horizontal, therefore perpendicular to the direction of Earth's gravity. However, in certain applications, the support 14 may not be planar, or possibly not be horizontal.

The device 10 also comprises a die 16 having an outlet orifice 18 through which flows the deposition material intended to be deposited on the substrate 12 carried by the support 14. The die 16 comprises a source of deposition material. Depending on the technology used, the deposition material may be in the form of a material in solution in a solvent, or of a material in at least partially molten form.

The deposition material may be or include a polymeric material.

In some of the exemplary embodiments, the polymer is a solid of the polyethylene glycol type, for example a Polyethylene oxide (PEO). This polymer can have a molar mass of 200,000 grams per mole. PEO can for example be dissolved in chloroform (CHCl3) so as to obtain a solution containing 5% by mass of PEO.

Among the other materials which are particularly suitable for deposition, in particular by spinning, under an electric field, alone or as a mixture, mention may be made of the following polymers: polyester, nylon, polysulfone, polyvinyl acetate (PVA), polyacrylonitrile (PAN), poly vinyl pyrrolidone (PVP), chitosan, collagen, cellulose, fibrinogen. These polymers are particularly suitable for deposition in the form of a solution in a solvent. In all cases, the solution containing polymer (s) and solvent can also comprise other molecules or particles.

Alternatively, the deposition material may be or include an inorganic material of the ceramic type.

Alternatively, the deposition material may be or include a thermopiastic material. In this case, the deposition process can be analogous to an extrusion process in which the deposition material is brought into the die in a plastic, malleable state, in particular by raising its temperature above its point of VICAT softening, or above its glass transition temperature or its melting point depending on the nature of the materials concerned. The deposition material can for example be or comprise polyethylene, polypropylene, polystyrene, polyurethane, etc.

The deposition material may for example comprise several materials which are either mixed or not mixed. In the case of unmixed materials, we are dealing with a deposit similar to co-extrusion. In the case of electro-spinning of a multi-material filament, it is possible to have several layers of different materials arranged coaxially along the theoretical axis of deposition. Materials can include fillers, organic or inorganic.

The die 16 generally comprises means for conditioning the material. It may for example include pressurizing means, in particular one or more pumps for a material in liquid solution or for a viscous or plastic material, one or more mechanical drive means for an initially solid material, etc. may include heating means, in particular heating resistance, induction coil, etc.,

The flier 16 generally ends with a needle 20, the end of which forms the outlet orifice 18 through which, in operation, the deposition material flows. The needle can be replaced by a point, the end of which forms the outlet opening of the die. In the case of a needle 20, we are dealing with a tubular body which delimits an internal channel for the flow of the deposition material. The outlet end of this internal channel generally has a straight rectilinear section which ends in the outlet orifice 18. This straight rectilinear section has an axis of extension, generally an axis of symmetry of this straight rectilinear section, which will be hereinafter called the needle axis. The diameter of the internal channel can be from 100 nanometers to 1 millimeter, preferably from 0.2 to 0.5 millimeters.

Most often, the die 16 is oriented so that the needle axis is oriented vertically, in the vertical direction of Earth's gravity. However, in some cases, the orientation may be different.

Most often, in the case of a device 10 comprising a plane support 14, the die is oriented so that its needle axis is oriented perpendicular to the plane of extension XY of the plane support face 15 of this plan support.

Most often, the die 16 is arranged above the support 14, with respect to the direction of attraction of Earth gravity, so that Earth gravity promotes the movement of the material from the outlet 18 from the die 16 to the support 14, more precisely to a substrate 12 carried by the support 14.

It is noted that, in a device according to the invention, the die 16 and the support 14 are positioned one with respect to the other, during the operation of the machine corresponding to the deposition time of the deposition material, so that the outlet orifice 18 of the die 16 is arranged at a distance from a surface of the substrate on which the material is to be deposited, this distance generally being between 1 mm and 10 cm, in particular between 1 cm and 5 cm .

