Fast-acting antimicrobial surfaces, and methods of making and using the same
An antimicrobial coating is disclosed that provides fast transport rates of biocides for better effectiveness to deactivate SARS-CoV-2 and other viruses or bacteria on common surfaces. Some variations provide an antimicrobial structure comprising: a solid structural phase comprising a solid structural material; a continuous transport phase that is interspersed within the solid structural phase, wherein the continuous transport phase comprises a solid transport material; and an antimicrobial agent contained within the continuous transport phase, wherein the solid structural phase and the continuous transport phase are separated by an average phase-separation length from about 100 nanometers to about 500 microns. The antimicrobial structure is capable of destroying at least 99.99% of bacteria and/or viruses in 10 minutes of contact. Many options are disclosed for suitable materials to form the solid structural phase, the continuous transport phase, and the antimicrobial agent.
1. An antimicrobial structure comprising:
(a) a solid structural phase comprising a solid structural material, wherein said solid structural material is a solid structural polymer selected from the group consisting of a non-fluorinated carbon-based polymer, a silicone, a fluorinated polymer, and combinations thereof;
(b) a continuous transport phase that is interspersed within said solid structural phase, wherein said continuous transport phase comprises a solid transport material, and wherein said continuous transport phase contains an antimicrobial agent and a transport-phase liquid that at least partially dissolves said antimicrobial agent; and
(c) first and second electrodes,
wherein said antimicrobial agent is electrically or electrochemically rechargeable when a voltage is applied between said first and second electrodes,
and wherein said solid structural phase and said continuous transport phase are separated by an average phase-separation length from about 100 nanometers to about 500 microns.
2. The antimicrobial structure of claim 1 , wherein said first and second electrodes are embedded within said antimicrobial structure.
3. The antimicrobial structure of claim 1 , wherein at least one of said first and second electrodes is an outer layer disposed on said antimicrobial structure.
4. The antimicrobial structure of claim 1 , wherein said first electrode is a first outer layer disposed on said antimicrobial structure, and wherein said second electrode is a second outer layer disposed on said antimicrobial structure.
5. The antimicrobial structure of claim 1 , wherein one of said first and second electrodes is integrated with a base substrate or a wall.
6. The antimicrobial structure of claim 1 , wherein at least one of said first and second electrodes has a non-planar electrode architecture.
7. The antimicrobial structure of claim 1 , wherein said electrodes are fabricated from metal grids, meshes, or perforated plates.
8. The antimicrobial structure of claim 1 , wherein said electrodes contain a catalyst.
9. The antimicrobial structure of claim 8 , wherein said catalyst is selected from the group consisting of Ti, Pt, Ru, Ir, and combinations thereof.
10. The antimicrobial structure of claim 1 , wherein said non-fluorinated carbon-based polymers are selected from the group consisting of polyalkanes, polyurethanes, polyethers, polyureas, polyesters, and combinations thereof.
11. The antimicrobial structure of claim 1 , wherein said silicones are selected from the group consisting of polydimethyl siloxane, polytrifluoropropylmethyl siloxane, polyaminopropylmethyl siloxane, polyaminoethylaminopropylmethyl siloxane, polyaminoethylaminoisobutylmethyl siloxane, and combinations thereof.
12. The antimicrobial structure of claim 1 , wherein said fluorinated polymers are selected from the group consisting of fluorinated polyols, perfluorocarbons, perfluoropolyethers, polyfluoroacrylates, polyfluorosiloxanes, polyvinylidene fluoride, polytrifluoroethylene, and combinations thereof.
13. The antimicrobial structure of claim 1 , wherein said solid transport material includes a hygroscopic solid transport polymer selected from the group consisting of poly(acrylic acid), poly(ethylene glycol), poly(2-hydroxyethyl methacrylate), poly(vinyl imidazole), poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline), poly(vinylpyrolidone), modified cellulosic polymers, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, and combinations thereof.
14. The antimicrobial structure of claim 1 , wherein said solid transport material includes a hydrophobic, non-lipophobic solid transport polymer selected from the group consisting of poly(propylene glycol), poly(tetramethylene glycol), polybutadiene, polycarbonate, polycaprolactone, acrylic polyols, and combinations thereof.
15. The antimicrobial structure of claim 1 , wherein said solid transport material includes a hydrophilic solid transport polymer with ionic charge, and wherein said ionic charge is present within said hydrophilic solid transport polymer as carboxylate groups, amine groups, sulfate groups, or phosphate groups.
16. The antimicrobial structure of claim 1 , wherein said solid transport material includes an electrolyte solid transport polymer selected from the group consisting of polyethylene oxide, polypropylene oxide, polycarbonates, polysiloxanes, polyvinylidene difluoride, and combinations thereof.
