According to the official website of Medical Education Network, composite membrane belongs to passive medical treatment. Passive medical devices are medical devices that do not rely on electricity or other sources of energy, but rely on the body's own energy or external environmental energy to fulfill their medical role. Composite film is usually made of a variety of materials composite, such as polyurethane, polyethylene, polyvinyl chloride, etc., mainly used for packaging, storage and transportation of medical supplies, medicines and so on. Composite films do not possess energy per se, but play an important auxiliary role in the medical process. Therefore, composite film belongs to passive medical.
The materials of composite membranes include any possible combination of materials, such as ceramic membranes overlaid on metal oxides or aromatic polyamide films overlaid on polysulfone microporous membranes, whose flat or rolled membranes are reinforced with nonwovens to support the compression resistance of the microporous membranes, whereas hollow fiber membranes do not need to be.