Thus, the outlet orifice 18 of the die defines a theoretical axis of deposition A1 of the deposition material. In the following text, we consider the case where the die 16 has a needle 20 and we consider that the theoretical axis of deposition Al corresponds to the needle axis.

In the case where the die 16 has a needle 20 whose needle axis is oriented perpendicular to the support 14, the theoretical deposition axis A1 is then perpendicular to the support and extends in the direction of the shortest dimension between the outlet 18 and the support 14.

In the case illustrated in FIG. 1, which is the most frequent case, the theoretical deposition axis A1 is coincident with the needle axis and with the vertical direction of gravity, therefore being perpendicular to the extension plane XY of the support 14.

In a device 10 for depositing in an electric field, the die 16 and the support 14 are each linked to a source of electric potential so as to create a primary electric field between the die 16 and the support 14. The die 16 is thus at a potential V16 and the support 14 is at a potential V14,

A source of electrical potential can be a source of positive potential, a source of negative potential, or a source of neutral potential, such as grounding. Either or both sources of electrical potential can or can be a source whose potential is variable over time. For example, as in the example illustrated, the sources of electrical potential linked respectively to the die 16 and to the support 14 are the two terminals of a voltage generator 22. However, one or the other of the potential sources electric can be earth. In all cases, the sources of electric potential make it possible to create between the die 16 and the support 14 a difference in potential generating the primary electric field. In particular, the source of electrical potential linked to the die 16 can be electrically linked to the needle 20, which is generally made of an electrically conductive material or covered with such a material, at least at its internal channel. The difference in electrical potential between the die 16 and the support 14 is generally greater than 500 V, for example greater than 5000 V. It is generally less than 20 000 V.

Under the effect of the electric field, a drop of material formed at the outlet orifice 18 of the die 16, in liquid or at least viscous form, can take (in the form of a cone (called Taylor cone) at the end from which the deposition material is stretched and accelerated towards the support in the form of a continuous filament or discontinuous filaments or droplets. In the case of a needle comprising an internal channel, the final diameter of the filament (s) produced by the die is generally about 1000 times smaller than the internal diameter of the internal channel. Thus, the continuous filament or the discontinuous filaments can have a diameter which belongs to the range going from 20 nanometers to 10 microns, preferably from 50 to 500 nanometers.

In the case of "electrospraying", the viscosity of the deposit material, which is generally suspended in a solvent, is generally lower, so that the deposit material tends, under the effect of the electric field, to form droplets which escape from the die outlet, the same applies to discontinuous filaments in certain electro-spinning processes. In both cases, the value of the primary electric field or the temperature in the die are also factors which can intervene in the form that the deposit material takes between the die and the substrate (continuous filament, discontinuous filaments or droplets).

A device for depositing by "electrospraying" is generally identical to a device for depositing by spinning under an electric field as described above. In an “electrospraying” deposition device, the emitter by which the material flows, the electric field being established between the emitter and the substrate support, is also called by analogy “die”. The droplets can have a diameter ranging from 10 nanometers to 100 micrometers.

It will be noted that, in the case of “electrospraying” or the electro-spinning of discontinuous filaments, the droplets or discontinuous filaments are, during deposition, in “free flight” between the moment of their detachment from the 'outlet of the die and the moment of their impact on the substrate. In the case of electro-spinning of a continuous filament, the filament forms, during deposition, a column of continuous material which is permanently attached on the one hand to the outlet orifice of the die and on the other hand to the substrate.

The speed of extrusion of the deposition material through the die 16 can for example vary from a few tens of microliters to a few milliliters per hour.

The device 10 for depositing in an electric field is configured so that the die 16 and the support 14 are movable relative to one another in at least two directions of movement which are not parallel to each other and not parallel to the theoretical axis of deposit A1. Preferably, it is configured so that the die 16 and the support 14 are movable relative to one another in three orthogonal directions, in other words according to the three dimensions of the space.

