Multifunctional product in the form of electrically conductive and/or electrically and/or magnetically polarizable and/or thermally conductive paste or ink or glue, method for the production thereof and use of said product

Abstract

A method of formulating and using pastes, inks or adhesives made of electrically conductive and magnetically polarizable materials bound by a polymeric matrix includes depositing a paste, ink or adhesive at a low temperature, and using the paste, ink or adhesive as an electrically and magnetically and thermally active component, either in a wet or dried state. The polymer matrix provides the deposited product with mechanical properties, which integrate with the electrical and magnetic functions expressed by the other materials in the product. The product can be deposited both on a flexible and a rigid substrate, and can be used directly on the substrate, or in a form released from the substrate. The deposited product may be used as an electromagnetic and thermal component and device, such as an electromagnetic welder, electromagnetic heater, multifunctional material and coating passivating a static electric charge, magnetoresistive sensor, electromechanical relay, or electromechanical actuator.

Claims

1. A functional product provided as an electrically, magnetically, and/or thermally active paste, ink, or glue, consisting of: a first component consisting of an electrically conductive component, and/or an electrically and/or magnetically polarizable component; and a matrix of a polymeric material binding the first component, the matrix being electrically conductive, and/or magnetically and/or electrically polarizable, or electrically non-conductive and/or magnetically non-polarizable.

2. The functional product according to claim 1, wherein the electrically conductive component is constituted by one of the following materials or a combination thereof: a magnetically non-polarizable material comprising carbon, a metal material, and a non-ferromagnetic or ferromagnetic material.

3. The functional product according to claim 1, wherein the magnetic component and is constituted by one material or a combination of materials that are electrically conductive ferromagnetic materials, or magnetically polarizable and electrically insulating materials.

4. The functional product according to claim 1, wherein the electrically polarizable component is constituted by an electrically non-conductive but electrically active material.

5. The functional product according to claim 1, wherein the functional product is provided as a glue when a solvent is not added to the one or both of the first component and the matrix.

6. The functional product according to claim 1, wherein the matrix is constituted by one or a combination of two or more of polyurethane; polydimethylsiloxane; co-polyesters of polyethylene terephthalate; and polyvinylacetate.

7. A method of producing a functional product according to claim 1, the method comprising the steps of: (i) selecting one or more polymeric materials for the matrix; (ii) dissolving the matrix; (iii) selecting a material or a mixture of materials selected from the group consisting of: electrically conductive materials, electrically polarizable materials, and magnetically polarizable materials that are electrically conductive or electrically insulating materials; for the electrically insulating and magnetically non-polarizable materials, using non-polymeric components having both electric and magnetic properties; for the electrically insulating and magnetically polarizable polymeric components, using non-polymeric components having electric properties; and for the electrically insulating and magnetically non-polarizable polymeric components, using non-polymeric components having magnetic properties; (iv) homogeneously mixing the matrix and the material or the mixture of materials by mechanical stirring to produce the functional product; and (v) depositing the functional product on a substrate, by and transforming the deposited functional product in a functional object having a liquid or solid phase with a desired geometrical shape; wherein step (ii) is carried out alternatively or in combination according to a process selected from the group consisting of: a thermal heating process, using a solvent to dissolve polymeric materials of the matrix; a thermal heating treatment and solvent combination; and a first initial step comprising thermally melting the matrix, a subsequent second step of adding the solvent, and a heating/cooling step at a temperature equal or lower than 100° C.

8. The method according to claim 7, wherein the functional product is produced as a paste or an ink by carrying out step (ii) by using the solvent to dissolve the matrix.

9. The method according to claim 7, wherein said solvent is an organic solvents or water.

10. The method according to claim 7, wherein the matrix is dissolved in a volatile organic solvent having a high vapor pressure.

11. The method according to claim 7, wherein the solvent is an organic solvent selected from the group consisting of chlorobenzene, o-dichlorobenzene, m-xylene, o-xylene, p-xylene, dimethylsulfoxide, and 1-methoxy-2-propanol.

12. The method according to claim 11, wherein the solvent has a vapor pressure at 25° C. of: about 12 mmHg for chlorobenzene; about 1.4 mmHg for o-dichlorobenzene; about 8.3 mmHg for m-xylene; about 6.6 mmHg for o-xylene; about 8.7 mmHg for p-xylene; about 0.6 mmHg for dimethylsulfoxide; or about 10.9 mmHg for 1-methoxy-2-propanol.

