the present invention is a one - piece construction sub - micronic filter media capable of high volume filtration of sub - micronic sized particulate from fluids without the addition of wetting agents , solvents , added electrical charge enhancers , or elevated pressure differentials , which includes a continuous matrix having an initial micron rating of from about 1 to about 5 microns . the continuous matrix is impregnated with a hydrophilic terpolymer by step - wise addition of low viscosity terpolymerization mixture including 10 % to 14 % by weight of a polymer which includes at least one of alkyl acrylate and alkyl methacrylate and acrylic acid . the terpolymeric mixture also includes 17 to about 20 % by weight of polyethyleneimine and urea solution , from about 7 to about 10 % ammonia and from about 2 to about 6 % by weight epoxy resin . the polymerization mixture has a solids content of from about 16 to about 20 % by weight prior to polymerization . the step - wise addition by which the matrix is impregnated includes saturating the matrix material with the terpolymeric mixture followed by compressing the saturated material and repeating the saturation compressing at least one additional time followed by drying the saturated matrix .