Generally, the support 14 and the die 16 are connected to the same chassis (not shown) of the device. With respect to such a chassis, it can be provided that only the support 14 is movable relative to the chassis, the die being fixed relative to the chassis, or that only the die 16 is movable relative to the chassis, the support 14 then being fixed relative to the chassis, or else that the support 14 and the die 16 are both movable relative to the chassis.

The device 10 therefore comprises displacement means 24 allowing relative movement between the support 14 and the die 16. The displacement means can comprise means for guiding the movement, for example one or more elements among slides, joints, articulated arms, etc. The displacement means can comprise motorization means, for example one or more elements from electric motors, pneumatic or hydraulic cylinders, magnetic actuators, etc. The displacement means can include position detection means, in particular sensors, for example position sensors and / or image sensors, etc., making it possible to know, directly or indirectly, the relative position of the die 16 with respect to to the support 14. The displacement means 24 can be arranged directly between the die 16 and the support 14, or they can be independent for the die 16 and the support 14, with for example displacement means between the die 16 and a chassis of the device 10, and / or displacement means between the support 14 and a chassis of the device 10.

According to a proven design, the support 14 can thus be mounted on slides allowing a translation of the support 14 in the X and Y directions orthogonal. In this case, the die 16 is advantageously movable in at least one direction Z perpendicular to the two directions X and Y, for example by being mounted on a slide. In this case, the die 16 can also be mounted on a joint, for example around the X axis or the Y axis, or a spherical joint. As a variant, the die 16 can be installed at the end of an articulated arm comprising several articulations, this arm itself being able to be mounted on one or more slides. In the case of a die 16 installed at the end of an articulated arm, the support 14 can be fixed, in particular fixed relative to a chassis of the device 10.

The device 10 generally includes one or more electronic units 26 responsible for controlling and controlling the various parameters of the machine, in particular for controlling the die, for example the flow rate of deposit material, the temperature, the electrical potentials, and for controlling the relative movement of the die 16 relative to the support 14, including for example in the directions X, Y and / or Z.

The device 10 which is partially illustrated in Figs. 2 to 4 includes all the features described above with reference to the device of FIG. 1 or to the variants mentioned. It also includes an electric deflector 28, an exemplary embodiment of which is described below, in particular with reference to FIGS. 2, 3 and 4.

In general, the electrical deflector 28 comprises at least a first pair of electrical poles, or electrodes, spaced from one another in a first transverse direction in a plane perpendicular to the theoretical axis of deposition, on both sides and d 'other of the theoretical axis of deposition Al.

The electrical deflector 28 may comprise several pairs of electrical poles, in particular 2, 3 or 4 pairs of electrical poles, or more, in which each pair comprises two electrical poles distant from each other in a transverse direction in a perpendicular plane to the theoretical axis of deposition, on either side of the theoretical axis of deposition A1. In the example of Figs. 2 to 4, the electrical deflector 28 comprises four separate electrical poles 31a, 31b, 32a, 32b, or electrodes. Advantageously, these four poles 31a, 31b, 32a, 32b can be arranged in two pairs of electrical poles, the electrical poles of each pair being arranged symmetrically with respect to the theoretical deposit tax A1.

Thus, the example of Figs. 2 to 4 has a first pair of electrical poles 31a, 31b, spaced from each other in a first transverse direction in a plane perpendicular to the theoretical deposition axis A1, on either side of the axis theoretical deposition A1, and a second pair of electrical poles 32a, 32b, spaced from each other in a second transverse direction in a plane perpendicular to the theoretical deposition axis A1, not parallel to the first direction, on either side of the theoretical axis of deposition Al.

In the present text, it is therefore considered that the transverse direction separating the two poles of a pole pair is represented by a straight line perpendicular to the theoretical axis of deposition Al, intersecting the theoretical axis of deposition Al and joining the two poles , and according to which the distance separating the two poles of the couple is minimum.

In this example, the first and second directions are oriented 90 ° from each other, therefore perpendicular. However, other non-parallel orientations are possible.

In the example illustrated, the two electrical poles of the same pair of electrical poles are identical, but arranged in opposite directions on either side of the theoretical deposition axis A1.

