ACTIVE PROTECTION

Abstract

A method of operating a membrane is provided. The membrane comprises: a porous layer; a first electrically conductive layer located on a first side of the porous layer; and a second electrically conductive layer located on a second side of the porous layer. When an electric voltage is applied between the first and second electrically conductive layer across the porous layer, the membrane prevents moisture intrusion from a first surface of the membrane towards a second surface of the membrane. The method comprises applying an electric voltage between the first and second electrically conductive layer across the porous layer to prevent moisture intrusion from the first surface of the membrane towards the second surface of the membrane when it is desired to prevent moisture intrusion from the first surface towards the second surface. A membrane system for performing the method is also provided.

Claims

1. A method of operating a membrane, the membrane comprising: a porous layer; a first electrically conductive layer located on a first side of the porous layer; and a second electrically conductive layer located on a second side of the porous layer; and wherein, when an electric voltage is applied between the first and second electrically conductive layer across the porous layer, the membrane prevents moisture intrusion from a first surface of the membrane towards a second surface of the membrane, and wherein the method comprises applying an electric voltage between the first and second electrically conductive layer across the porous layer to prevent moisture intrusion from the first surface of the membrane towards the second surface of the membrane when it is desired to prevent moisture intrusion from the first surface towards the second surface.

2. A method according to claim 1, wherein the method comprises applying an electric voltage between the first and second electrically conductive layer across the porous layer to prevent moisture intrusion from the first surface of the electroosmotic membrane towards the second surface of the electroosmotic membrane when a certain condition is sensed.

3. A method according to claim 1 or 2, wherein the method comprises sensing a condition.

4. A method according to claim 3, wherein the condition is a condition in a first environment which faces the first electrically conductive layer.

5. A method according to claim 2, 3 or 4, wherein the condition is one or more of humidity, temperature, conductivity, impedance, detection of water, moisture and/or rain, the weather, acceleration, deceleration, speed, orientation, pressure.

6. A method according to any of claims 2 to 5, wherein the condition is sensed by a user and the electric voltage is switched on manually.

7. A method according to any of claims 2 to 6, wherein the condition is sensed by one or more sensors.

8. A method according to claim 7, wherein the sensor(s) comprises one or more of a humidity sensor, temperature sensor, moisture sensor, accelerometer, magnetometer, proximity sensor, pressure sensor, chemical sensor.

9. A method according to claim 7 or 8, wherein the one or more of the sensor(s) is provided by the membrane itself.

10. A method according to any preceding claim, wherein the voltage is automatically applied in response to a signal from a sensor.

11. A method according to any preceding claim, wherein the membrane is an electroosmotic and/or electrokinetic membrane.

12. A method according to any preceding claim, wherein the membrane comprises, is part of a device that comprises, and/or is connected to a device that comprises a power source, a controller, and/or one or more sensors.

13. A method according to claim 12, wherein the power source, controller, and/or one or more sensors are provided by an external portable consumer device.

14. A method according to any preceding claim, wherein the mechanism for preventing water ingress is electrostatic repulsion, electroosmotic pressure with zero electroosmotic flow, and/or electroosmotic flow.

15. A method according to any preceding claim, wherein the first electrically conductive layer has a surface that is hydrophobic, and wherein the hydrophobic surface is the surface that is furthest from the porous layer.

16. A method according to any preceding claim, wherein the porous layer has pores smaller than 500 nm.

17. A method according to any preceding claim, wherein the porous layer is a polymer porous layer.

18. A method according to any preceding claim, wherein the porous layer has a negative surface charge when wetted.

19. A method according to any preceding claim, wherein the voltage is applied to prevent intrusion of rain water.

20. A method according to any preceding claim, wherein the membrane is used in clothing.

21. A method according to any preceding claim, wherein the membrane is used in a building.

22. A method according to any preceding claim, wherein the membrane is used as a valve in microfluidic system or a vent.

23. A membrane system comprising: a membrane comprising: a porous layer; a first electrically conductive layer located on a first side of the porous layer; and a second electrically conductive layer located on a second side of the porous layer; a circuit for applying an electric voltage between the first and second electrically conductive layer across the porous layer; and a sensor for identifying a condition when it is desired to prevent moisture intrusion from the first surface towards the second surface; wherein the circuit is controlled based on an output from the sensor, and wherein when an electric voltage is applied between the first and second electrically conductive layer across the porous layer, the membrane prevents moisture intrusion from the first surface of the membrane towards the second surface of the membrane.