13. The method according to claim 7, wherein step (iv) is performed by mechanical stirring at a temperature between about 60 and 90° C.

14. The method according to claim 7, wherein the functional product provided as a glue by carrying out step (ii) using a thermal treatment that comprises heating the matrix without using any solvents.

15. The method according to claim 7, wherein step (iv) comprises mixing by mechanical stirring at a temperature between about 200° C. and 250° C.

16. The method according to claim 7, further comprising a drying step carried out at a drying temperature lower than 100° C.

17. The method according to claim 7, further comprising the step of manufacturing electronic components and devices by disposing the functional product on a flexible substrate.

18. The method according to claim 17, wherein said electronic components and devices are: electrical connectors and/or electrical wiring; electric welders; materials and coatings for heat exchangers; electric heaters; anti-electrostatic materials and coatings; flame retardants; magnetoresistive sensors; electromechanical relays/reed relays; circuit breakers; or electromechanical actuators.

Description

[0062] These and other features and advantages of the present invention will become clearer from the following description of some embodiments illustrated in the attached drawings in which:

[0063] FIG. 1 schematically shows an embodiment of the invention consisting of a magnetoelectric welding device for plastics.

[0064] FIG. 2 shows a schematic illustration of a magneto-resistive sensor made with functional materials according to the present invention.

[0065] FIG. 3 shows graphs related to:

[0066] a) magneto-resistive response of a magneto-resistive sensor made with the products of the present invention according to the density of the magnetic flux;

[0067] b) magneto-resistive response of the magneto-resistive sensor as a function of time, while on/off cycles of magnetic flux density are applied at different frequencies between 0.5 Hz and 10 Hz.

[0068] FIG. 4 shows a graph relating to the comparison of the magneto-resistive response over time of magneto-resistive sensors, made with the products of the present invention, in the dry and wet state.

[0069] FIG. 5 schematically shows an embodiment of an electromagnetic relay made with the products of the present invention.

[0070] FIG. 6 schematically shows an embodiment of a reed relay made with the products of the present invention.

[0071] FIG. 7 schematically shows an embodiment of an electromechanical actuator, i.e. a valve.

EXAMPLE 1

[0072] Example 1 refers to electrical and magnetic products, particularly to a precise formulation of electrically conductive and magnetically polarizable products, for example in the form of pastes or inks or glues.

[0073] In this example, a graphene flake powder is used for the formulation of the electrically conductive component of the product.

[0074] The graphene flake powder is produced from graphite through a freeze-drying process of a dispersion of graphene flakes in N-methyl-2-Pyrrolidone, the latter obtained by “wet-jet milling” exfoliation from graphite. Further details on said graphene production process by means of wet-jet milling are contained in Fondazione IIT patent IT102015000077259, Del Rio Castillo et al.

[0075] A magnetic component of Fe or Fe3O4 is provided. The Fe component is in the form of commercially available Fe powder (MAGNET EXPERT, UK) and is used as a magnetically polarizable and electrically conductive component.

[0076] The Fe.sub.3O.sub.4 component is in the form of commercially available Fe.sub.3O.sub.4 nanoparticle powder (Sigma Aldrich) and can be used as a magnetically polarizable and electrically insulating component.

[0077] PET is used as a polymeric material for the polymer component of the product. Experimentally, commercially available PET called Vivak, produced by Bayer Sheet Europe GmbH, Germany, was used.

[0078] The percentage by weight of the polymeric component in the solid component of the electric paste (called P1) is 20, as summarized in detail in the following table:

TABLE-US-00003 Component weight content Pastes Component family (wt %) P1 Polymer (PET) 20 Graphene flakes Up to 80 Other components To fill up to 100 P1a Polymer (PET) 20 Graphene flakes 50 Fe powder 30 P1b Polymer (PET) 20 Graphene flakes 50 Fe.sub.3O.sub.4 30 nanoparticles

[0079] PET is melted at 200° C. for 30 minutes and dissolved in chlorobenzene at a concentration of 50 g/l. The mixture thus obtained is mechanically stirred for 1 hour at 90° C. Subsequently, the graphene flake powder with a percentage by weight in the solid component of 50% and the Fe powder in an amount of 30% by weight for the product P1a (excluding the solvent) and the powder are added to the PET mixture of Fe.sub.3O.sub.4 nanoparticles, in an amount equal to 30% by weight for the product P1b (excluding the solvent). The paste is further mechanically stirred at 50° C. for 12 hours.

