Composite membrane with integral rim

#1. Field of the Invention

#The present invention relates to composite membranes, methods for making composite membranes and applications of the composite membranes. The composite membranes include a porous support structure and one or more active layers disposed within the pores of the support structure.

#2. Description of Related Art

#FIG. 1 illustrates a schematic representation of the structure of a composite membrane according to an embodiment of the present invention.

#FIG. 2 is a schematic representation of composite membrane according to the prior art (top image) and various embodiments of the present invention.

#FIG. 3 illustrates a method for the fabrication of a symmetric composite membrane according to an embodiment of the present invention, where an active layer is formed after the separation of the support membrane from Al.

#The present invention is directed to a composite membrane, such as for the selective separation of gas species. The composite membrane 100, shown in FIG. 1, includes a porous support membrane (or support structure) 102 and one or more active layers 110 disposed within the pore channels 108, which extend through the support structure between the first major surface 104 and the second major surface 106 of the support structure 102. The active layer 110 can advantageously be permselective for one or more gas species, such as H2.

#In one embodiment, the porous support structure 102 is an anodic aluminum oxide (AAO) substrate. AAO advantageously has substantially parallel and uniform pore channels 108 extending through the thickness of the AAO substrate that are essentially the same diameter along the pore length, including at the location of the active layer. The pore diameter of the pore channels can be at least about 1 nm, such as at least about 5 nm, and can range up to about 1000 nm, such as not greater than about 300 nm. Such support structures where the pores have a substantially uniform diameter through the thickness of the support are referred to herein as symmetric pore membranes 100 shown in FIG. 2.

#The thickness of the support structure 102 can be at least about 0.1 μm, such as at least about 10 μm, and can range up to about 500 μm, such as up to about 200 μm. In one embodiment, the composite membrane is a free-standing membrane and the support structure thickness is from about 10 μm to about 500 μm. In another embodiment, the composite membrane is a membrane with Al rim 112, such as one that is attached to a peripheral edge of the support 102, as is illustrated in FIG. 1, and is further illustrated in FIG. 5. The thickness of the supported structure can be at least about 0.1 μm and not greater than about 200 μm.