Laminated bilayer membrane

From a materials science perspective, the SC is a laminated composite membrane comprised of two distinct domains, specifically, proteins (corneocyte cells with embedded keratin bundles) and lipid bilayers. Corneocyte cells have covalently attached lipids, which makes them compatible with the surrounding lipid matrix. In addition, corneocytes in different layers are held together by protein staples called desmosomes. SC has been designed to exfoliate dead cells in an orderly fashion where the upper layers come off in a layer-by-layer fashion. For this to happen, the desmosomes have to be cleaved by proteolytic enzymes in the SC as the cells approach the outermost layers. 

Based on the difference in the melting point of PE and PP, thermal shutdown separators can be made by laminating different PE and PP layers into a multiplayer membrane. In shutdown membrane, one or more PE layers serve as shutdown and at least one PP layer as the mechanically dimensional support. Typically, the PE-PP bilayer [14,29] and PP-PE-PP trilayer [27, 30-36] designs have been widely adopted... 

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