[0080] By depositing the aforementioned paste on flexible substrates, for example, plastic and/or paper and/or fabrics or on rigid substrates, such as for example glass and/or metal sheets and its subsequent drying at room temperature, electrically conductive components are obtained in the form of a coating such as film or the like.

[0081] The thickness of the resulting components can vary between 30 μm and 100 μm, depending on the parameters of the deposition process.

[0082] In particular, the films on PET substrates were used directly in the form in which they were produced, while the films on glass substrates were separated from the substrate by delamination with the aim of obtaining films of electrically conductive material separated from the substrate (self-standing film).

EXAMPLE 2

[0083] Different pastes/glues/inks with electrical and magnetic properties are formulated in the type of electrically conductive and magnetically polarizable paste/glue/ink (P2) or electrically insulating and magnetically polarizable paste/glue/ink (P3) such as those known in the state of the art. As described in the following examples, these pastes/glues/inks can be used for the production of polarizable magnetic products.

[0084] In the case of the electrically conductive and magnetically polarizable product (P2), Fe powder, commercially available (MAGNET EXPERT, UK), is used as a material for the electrically conductive and magnetically polarizable component. Poly (vinyl alcohol) (PVA), commercially available (Sigma Aldrich), or commercially available polydimethylsiloxane (PDMS) and named SYLGARD 184 (DOW CORNING) are used as polymeric materials for the polymer component.

[0085] With reference to the above, water and/or ethanol are used in an embodiment such as solvents for the PVA for the formulation of products in the form of paste or ink.

[0086] In an embodiment, chlorobenzene, chloroform, acetone can be used as solvents for the PDMS for the formulation of products in the form of paste or ink or glue.

[0087] In the case of the electrically insulating and magnetically polarizable product (P3), the commercially available Fe.sub.3O.sub.4 nanoparticle powder (Sigma Aldrich) is used as the electrically polarizable and electrically insulating component.

[0088] The electrically insulating and magnetically and/or electrically polarizable products can be transformed into electrically conductive and magnetically polarizable products (P4, P5) by adding powdered graphene flakes, preferably obtained by drying the dispersion of graphene flakes in N-methyl-2-pyrrolidone obtained by wet-jet milling exfoliation of graphite described in IIT patent IT102015000077259, Del Rio Castillo et al. or by adding Fe powder.

[0089] The different components of the products (such as pastes/inks/glues) are mixed with a planetary centrifugal mixer (Thinky ARE-250, Mixing and Degassing Machine, UK) for 3 minutes at 2000 rpm.

[0090] The percentages by weight, referred to the sum of the weights of the solid components excluding the solvent, of the various components of the products indicated as P2, P3, P4 and P5 are indicated in the following table.

TABLE-US-00004 Product Component family wt % P2 Polymer (PVA or 25 PDMS) Fe powder 75 P3 Polymer (PVA or 25 Reference product known PDMS) in the art Fe.sub.3O.sub.4 nanoparticle 75 powder P4 Polymer (PVA or 25 PDMS) Fe.sub.3O.sub.4 nanoparticle 62.5 powder Graphene flakes 12.5 powder P5 Polymer (PVA or 25 PDMS) Fe.sub.3O.sub.4 nanoparticle 62.5 powder Fe powder 12.5

[0091] By depositing electrical and magnetic products on flexible substrates such as plastic and/or paper and/or fabrics or on rigid substrates such as glass and/or metal sheets, the electrically conductive and magnetically polarizable components are obtained in the form of a film both in the wet state (composition based on PVA), both in dry state (composition based on PDMS).

[0092] An embodiment of the invention provides that wet film can be encapsulated by a thin plastic film (400 μm) to avoid drying.

[0093] The solid state films are dried at 60° C. for 60 minutes.

[0094] The thickness of the resulting components can vary between 35 μm and 100 μm, depending on the parameters of the deposition process.

[0095] The films on PET substrates are used directly in the form in which they were produced, while the films on glass substrates are separated from the substrate by delamination with the aim of obtaining films of electrically conductive material separated from the substrate (self-standing film).

[0096] The latter can be easily attached to plastic, glass, or metal substrates due to the adhesiveness of the PDMS.

[0097] Some electronic devices made using the products or their corresponding embodiments in films will be described below according to examples 1 or 2.

EXAMPLE 3 ELECTROMAGNETIC WELDING

[0098] The material defined P1 in example 1 is used to manufacture an electric welder for welding plastics and/or elastomers and for repairing electrical connections on plastic substrates and/or elastomers, as shown in FIG. 1.

