Patent ID: 8365925

Claim:
A porous filter medium comprising fibers of a molecularly self-assembling material having a molecular weight below 12,000 grams/mole, coated onto a porous, nonwoven web of fibers, the porous nonwoven web having a spaced-apart entrance face and exit face and defining a plurality of pores therein, the porous nonwoven web having a mean flow pore size of from about 0.1 micrometer (μm) to about 90 μm according to ASTM procedure E 1294-89, “Standard Test Method for Pore Size Characteristics of Membrane Filters Using Automated Liquid Porosimeter,” wherein the molecularly self-assembling material comprises repeat units of Formula I: and at least one second repeat unit that is Formula II, Formula III, or Formula IV: or combinations thereof wherein: R is at each occurrence, independently a C 2 -C 20 non-aromatic hydrocarbylene group, a C 2 -C 20 non-aromatic heterohydrocarbylene group, or a polyalkylene oxide group having a group molecular weight of from about 100 grams per mole to about 5000 grams per mole; R 1 at each occurrence independently is a bond or a C 1 -C 20 non-aromatic hydrocarbylene group; R 2 at each occurrence independently is a C 1 -C 20 non-aromatic hydrocarbylene group; R N is —N(R 3 )—Ra—N(R 3 )—, where R 3 at each occurrence independently is H or a C 1 -C 6 alkylene and Ra is a C 2 -C 20 non-aromatic hydrocarbylene group, or R N is a C 2 -C 20 heterocycloalkyl group containing the two nitrogen atoms, wherein each nitrogen atom is bonded to a carbonyl group according to formula (III) above; n is at least 1 and has a mean value less than 2; and w represents the ester mol fraction of Formula I, and x, y and z represent the amide or urethane mole fractions of Formulas II, III, and IV, respectively, where w+x+y+z=1, and 0<w<1, and at least one of x, y and z is greater than zero but less than 1.