17. The antimicrobial structure of claim 1 , wherein said solid structural material is a solid structural polymer, wherein said solid transport material is a solid transport polymer, and wherein said solid structural polymer is crosslinked, via a crosslinking molecule, with said solid transport polymer.
18. The antimicrobial structure of claim 17 , wherein said crosslinking molecule includes at least one moiety selected from the group consisting of an amine moiety, a hydroxyl moiety, an isocyanate moiety, and a combination thereof.
19. The antimicrobial structure of claim 1 , wherein said transport-phase liquid is water.
20. The antimicrobial structure of claim 1 , wherein said antimicrobial agent is sodium hypochlorite and/or hypochlorous acid.
21. The antimicrobial structure of claim 1 , wherein said antimicrobial agent is hydrogen peroxide.
22. The antimicrobial structure of claim 1 , wherein said antimicrobial agent is selected from N-halamines.
23. The antimicrobial structure of claim 1 , wherein said antimicrobial structure is characterized in that said antimicrobial agent has a diffusion coefficient between 10 −16 m 2 /s and 10 −9 m 2 /s, measured at 25° C. and 1 bar, within said continuous transport phase.
24. The antimicrobial structure of claim 1 , wherein said antimicrobial structure further contains one or more protective layers.
25. The antimicrobial structure of claim 1 , wherein said antimicrobial structure is a coating, is present in a coating, or is present at a surface of a bulk object.
26. A method of charging or recharging an antimicrobial structure with an antimicrobial agent, said method comprising:
(i) providing an antimicrobial structure comprising: a solid structural phase comprising a solid structural material, wherein said solid structural material is a solid structural polymer selected from the group consisting of a non-fluorinated carbon-based polymer, a silicone, a fluorinated polymer, and combinations thereof; a continuous transport phase that is interspersed within said solid structural phase, wherein said continuous transport phase comprises a solid transport material; and first and second electrodes;
(ii) introducing an antimicrobial agent precursor to said continuous transport phase; and
(iii) applying a voltage between said first and second electrodes, wherein said antimicrobial agent precursor is electrochemically converted to an antimicrobial agent within said continuous transport phase.
27. The method of claim 26 , wherein said method initially charges said antimicrobial agent into said antimicrobial structure.
28. The method of claim 26 , wherein said method recharges said antimicrobial agent into said antimicrobial structure after a period of use.
29. The method of claim 26 , wherein in step (ii), said continuous transport phase is wet with a liquid solution containing said antimicrobial agent precursor and/or a liquid electrolyte containing said antimicrobial agent precursor.
30. The method of claim 26 , wherein said antimicrobial agent precursor is sodium chloride, and wherein said antimicrobial agent is sodium hypochlorite and/or hypochlorous acid.
31. The method of claim 26 , wherein said antimicrobial agent precursor is sodium hypochlorite and/or hypochlorous acid, and wherein said antimicrobial agent is selected from chlorine-containing N-halamines.
32. The method of claim 26 , wherein said method further comprises washing or soaking said antimicrobial structure with a salt solution and/or a pH buffer.
33. The method of claim 26 , wherein said solid structural phase and said continuous transport phase are separated by an average phase-separation length from about 100 nanometers to about 500 microns.
34. The method of claim 26 , wherein said antimicrobial agent has a diffusion coefficient between 10 −16 m 2 /s and 10 −9 m 2 /s, measured at 25° C. and 1 bar, within said continuous transport phase.
35. The method of claim 26 , wherein said first and second electrodes are embedded within said solid structural phase.
36. The method of claim 26 , wherein at least one of said first and second electrodes is an outer layer disposed on said solid structural phase.
37. The method of claim 26 , wherein said first electrode is a first outer layer disposed on said solid structural phase, and wherein said second electrode is a second outer layer disposed on said solid structural phase.
38. The method of claim 26 , wherein one of said first and second electrodes is integrated with a base substrate or a wall.
39. The method of claim 26 , wherein at least one of said first and second electrodes has a non-planar electrode architecture.
40. The antimicrobial structure of claim 1 , wherein said antimicrobial structure further comprises a particulate filler.
41. The antimicrobial structure of claim 40 , wherein said particulate filler is selected from the group consisting of silica, alumina, silicates, talc, aluminosilicates, barium sulfate, mica, diatomite, calcium carbonate, calcium sulfate, carbon, wollastonite, and combinations thereof.
42. The antimicrobial structure of claim 40 , wherein said particulate filler is surface-modified with a compound selected from the group consisting of fatty acids, silanes, alkylsilanes, fluoroalkylsilanes, silicones, alkyl phosphonates, alkyl phosphonic acids, alkyl carboxylates, alkyldisilazanes, and combinations thereof.