[0099] Electric welding through the use of P1 is performed through the following steps: [0100] i) P1 is deposited by a doctor blade in the form of a strip or track indicated with 100 in FIG. 1 in one of the two embodiments described in example 1, or on PET or glass. In the latter case, the film is subsequently delaminated from the substrate; [0101] ii) the embodiment of P1 contacts the broken component indicated with 110 in FIG. 1; [0102] iii) a potential difference is applied to the opposite ends of the track 100 so that it conducts an electric current. The heat generated by the Joule effect melts track 100 which fills interstices 130 of the breaking zone and joins the broken component.

[0103] With reference to step iii) it is possible to foresee a continuous or alternating potential difference. In an embodiment, an alternating potential difference can be applied to the ends of track 100 by generating a continuous change in the magnetic polarization of the magnetic components. The resistance to rapid change of magnetic fields produces additional heat which adds up to heating by Joule effect.

[0104] According to an executive variant of step iii) instead of a potential difference it is possible to apply an externally generated alternating magnetic field (for example from a coil in which an alternating current flows). This alternating magnetic field can be used to heat track 100 through the electromagnetic induction process.

[0105] FIG. 2 shows the dependence of the electrical resistance as a function of the current applied for

[0106] a) a PET track coated with a P1 film and

[0107] b) a track of a P1 film separated from the substrate by delamination.

[0108] The example refers to a track with a geometric area of 1×5 cm2, thickness of about 75 μm.

[0109] For the specific case of the products P1a and P1b of example 1, by applying an electric current greater than 300 mA, both tracks melt well to perform the sealing function of plastics and/or elastomers.

EXAMPLE 4 ELECTROMAGNETIC HEATERS

[0110] In this example, the tracks made using the defined product P1, such as those shown in example 2, are used as electric heaters. These heaters work by applying a voltage to the ends of the tracks themselves. The heat is generated by Joule effect and the temperature can be easily controlled up to values compatible with the thermal stability of the substrates, i.e. temperatures below the softening and/or melting and/or flammability temperature of the substrate.

[0111] According to an embodiment, an alternating potential difference can be applied alternately to a constant electrical voltage at the ends of the tracks, generating a continuous change in the magnetic polarization of the magnetic components. The resistance to rapid change of magnetic fields produces additional heat which adds up to heating by Joule effect.

[0112] According to an executive variant, alternatively to a potential difference, an alternating magnetic field generated externally (for example from a coil in which an alternating current flows), can be used to heat the tracks through the electromagnetic induction process.

EXAMPLE 5

[0113] Multi-functional (magnetic) anti-electrostatic materials and coatings, namely multi-functional (magnetic) materials and coatings passivating the static electric charge (anti-triboelectric);

[0114] The product P1 of example 1 can also be used to obtain an anti-electrostatic effect or an anti-triboelectric plastic coating.

[0115] An embodiment provides a film comprising material P1 of Example 1 with a thickness of 40 μm and equipped with a surface electrical resistivity (Rsheet) of 21±0.5 Ω/sq.

[0116] A PET coated with a film of material P1 according to example 1 75 μm thick has an R.sub.sheet of 39±2.2 0/sq. These R.sub.sheet values enables the dissipation of the static electric charge, avoiding unwanted triboelectric effects, including: electrostatic discharges in electronic devices made with plastic materials; the attraction and adhesion of dust particles on the surfaces of plastic materials, which cause the formation of dirt residues in electrically charged fabrics during the stages of their processing. As for the reduction of the attraction/adhesion effect of the dust particles, this type of coating has a self-cleaning function.

[0117] A PET with coating of a film of material P1 according to example 1 also has a shielding effect against electromagnetic waves and this effect enables a reduction of between 5 and 10 dB in the frequency range of electromagnetic waves of between 5 MHz and 10 MHz, as shown in FIG. 3. This frequency field of electromagnetic waves includes the NFC (Near Field Communication, or 13.56 MHz) frequency. PET coated with the aforementioned material P1 therefore acts as a protection for a body against NFC electromagnetic waves.

