Microporous filter membrane, method of making microporous filter membrane and separator employing microporous filter membranes
First Claim
1. A method for making a monolithic polymeric filter membrane comprising at least a filter layer including micron-scale precision-shaped pores and a support layer including a precision-shaped support structure for the filter layer, the method comprising:
- providing a polymeric film having first and second sides;
forming the filter membrane layer by removing selected material from the first side of the polymeric film to define the precision-shaped micron-scale pores of the filter layer; and
forming the support structure layer by removing selected material from the second side of said polymeric film to define the precision-shaped porous support structure, the pores communicating with the porous support structure to allow the passage of filtrate therethrough, and further comprisingat least one of said filter layer and support layer being formed by;
providing a polymeric film that is of polyimide materialapplying a metallic film to one surface of said polyimide film,applying a photoresist material to said metallic film,creating a first pattern on said photoresist layer to define micron scale pores or support structure and removing selected material from said photoresist layer;
removing material from said metallic film in the areas where said photoresist material has been removed; and
removing selected material from the polyimide film in the areas where the metallic film has been removed to define the pores or support structure;
removing any remaining photoresist material and the metallic film from the polyimide film.
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Abstract
A filter membrane, methods of making such filter membrane and apparatus employing such filter membrane are disclosed, in which the filter membrane is a monolithic polymeric membrane that includes a polymeric filter layer including a micron-scale precision-shaped pores and a polymeric support layer that has a precision-shaped porous support structure for the filter layer. Several methods are disclosed for making such a membrane using micromachining techniques, including lithographic, laser ablation and x-ray treatment techniques. Several filter apparatus employing such a membrane are also disclosed.
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Citations
23 Claims
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1. A method for making a monolithic polymeric filter membrane comprising at least a filter layer including micron-scale precision-shaped pores and a support layer including a precision-shaped support structure for the filter layer, the method comprising:
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providing a polymeric film having first and second sides; forming the filter membrane layer by removing selected material from the first side of the polymeric film to define the precision-shaped micron-scale pores of the filter layer; and forming the support structure layer by removing selected material from the second side of said polymeric film to define the precision-shaped porous support structure, the pores communicating with the porous support structure to allow the passage of filtrate therethrough, and further comprising at least one of said filter layer and support layer being formed by; providing a polymeric film that is of polyimide material applying a metallic film to one surface of said polyimide film, applying a photoresist material to said metallic film, creating a first pattern on said photoresist layer to define micron scale pores or support structure and removing selected material from said photoresist layer; removing material from said metallic film in the areas where said photoresist material has been removed; and removing selected material from the polyimide film in the areas where the metallic film has been removed to define the pores or support structure; removing any remaining photoresist material and the metallic film from the polyimide film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for making a monolithic polymeric filter membrane of a predetermined thickness, the filter membrane comprising at least one filter layer with micron-scale precision-shaped pores and a support layer including a precision-shaped support structure for said filter layer, the method comprising:
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providing a substrate; spinning a first polyimide layer onto the substrate; applying a metal layer to the first polyimide layer; applying photoresist to the metal layer; developing the photoresist to define a first pattern of one of the micron-scale pores or support structure; transferring the first pattern from said photoresist to said metal layer; transferring the first pattern from the metal layer to said first polyimide layer so as to create one of said micron-scale pores or said support structure; sequentially removing the photoresist and the metal layer; spinning a second polyimide layer onto the first layer polyimide so as to create an interface therebetween; creating a second pattern on the second polyimide layer to define the other of the micron-scale pores or the support structure; removing selected material from the second polyimide layer to define the other of the micron-scale pores or support structure; curing the first and second polyimide layers so as to remove the interface therebetween and create a monolithic filter layer-support structure; and removing the integral filter layer-support structure from said substrate. - View Dependent Claims (23)
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Specification