Membrane structure and method of making
A membrane structure is provided. The membrane structure includes a first layer having a plurality of interconnected pores; and a second layer disposed on the first layer. The second layer has a plurality of unconnected pores. Each of the unconnected pores is in fluid communication with at least one of the interconnected pores of the first layer. A method of making a membrane structure is provided. The method includes the steps of providing a first layer having a plurality of interconnected pores; and disposing a second layer on the first layer. Disposing a second layer includes depositing a conducting layer on the first layer; and anodizing the conducting layer to convert the conducting layer into a porous layer.
1. A method comprising:
providing a first layer having a plurality of interconnected pores; and
disposing a second layer on the first layer,
wherein disposing a second layer comprises depositing a conducting layer on the first layer;
coating the conducting layer with a protective layer on a surface opposite to the porous first layer; and
anodizing the conducting layer to convert the conducting layer into a porous layer.
2. The method of claim 1 , wherein the conducting layer is anodized in an acid electrolyte through the porous first layer.
3. A method comprising:
providing a first layer having a plurality of interconnected pores;
depositing a conducting layer on the first layer;
protecting the conducting layer with a mask;
anodizing the conducting layer in an acid electrolyte through the porous first layer to convert the conducting layer into a first porous sublayer with a particular pore dimension; and
altering anodization current or anodization voltage to obtain another sublayer with pores having a different dimension than the pores of the first sublayer.