24. A membrane system according to claim 23, wherein the sensor comprises one or more of a humidity sensor, temperature sensor, moisture sensor, accelerometer, magnetometer, proximity sensor, pressure sensor, chemical sensor.

25. A membrane system according to claim 23 or 24, wherein the one or more of the sensors is provided by the membrane itself.

26. A membrane system according to claim 23, 24 or 25, wherein the voltage is automatically applied in response to a signal from a sensor.

27. A membrane system according to any of claims 23 to 26, wherein the membrane is an electroosmotic and/or electrokinetic membrane.

28. A membrane system according to any of claims 23 to 27, wherein the membrane comprises, is part of a device that comprises, and/or is connected to a device that comprises a power source, a controller, and/or the one or more sensors.

29. A membrane system according to claim 28 wherein the power source, controller, and/or one or more sensors are provided by an external portable consumer device.

30. A membrane system according to any of claims 23 to 29, wherein the first electrically conductive layer has a surface that is hydrophobic, and wherein the hydrophobic surface is the surface that is furthest from the porous layer.

31. A membrane system according to any of claims 23 to 30, wherein the porous layer has pores smaller than 500 nm.

32. A membrane system according to any of claims 23 to 31, wherein the porous layer is a polymer porous layer.

33. A membrane system according to any of claims 23 to 32, wherein the porous layer has a negative surface charge when wetted.

34. A membrane system according to any of claims 23 to 33, wherein the membrane is part of an item of clothing.

35. A membrane system according to any of claims 23 to 33, wherein the membrane is provided in a building.

36. A membrane system according to any of claims 23 to 33, wherein the membrane is a valve in microfluidic system or a vent.

37. A membrane system of any of claims 23 to 36, wherein the membrane is operated according to the method of any of claims 1 to 22.

38. A method according to any of claims 1 to 22, wherein the membrane is the membrane that is part of the membrane system of any of claims 22 to 37.

Description

[0083] Certain preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0084] FIG. 1 is a schematic of a system incorporating an active membrane.

[0085] FIG. 1 shows a system 1 with a porous membrane 2 that comprises a porous layer 3; a first porous electrically conductive layer 4 located on a first side of the porous layer 3; and a second porous electrically conductive layer 6 located on a second side of the porous layer 3.

[0086] When an electric voltage is applied between the first and second electrically conductive layers 4, 6 across the porous layer 3, the membrane 2 prevents moisture intrusion from a first surface of the membrane 2 (i.e. the side on which the first conductive layer 4 is located) towards a second surface of the membrane 2 (i.e. the side on which the second conductive layer 6 is located).

[0087] The membrane 2 may be operated so that an electric voltage is applied between the first and second electrically conductive layers 4, 6 across the porous layer 3 to prevent moisture intrusion from the first surface of the membrane 2 towards the second surface of the membrane 2 when it is desired to prevent moisture intrusion from the first surface towards the second surface.

[0088] The system comprises a circuit 8 that allows the supply of electric voltage across the porous membrane 2. The circuit 8 is connected to a power source 10.

[0089] The power source 10 may be connected to a controller 12. The controller 12 may control the power source 10 so that an electric voltage is applied between the first and second electrically conductive layers 4, 6 across the porous layer 3 to prevent moisture intrusion from the first surface of the membrane 2 towards the second surface of the membrane 2 when it is desired to prevent moisture intrusion from the first surface towards the second surface.

[0090] This may be achieved by a user determining when it is desired to prevent moisture intrusion from the first surface towards the second surface and applying a voltage across the membrane 2 using the circuit 8 and power source 10 to prevent the moisture intrusion. The user may cause the application of a voltage across the membrane 2 using the power source 10 and/or the controller 12. The control may be direct or remote, such as from an external device 14.

[0091] The system 1 may alternatively or additionally be set up as shown in FIG. 1 to allow automatic application of a voltage across the membrane 2 when it is desired to prevent moisture intrusion from the first surface towards the second surface.

[0092] The system 1 may comprise a sensor 16 for detecting when it is desired to prevent moisture intrusion from the first surface towards the second surface.

[0093] The sensor 16 may provide an input to the controller 12 that allows it to be determined when a condition has occurred that means that it is desired to prevent moisture intrusion from the first surface towards the second surface.