Patent Number: 
Section: claims

1. A device (100; 200; 300; 400) comprising a sealed cavity (210) containing n volumes of fluids (80, 87; 200, 230; 320, 330, 332; 420, 422, 430, 432), where n is an integer and n□2, each volume of fluid being substantially immiscible with every contiguous volume of fluid, the cavity (210) being defined by an interior surface divided into n continuous areas (60, 170; 260, 270; 360, 362, 370; 460, 462, 470, 472), each continuous area corresponding to and being in contact with a respective one of the volumes of fluid, the wettability of each area being such that each volume of fluid preferentially adheres to the corresponding continuous area rather than any one of the continuous areas adjacent to the corresponding area. 2. A device as claimed in claim 1, wherein at least one of said continuous areas comprises an electrode (42; 242) covered by an electrically insulating layer (50; 270). 3. A device as claimed in claim 1 or claim 2, wherein at least one of said continuous areas comprises the surface of an electrode (41; 260). 4. A device as claimed in any one of the above claims, wherein n=2. 5. A device as claimed in any one of the above claims, wherein each of said fluids is a liquid (80, 87; 220, 230; 320, 332; 420, 422, 430, 432). 6. A device as claimed in any one of claims 1 to 4, wherein at least one of said fluids is a gas or vapour. 7. A device as claimed in any one of the above claims, wherein each fluid (80, 87; 220, 230; 320, 332; 420, 422, 430, 432) has a substantially similar density. 8. A method of manufacturing a device (50, 87; 220, 230; 320, 332; 420, 422, 430, 432), the method comprising:providing a cavity (210) having an interior surface divided into n continuous areas (60, 170; 260, 270; 360, 362, 370; 460, 462, 470, 472), where n is an integer and n□2;filling the cavity with n volumes of fluid (80, 87; 220, 230; 320, 332; 420, 422, 430, 432), each volume of fluid being substantially immiscible with every contiguous volume of fluid such that each continuous area corresponds to and is in contact with a respective one of the volumes of fluid; andsealing the cavity, wherein the wettability of each area is such that each volume of fluid preferentially adheres to the corresponding continuous area rather than any one of the continuous areas adjacent to the corresponding area.