METHOD OF MAKING FUNCTIONALIZED SUBSTRATES

Abstract

Functionalized substrates, methods of making functionalized substrates, and methods of using functionalized substrates are disclosed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described with reference to the appended figures, wherein:

FIG. 1 depicts exemplary method steps for making functionalized substrates of the present invention; and

FIG. 2 depicts exemplary method steps for making functionalized substrates of the present invention.

Claims

1. A method of making a functionalized substrate, the method comprises the steps of: providing a porous base substrate having interstitial and outer surfaces;imbibing the porous base substrate with a first solution to form an imbibed porous base substrate, the first solution comprising at least one grafting monomer having (a) a free-radically polymerizable group and (b) an additional functional group comprising an ethylenically unsaturated group, an epoxy group, an azlactone group, an ionic group, an alkylene oxide group, or combination thereof,exposing the imbibed porous base substrate to a controlled amount of electron beam radiation so as to form a first functionalized substrate comprising grafted species attached to the surfaces of the porous base substrate, wherein at least one of the grafted species comprises the additional functional group.

2. The method of claim 1, wherein the porous base substrate is microporous.

3. The method of claim 1, wherein the porous base substrate is selected from a porous membrane, porous non-woven web, or porous fiber.

4. The method of claim 1, wherein the porous base substrate is a microporous membrane or a nonwoven web that is hydrophobic.

5. The method of claim 1, wherein the porous base substrate is hydrophobic and the functionalized substrate is hydrophilic.

6. The method of claim 1, further comprising the step of exposing the functionalized substrate to a heat cycle at 30° C. or higher.

7. The method of claim 1, wherein the grafting monomer comprises a polyalkylene glycol di(methacrylate).

8. The method of claim 1, further comprising the steps of: imbibing the first functionalized substrate with a second solution to form a first imbibed functionalized substrate, the second solution comprising at least one grafting monomer having (a) a free-radically polymerizable group and (b) a second additional functional group comprising an ethylenically unsaturated group, an epoxy group, an azlactone group, an ionic group, an alkylene oxide group, or combination thereof,exposing the first imbibed functionalized substrate to a controlled amount of electron beam radiation so as to form a second functionalized substrate comprising grafted species attached to the surfaces of the porous base substrate, wherein at least one of the grafted species comprises the second additional functional group.

9. The method of claim 8, wherein at least one of the first or second solutions comprises a polyalkylene glycol di(meth)acrylate and at least one of the first or second solutions comprises a glycidyl(meth)acrylate, isocyanatoalkyl(meth)acrylate, or vinyl azlactone.

10. The method of claim 1, further comprising the steps of: imbibing the first functionalized substrate with a second solution to form a first imbibed functionalized substrate, the second solution comprising at least one nucleophilic compound comprising at least one nucleophilic group;exposing the first imbibed functionalized substrate to a controlled amount of heat so as to react the nucleophilic compound with the epoxy group, azlactone group, isocyanate group, or combination thereof.

11. The method of claim 10, wherein the nucleophilic compound comprises a nucleophilic group comprising at least one primary amino group, secondary amino group, hydroxy, carboxy, or combination thereof.

12. The method of claim 10, wherein the nucleophilic compound has a plurality of nucleophilic groups that react to crosslink at least two grafted species.

13. The method of claim 10, wherein the nucleophilic compound comprises at least two primary amino groups and a polyalkylene oxide group.

14. The method of claim 8, further comprising the steps of: imbibing the second functionalized substrate with a third solution to form a second imbibed functionalized substrate, the third solution comprising at least nucleophilic compound comprising at least one nucleophilic group;exposing the second imbibed functionalized substrate to a controlled amount of heat so as to react the nucleophilic compound with the epoxy group, azlactone group, isocyanate group, or combination thereof.

15. The method of claim 14, wherein the nucleophilic compound has a plurality of nucleophilic groups that react to crosslink at least two grafted species.

16. The method of claim 1, wherein the porous base substrate is a hydrophobic microporous membrane having an initial average pore size and the functionalized substrate is hydrophilic microporous membrane having a final average pore size that is larger than the initial average pore size of the porous base substrate.

17. The method of claim 16, wherein the hydrophobic microporous membrane is formed by a thermally-induced phase separation (TIPS) method.

18. The method of claim 16, wherein the hydrophobic microporous membrane comprises poly(vinylidene fluoride) formed by a thermally-induced phase separation (TIPS) method.

19. The method of claim 1, wherein the controlled amount of electron beam radiation exposure comprises a dosage of 20 kGy to 40 kGy.

20. A method of making a functionalized substrate, the method comprises the steps of: providing a porous base substrate having interstitial and outer surfaces;imbibing the porous base substrate with a first solution to form an imbibed porous base substrate, the first solution comprising at least one grafting monomer having (a) a free-radically polymerizable group and (b) an additional functional group comprising an ethylenically unsaturated group, an epoxy group, an azlactone group, an ionic group, an alkylene oxide group, or combination thereof,positioning the imbibed porous base substrate between a removable carrier layer and a removable cover layer to form a multilayer structure;exposing the multilayer structure to a controlled amount of electron beam radiation so as to form a functionalized substrate positioned between the removable carrier layer and the removable cover layer, the functionalized substrate comprising grafted species attached to the surfaces of the porous base substrate, wherein at least one of the grafted species comprises the additional functional group; andremoving the carrier layer and cover layers from the multilayer structure.