Preferably, the two electrical poles of the same pair of electrical poles are equidistant from the theoretical deposition axis A1. In the example illustrated, all the electrical poles of the electrical deflector 28 are equidistant from the axis theoretical deposit Al.

In the example illustrated, the two pairs of electrical poles are identical but angularly offset relative to each other around the theoretical deposition axis A1, in this case 90 °.

The two electrical poles of a pair of electrical poles are preferably arranged at the same height in the direction of the theoretical axis of deposition A1. In the presence of several pairs of electrical poles, the pairs of electrical poles are preferably arranged at the same height along the direction of the theoretical deposition axis A1. However, it is possible, as a variant, to provide a height offset between two pairs of electrical poles according to the direction of the theoretical deposition axis A1. In particular, in the case of two pairs of electric poles, one can have a first couple at a first height in the direction of the theoretical axis of deposition Al and the second couple at a second height according to the direction of the theoretical axis of deposition Al.

Each electrical pole is connected to an additional source of electrical potential V3îa, V31b, V32a, V32b, the value of the potential of which can be varied over time. The potential of each of the sources can thus take at least a first value and a second value. One of the two values can be a zero value, the source then being at the potential of the earth. However, preferably, the potential of each of the additional sources of electrical potential can take, over time, at least a multitude of distinct values comprised between a minimum value and a maximum value. More preferably, the potential of each of the additional sources of electrical potential can vary continuously between a minimum value and a maximum value. The minimum value can be a negative, positive or neutral potential. The maximum value can be a negative, positive or neutral potential. Each source of electrical potential is for example an electrical generator, a converter, etc. Each pole is connected to its additional source of electrical potential by an electrical conductor.

Each electric pole, or electrode, of the electric deflector 28 is made at least in part from electrically conductive material so that, when it is subjected to a non-zero electric potential, it generates an additional electric field in the surrounding space, in particular in the zone of flow of the deposit material being deposited, in particular spinning, between the die 16 and the support 14. In the context of the invention, this additional electric field is superimposed on the field electric primary, and possibly to other additional electric fields created by the other electric poles of the electric deflector 28.

The electric poles can have different geometries and have different sizes. Preferably, the two poles of the same pair of poles have a symmetrical geometry in axial symmetry with respect to the theoretical deposition axis A1. Different possible geometries for an electric pole are illustrated in Figs. SA to SD, without limitation. In these figures, the geometry of the part of the electric pole which is made of electrically conductive material is shown. An electrical pole can be totally or partially covered by one or more insulating materials.

In the example of Figs. 2 to 4, the electrical poles 31a, 31b, 32a, 32b have a geometry as illustrated in FIG. HER. In this example, each electric pole has a size small enough to be considered as punctual with respect to the surrounding electric field. In particular, in this embodiment, each electrical pole of the electrical deflector 28 is included in the acute angle formed by two planes comprising the theoretical deposition axis A1 and forming between them an acute angle TA less than or equal to 20 °.

In the example of FIG. SA, a pole 31a, 31b, 32a, 32b comprises a parallelepiped block, for example of rectangular or square section, having an axis of symmetry R oriented in a radial direction perpendicular to the theoretical axis of deposition Al, and the end of which facing the theoretical axis of deposition Al is extended by a pyramid with a truncated apex, of axis of symmetry R. The electric pole thus has a terminal face 38 which is turned towards the theoretical axis of deposition Al and which extends in a plane perpendicular to the axis of symmetry R, radial. In an exemplary embodiment, this end face 38 has for example a ratio of 2 between its dimension in the direction of the theoretical deposition axis A1, for example 6 millimeters, and its dimension in the perpendicular direction, for example 3 millimeters.

In the example of ia Fig. SB, a pole 31a, 31b, 32a, 32b has a geometry composed of a cylindrical block of revolution having an axis of symmetry R oriented in a radial direction perpendicular to the theoretical axis of deposition and whose end turned towards the theoretical axis of deposition is extended by a convex spherical cap 40 of axis of symmetry R.