EXAMPLE 6 MULTIFUNCTIONAL (MAGNETIC) ELECTRODES FOR ENERGY GENERATORS AND CONVERTERS

[0118] Products P1, P2, P4 and P5 with PDMS as a polymer component can be used as electrodes for magnetically assisted triboelectric generators. P2, P4 and P5 films on rigid or flexible substrates, or films of the above products in “self-standing” form, can be used as negative electrodes of triboelectric generators, both rigid and flexible. In particular, PDMS is intrinsically a negative triboelectric material. The presence of graphene makes the aforementioned films electrically conductive, capable of performing the function of electrodes to make the charge separate at the interface between positive and negative triboelectric materials flow in an external circuit. In addition, the magnetic component allows to assist the operation of the triboelectric generator, guaranteeing a control of the mechanical movement through the application of a magnetic field. In the latter configuration, the devices are called “magnetic-assisted non-contact triboelectric generator”. Examples of such devices according to the known art are described in:

[0119] “High-Performance Transparent and Flexible Triboelectric Nanogenerators Based on PDMS-PTFE Composite Films”, Gui-Zhong Li Gui-Gen Wang Da-Ming Ye Xu-Wu Zhang Zhao-Qing Lin Hai-Ling Zhou Fei Li Bao-Lin Wang Jie-Cai Han, First published: 5 Mar. 2019 https://doi.org/10.1002/aelm.201800846 and

[0120] “A high output magneto-mechano-triboelectric generator enabled by accelerated water-soluble nano-bullets for powering a wireless indoor positioning system”, Kyung-Won Lim, ab Mahesh Peddigari, in Chan Hee Park, in Ha Young Lee, b Yuho Min, to Jong-Woo Kim, to Cheol-Woo Ahn, to Jong-Jin Choi, to Byung-Dong Hahn, to Joon-Hwan Choi, to Dong-Soo Park, to Jae-Keun Hong, to Jong-Taek Yeom, to Woon-Ha Yoon, in Jungho Ryu, *c Sam Nyung Yi*b and Geon-Tae Hwang, Energy & Environmental Science, 2019.12, 666-674, https://pubs.rsc.org/en/content/articlelanding/2019/ee/c8ee03008a.

EXAMPLE 7 MAGNETORESISTIVE SENSORS

[0121] The product defined as P2 in example 2 was used to develop magnetoresistive sensors both in the wet and in the solid state. A schematic example of these sensors is illustrated in FIG. 2.

[0122] According to an embodiment, the magnetoresistive sensor has a magnetoresistive junction element 410 connecting two tracks of electrically conductive material 420 together. When the magnetoresistive junction 420 enters a magnetic field, for example, the field generated by a magnet 400, the electrical resistance of the joint changes. The change in resistance generally depends both on the distance of the magnet and on the magnetic field (B) generated by the magnet, i.e. the direction and intensity of the magnetic field.

[0123] In an embodiment, PVA and PDMS can be used as the material for the polymeric matrix of the magnetoresistive junction for the realization of the junction in the wet state and in the solid state condition.

[0124] According to an embodiment, moreover, for the two electrically conductive tracks 420 it is possible to use the product called P1 according to one or more of the variants and embodiments described in example 1.

[0125] In an embodiment, the material used for the joint is of the type defined as P5 in the previous description. In this case, the magnetic polarization of the magnetoresistive junction 410 is reversible.

[0126] In particular, the rheology of the PVA or the visco-elasticity of the PDMS allow the ferromagnetic components to orient their magnetic dipoles along the magnetic field B, and then to return to random and disordered orientation states (for example, their initial state).

[0127] In an embodiment, the two electrically conductive tracks are provided on a substrate indicated with 430.

[0128] In an experimental embodiment, the two electrically conductive tracks 420 made of the material defined as P1 are made with a surface of 1×5 cm.sup.2 and a thickness of about 80 μm, while the magnetoresistive joint 410 is provided with a surface of 1×1 cm.sup.2 and a thickness included between 100-150 μm.

[0129] Experimentally, a magnetic field is oriented parallel to the tracks 410 while the reduction of the electrical resistance caused by the alignment of the ferromagnetic components is measured.

[0130] FIG. 3a shows the magnetoresistive response of a magnetoresistive sensor as a function of the intensity of the magnetic field B, i.e. the density of the magnetic flux. The magnetoresistive response was calculated as |ΔR/R.sub.0|, where ΔR is the difference between the electrical resistance before applying the magnetic field B, and R.sub.0 is the initial electrical resistance of the sensor.

[0131] The sensor was preconditioned with 10 on-off application cycles of B for each of the different magnetic flux density values provided.

