Microporous articles with a three-dimensional porous network of acid-sintered interconnected silica nanoparticles and methods of making the same

A method of making a multilayer article comprising:

• a) providing a first microfiltration membrane layer, the first microfiltration membrane layer having a first major surface and a second major surface disposed opposite the first major surface;
• and
• b) forming a first silica layer on the first major surface, comprising a polymeric binder and a plurality of acid-sintered interconnected silica nanoparticles arranged to form a continuous three-dimensional porous network.

A multizone article comprising:

• a) a first porous zone comprising first average pore size;
• and
• b) a second porous zone integral with the first porous zone and having a second average pore size, the second porous zone comprising a polymeric binder and a plurality of acid-sintered interconnected silica nanoparticles arranged to form a continuous three-dimensional porous network.