However, larger electrical poles, in particular of greater angular extent around the theoretical deposition axis A1 can be envisaged.

In the example of FIG. 5C, a pole 31a, 31b, 32a, 32b has a plane plate geometry 42. The plane plate is for example included in a plane parallel to the axis Al, therefore perpendicular to an axis R oriented in a radial direction perpendicular to l theoretical axis of deposition A1. The flat plate may have, as in the example of FIG. 5C, a rectangular contour, but other contours are possible. The axis R oriented in a radial direction perpendicular to the theoretical deposition axis A1 can be an axis of symmetry for the contour of the planar plate 42.

In the example of FIG. 5D, a pole 31a, 31b, 32a, 32b has a curved geometry around the theoretical axis of deposition Al, that is to say having a radius of curvature in a plane perpendicular to the theoretical axis of deposition Al. In the example of FIG. 5D, the curvature is turned in the direction of the theoretical deposition axis Al. The curvature can be a circular curvature of axis Al. This curved geometry could be a surface geometry, but, in the example illustrated, it can also have the shape of a bar 44 elongated according to a curvilinear curve. This curvilinear curve is for example included in a plane perpendicular to the theoretical axis of deposition A1. In the example of FIG. 5D, an electric pole thus has a bar 44 in an arc of a circle around the theoretical axis of deposition Al, symmetrical with respect to an axis R oriented in a radial direction perpendicular to the theoretical axis of deposition Al.

In the examples of Figs. 5C and 5D, each electrical pole of the electrical deflector is included in the acute angle formed by two planes comprising the theoretical deposition axis A1 and forming between them an acute angle TA comprised for example between 10 and 90 °.

Preferably, in the case of several pairs of electric poles, two adjacent electric poles belonging to two separate pole accounts are separated by a non-zero distance, sufficient to avoid in particular any risk of electric arc.

Preferably, the two poles of the same pair of electric poles of the electric deflector 28 are linked to each other by a frame 34, preferably an electrically insulating frame. In the example illustrated, all the electric poles of the electric deflector 28 are linked to the same frame 34. In certain embodiments, the frame 34 can be mechanically linked to the die 16 by a support 36. This support 36 can be possibly adjustable to allow a relative adjustment of the position of the electric poles of the electric deflector 28 relative to the die 16. This support 36 can be optionally adjustable to allow a relative adjustment of the position of the electric poles of the electric deflector 28 between them.

One can see in particular in FIG. 3 that the electric poles 31a, 31b, 32a, 32b of the electric deflector 28 have a central half-height plane Pcent perpendicular to the theoretical deposition axis A1. The central half-height plane Pcent is the plane which is equidistant from 'a higher Psup plane and a lower Pinf plane. The upper plane Pinf is the plane perpendicular to the theoretical axis of deposition Al which contains a low point of the pole considered, the closest to the support 14 in the direction of the theoretical axis of deposition Al, while the upper plane Psup is the plane perpendicular to the theoretical axis of deposition Al which contains a high point of the pole considered, the furthest from the support 14 in the direction of the theoretical axis of deposition Al.

In the examples illustrated, the central mid-height plane Pcent is a plane in which there is a straight line perpendicular to the theoretical axis of deposition Al, intersecting the theoretical axis of deposition Al and joining the two poles, and according to which the distance separating the two poles of the couple is minimal. However, with other geometries, such a straight line, known as the minimum distance, can be outside the central plane of mid-height.

According to the invention, the central half-height plane Pcent of each pole 31a, 31b, 32a, 32b of the electric deflector 28 is arranged, relative to the support, on the other side of a reference plane Pref comprising the outlet orifice 18 of the die 16 and perpendicular to the theoretical axis of deposition Al, or in this plane. In other words, in the example illustrated, the reference plane Pref is perpendicular to the needle 20. Likewise, in the configuration illustrated, if we consider that the theoretical deposition axis A1 is a vertical axis and that the support 14 is arranged below the die 16, the electrical poles of the electrical deflector 28 have a central plane of mid-height Pcent which is located above the reference plane Pref.

