The present invention relates to a method for manufacturing an asymmetric polyvinlylidenefluoride (PVDF)
hollow fiber membrane, which enables effective mixing of PVDF and a
diluent without using separate inorganic
fine powder, such as silica; in which a PVDF
hollow fiber membrane is manufactured using a thermally induced phase
separation method having an
advantage of allowing easy obtaining of a separation membrane of consistent quality due to a key factor in controlling the phase separation in the two-substance mixture
system of the
polymer and the
diluent being temperature, which is a manufacturing variable that is relatively simple and easy to control; in which a technique is applied for producing a
temperature difference between the outer and the inner surfaces of a PVDF hollow
fiber, and therefore, finally an asymmetric structure is expressed in which the inner surface side and the outer surface side of the PVDF hollow
fiber have mutually different pore sizes and distributions; and which, even when an extraction process and a drawing process are applied, achieves a higher tensile strength and a larger average pore size, and thus higher
porosity and water permeability than conventional hollow
fiber membranes, since inorganic
fine powder is not included. The asymmetric PVDF
hollow fiber membrane has a pore symmetry index, defined as the ratio between the pore area on the outer surface and the pore area on the inner surface, of 0.1-0.8 and has superior water permeability and tensile strength unlike a PVDF separation membrane manufactured by the existing method.