Process for making microporous membranes having gel-filled pores, and separations methods using such membranes

A method of modifying a hydrophobic microporous membrane, by providing a stabilized gelled liquid membrane immobilized in the pores of a microporous membrane having properties for enabling separations at high pressure drops across the membrane while substantially precluding loss of the liquid membrane by rejection from the microporous matrix, comprising the steps of:

• (a) treating the membrane with a surfactant;
• (b) draining excess surfactant from the membrane;
• (c) drying the membrane;
• (d) preparing an aqueous solution of at least one polyol and at least one compound selected from the group consisting of divinyl sulfone and divinyl sulfone precursors;
• (e) treating the membrane with the aqueous solution;
• (f) removing aqueous solution from the exterior of the membrane by washing the membrane with water;
• (g) crosslinking the aqueous solution in the pores of the membrane;
• and
• (h) washing the membrane with water, to yield a hydrophilic membrane having pores filled with a water-soluble gel sufficient to provide said properties.