The distance H between the central mid-height plane Pcent of each of the electric poles and the reference plane Pref is for example comprised in the range going from 0 to 100 mm.

Preferably, a line known as the minimum distance between the poles, that is to say perpendicular to the theoretical axis of deposition Al, intersecting the theoretical axis of deposition Al and joining the two poles, and along which the distance separating the two poles of the torque is minimal, is also arranged, with respect to the support, on the other side of the reference plane Pref, or in this plane. In the event that i! there are several of these lines called minimum distance between the poles, it can be provided that each of these lines is arranged, relative to the support, on the other side of the reference plane Pref, or in this plane.

In the example illustrated, the low point of each of the electric poles of the electric deflector 28 is arranged outside the space between the reference plane Pref and the support 14 Thus, the electric poles of the electric deflector have a low point, closest to the support, which is arranged, with respect to the support, on the other side of a Pref reference plane, or in this reference plane. Preferably, each electric pole has an axial extent along the direction of the theoretical deposition axis, namely the distance between the upper plane Psup and the lower plane Pinf, which is for example between 1 millimeter and 10 centimeters.

In the frequent case where the theoretical axis of deposition Al is coincident with the axis of needle and with the vertical direction of gravity, being perpendicular to the plane of extension XY of the support 14 plane, it can be said that the plane mid-height center Pcent of the electric poles of the electric deflector is arranged in the Pref reference plane or above the Pref reference plane.

This particular positioning of the electric poles of the electric deflector 28 makes it possible, surprisingly, to obtain a stable deflection of the filament, filaments or droplets of deposit material between the outlet orifice 18 of the die 16 and the substrate 12 carried by the support 14. This positioning proves to be particularly advantageous in that it prevents the filament or filaments or the droplets of deposit material being deposited, in particular spinning, between the outlet orifice 18 and the substrate 12 , do not clump on one or the other of the electric poles. This positioning makes it possible to act on the deflection of the deposition material as soon as it is emitted at the outlet of the die 16, and thus to optimally control the deposition of material.

Tests have been carried out with a device as illustrated diagrammatically in FIGS. 2 to 4. The following parameters were used:

- shortest distance D between the electric poles and the theoretical axis of deposition Al: 9.5 millimeters

- distance between needle 20 and substrate 14: 30 millimeters.

- axial extent of the poles: 12 millimeters

- distance H between the reference plane Pref and the central plane of mid-height Pcent of the electric poles 31a, 31b, 32a, 32b: H = 6 millimeters (signifying that the low point of the electric poles is in the reference plane Pref).

Under these conditions, we first implemented the device for depositing by spinning under an electric field, without applying a secondary electric field. In other words, each of the electric poles of the electric deflector 28 is then connected to earth, therefore to zero potential. Under these conditions, a stable spinning is obtained for a potential difference between the needle 20 and the support 14 of 13000 volts. For this, we can for example connect the needle to earth, therefore at zero potential, and connect the support to a source of negative potential, at potential -13000 Volts. Thus, the potential difference necessary for electro-spinning is relatively high, in particular due to the presence of the electric poles which, while being connected to a neutral potential, disturb the electric field between the die 16 and the support 14.

In a second step, we realized that it was advantageous to apply to each of the two poles of a pair of electrical poles the same electrical potential Vbase comprised between the potential of the needle of the die 16 and the potential of the support 14, for example a negative potential of 2000 Volts in the example envisaged. Under these conditions, it was found that electro-spinning was possible, under the same conditions of stability as previously, for a potential difference of approximately 6000 volts between the needle 20 and the support 14. This electrical potential Vbase , common to the two electrical poles of the same electrical couple, which promotes the process of electro-spinning is called base potential. It will be noted that, under these conditions, the filament of deposit material which flows between the outlet orifice 18 of the die 16 and the support 14 is not deviated, in any case not significantly.