[0132] The magnetoresistive response was calculated on 10 different cycles for each magnetic flux density value. The magnetoresistive response increases by increasing the density of the magnetic flux. FIG. 3b shows the sensor's magnetoresistive response as a function of time, with the on-off cycles of application of the magnetic field performed at different frequencies between 0.5 Hz and 10 Hz. The magnetoresistive response is greater than 0.5 at the frequency. lower than 1 Hz, while they stabilize around 0.5 for a higher frequency up to 10 Hz, indicating a sensor operating response time of less than 100 ms.

[0133] Wet state sensors exhibit a faster and stronger magnetoresistive response than solid state sensors, but they must be properly encapsulated to prevent the paste from drying out.

[0134] FIG. 4 illustrates the comparison between the responses of solid-state and wet-state magnetoresistive sensors over time (up to 250 hours). The data demonstrate that the initial magnetoresistive response of wet state sensors is higher than that measured for solid state sensors. However, the magnetoresistive response of the wet state sensor begins to drop significantly after 50 hours, completely failing after 120 hours. In contrast, solid-state sensors optimally reproduce their initial magnetoresistive behavior for over 250 hours.

EXAMPLE 8 ELECTROMECHANICAL AND REED TYPE RELAYS

[0135] With reference to FIGS. 5 and 6, these show the use of the product defined P2 and described in example 2 for the construction of an electromechanical relay or a reed relay.

[0136] The P2 product described in Example 2 comprises an electrically conductive and magnetically polarizable component.

[0137] In the embodiment relating to the electromagnetic relay, an electrically conductive and magnetically polarizable junction element is indicated with 700 and constitutes the electrical connection bridge between two conductive material tracks 820 insulated from each other, which junction element 700 is alternatively movable between one contextual electrical contact position with the two tracks 720 and a spaced position and not in contact with at least one of the two tracks 820.

[0138] A magnet 730 that generates a magnetic field acts in the sense of permanently attracting the junction element 700 in the position in which it creates the electrical connection between the two tracks 720.

[0139] As shown in the figure, in this case the power supply circuit of the user 710 is closed allowing an electric current to pass through said user.

[0140] By providing a magnet 750 which generates a magnetic field of greater intensity than that of magnet 730, it is possible to move junction element 700 to the position of the left figure, i.e. in a condition of detachment from tracks 720, and therefore of opening of the circuit of user power supply 710.

[0141] In the illustrated embodiment the tracks are made on an insulating substrate 740.

[0142] The tracks 720 can be in the form of an electrically conductive film deposited on the said substrate, or of a “self-standing” material fixed on the surface of the said support.

[0143] FIG. 6 shows a reed-type relay. The structure is similar to that of the example of FIG. 5. In this case, however, magnet 750 is replaced by a resistive magnet 850 powered to attract itself and therefore detach junction element 800 from conductive tracks 820 on substrate 840.

[0144] According to FIG. 6, the reed relay has a substrate 840 on which electrically conductive tracks 820 are present. A junction element 800 for tracks 820. The user is indicated with 810.

[0145] Example 10 Electromechanical actuator, for example, valves or the like.

[0146] FIG. 7 shows an executive example of an electromechanical actuator, with particular reference to the passage for the fluid of an electrically controllable valve.

[0147] Generally, the example shown has a passage duct delimited laterally by two elements 920 which form a channel between them which is delimited on the front and rear side, for example, by a closing wall which can withstand even several years of stress.

[0148] The duct can be closed at the inlet and/or outlet ends by a shutter 900 which is obtained from the product P2, and therefore attributable to the components described in example 2.

[0149] The P2 material has electrical and magnetic functionality, in particular it is magnetically polarizable and electrically conductive. The magnetically polarizable and electrically conductive components can be chosen from one or more of the components of the examples and in the executive variants described above.

[0150] Advantageously, shutter 900 comprises a polymer matrix with characteristics of elastic deformability, or an elastomer which allows an elastic deformation.

[0151] Shutter 900 is switched to the closed condition by the magnetic field of a magnet 910 which stably maintains said shutter 900 in the undeformed and closed condition of the passage, while it is deformed by means of a polarization magnetic field generated by an electromagnet indicated with 950.

[0152] In the illustrated embodiment, the valve structure comprises a substrate 940 for supporting side walls delimiting the channel which leads to the passage opening while the opening is provided at the head ends of said walls and at said head ends the ends of the obturator are attached, which is made as a deformable crosspiece which is placed at the closure of the passage in its undeformed condition. The electrical conductivity of the valve enables integration with electrical circuits capable of providing a retroactive electrical response to the state of the valve, i.e. the closing or opening condition of the same.