Thirdly, it has been shown that it is possible to cause a deflection of the path of the filament between the outlet orifice 18 and the support 14 by applying a potential difference "dVd" between the two electric poles of a same couple of electric poles. This deflection is oriented in the transverse direction connecting the two electric poles of the pair of electric poles considered.

In the case where the electric deflector 28 comprises two pairs of electric poles arranged in two non-parallel transverse directions, the electric deflector 28 can thus cause a deflection having non-zero components in the two transverse directions respectively connecting the two electric poles of the two couples of electric poles.

Preferably, this potential difference dVd between the two electric poles of the same pair of electric poles, to obtain the deviation, is obtained by applying, to each of the two poles, potentials which are symmetrical with respect to the base potential. Thus, the arithmetic mean of the electric potentials applied to the two electric poles of the same couple is preferably constant and equal to the basic potential Vbase. Thus, these symmetrical potentials can be written in the following manner Vbase + dVd / 2 and Vbase - dVd / 2. This symmetrical potentiei difference with respect to the base potential makes it possible to limit the impact of the electric field created by the pair of electric poles considered along the direction of the theoretical axis of deposition. This avoids destabilizing the filament of deposit material during deposition, while ensuring effective deflection.

In the particular embodiment described above, it was obtained, as illustrated in FIG. 4, for a deviation potential difference of the order of 3000 Volts applied across a pair of electrical poles, a deviation "df" of more than 4 millimeters, measured in a direction perpendicular to the theoretical axis of deposition A1, between the theoretical deposition axis A1 and the effective point of impact of the deposition material on the substrate 12, for a distance of 30 millimeters between the substrate 12 and the outlet orifice 18.

In the embodiment described above with reference to Figs. 2 to 4, using four poles 31a, 31b, 32a, 32b at 90 ° to one another, the four poles were initially brought to the same base potential Vbase. Once the electro-spinning started, the potentials of the four deflectors were controlled according to the following functions:

V31a (t) = Vbase + A cos (2 x PI x f x t);

V31b (t) = Vbase - A cos (2 x PI x f x t);

V32a (t) = Vbase + A cos (2 x PI x f x t + PI / 2);

V32b (t) = Vbase - A cos (2 x PI x f x t + PI / 2) where A is a potential value, and f is a frequency.

This resulted in a displacement, in Its two directions with phase shift of PI / 2 between the two deflection directions, and a movement of the deposit material wire was obtained, making it possible to obtain a deposit in a circle. Other shapes (sinusoids, straight lines, Lissajous curves, ...) can be obtained by playing on the frequencies, the phases or the functions used to express the potential of each pole.

The device illustrated in the figures thus comprises on the one hand relative displacement means 24 between the die 16 and the support 14, and an electric deflector 28. The relative displacement means generate relative displacement according to at least two directions of displacement not parallel to each other and not parallel to the theoretical axis of deposition. The electric deflector 28 is configured, by the arrangement of the electric poles, so that it creates an additional electric field capable of deflecting the filament or the filaments or the droplets being deposited, in particular in the case of spinning, between the die and the support, in a direction which comprises at least one component parallel to a direction of movement of the relative movement means, preferably two components each of which is parallel to one of the two directions of relative movement.

The invention is not limited to the examples described and shown since various modifications can be made thereto without departing from its scope.

Claims (18)

1 - Device (10) for depositing, under an electric field, a material for deposition on a substrate, - of the type comprising a support (14) for the substrate (12) and a die (16) having an outlet orifice (18) through which flows the deposition material intended to be deposited on the substrate carried by the support, the outlet orifice (18) of the die defining a theoretical axis of deposition (A1) of the deposition material; - of the type in which the die and the support are each linked to a source of electrical potential (22) so as to create a primary electric field between the die and the support, - of the type comprising an electric deflector which comprises at least a first pair of electric poles (31a, 31b, 32a, 32b), spaced from one another in a first transverse direction in a plane perpendicular to the theoretical axis of deposit (Al), on either side of the theoretical axis of deposit (Al), - And of the type in which each electrical pole of the pair of electrical poles is connected to a source of electrical potential (V31a, V31b, V32a, V32b) of which at least one can vary its potential; characterized in that the electrical poles of the electrical deflector have a mid-height central plane (Pcent), which is arranged, with respect to the support (14), on the other side of a reference plane (Pref) comprising l 'outlet opening of the die and perpendicular to the theoretical axis of deposition (Al), or in this reference plane. 2 »Device according to claim 1, characterized in that the electric poles of the electric deflector have a low point, closest to the support (14), which is arranged, relative to the support, on the other side of a plane of reference (Pref) comprising the outlet orifice of the die and perpendicular to the theoretical axis of deposition (Al), or in this reference plane. 3 - Device according to claim 1 or 2, characterized in that the electric deflector comprises a second pair of electric poles (31a, 31b, 32a, 32b), distant from each other in a second transverse direction in a plane perpendicular to the theoretical axis of deposition (A1), not parallel to the first direction, on either side of the theoretical axis of deposition, each electric pole of the second pair of electric poles being connected to a source of electric potential (V31a, V31b, V32a, V32b) of which at least one can vary its potential. 4 - Device according to any one of the preceding claims, characterized in that, to cause a deflection of the trajectory of the deposition material between the outlet orifice (18) and the support (14), the device (10) is configured to apply a potential difference between the two electrical poles of the same pair of electrical poles by applying to each of the two poles potentials which are symmetrical with respect to a non-zero base potential. 5 - Device according to any one of the preceding claims, characterized in that the theoretical axis of deposition (Al) coincides with a geometric axis of the die (16) at its outlet orifice (18). 6 »Device according to any one of the preceding claims, characterized in that the die comprises a needle (20) defining an internal channel for the flow of the deposit material, leque! has a terminal rectilinear section which ends in the outlet orifice (18) and which has an extension axis, and in that the theoretical deposition axis (Al) coincides with the extension axis of the section rectilinear terminal of the internal channel of the needle of the die, at the level of its outlet orifice. 7 - Device according to any one of the preceding claims, characterized in that the die (16) and the support (14) are movable relative to each other in at least two directions of movement which are not parallel to each other and not parallel to the theoretical axis of deposition (Al). 8 - Device according to any one of the preceding claims, characterized in that the device (10) comprises displacement means (24) allowing relative movement between the support (14) and the die (16). 9 - Device according to claims 7 and 8 in combination, characterized in that the device (10) comprises displacement means (24) allowing relative movement between the support (14) and the die (16) according to the first transverse direction. 10 - Device according to claim 9, characterized in that the device comprises displacement means (24) allowing relative movement between the support (14) and the die (16) according to in the second transverse direction. 11 - Device according to any one of the preceding claims, characterized in that the device (10) comprises displacement means (24) allowing relative movement between the support (14) and the die (16) in the direction of the 'theoretical axis of deposition (Al). 12 - Device according to any one of the preceding claims, characterized in that the deposition material is a polymeric material. 13 - Device according to any one of the preceding claims, characterized in that, in the die (16), the deposition material is in the form of a solution of material in a solvent. 14 - Device according to any one of the preceding claims, characterized in that the deposition material is thermoplastic, and in that it is spun in the die (16) at a temperature at which it is malleable. 15 - Device according to any one of the preceding claims, characterized in that it creates a filament of continuous deposition material. 16 - Device according to any one of the preceding claims, characterized in that it creates a filament of deposition material whose! E diameter is less than or equal to 1 micron. 17 - Device according to any one of claims 1 to 15, characterized in that it creates discontinuous filaments of deposition material. 18 - Device according to any one of claims 1 to 15, characterized in that it creates droplets of deposition material. 5 19 - Device according to any one of the preceding claims, characterized in that the support (14) is a planar support which extends in a transverse plane (XY) perpendicular to the theoretical axis of deposition (Al), and in that, at all points on the theoretical deposition axis (Al) between the die (16) and the support (14), the primary electric field is parallel to 10 this theoretical axis.