Gas separation membrane, method of producing gas separation membrane, gas separation membrane module, and gas separator
Provided are a gas separation membrane which has a resin layer containing a compound having a siloxane bond, in which the resin layer containing a compound having a siloxane bond satisfies Expressions 1 and 2, and at least one of gas permeability or gas separation selectivity is high under high pressure; a method of producing a gas separation membrane; a gas separation membrane module; and a gas separator. 0.9≥ A/B ≥0.63 Expression 1 B ≥1.7 Expression 2 In the expressions, A represents an O/Si ratio that is a ratio of the number of oxygen atoms relative to the number of silicon atoms contained in the resin layer containing a compound having a siloxane bond at a depth of 10 nm from the surface of the resin layer containing a compound having a siloxane bond, and B represents an O/Si ratio that is a ratio of the number of oxygen atoms relative to the number of silicon atoms in the surface of the resin layer containing a compound having a siloxane bond.
1. A gas separation membrane which satisfies any one of the following Conditions 1, 3, and 4,
Condition 1: a gas separation membrane which has a resin layer containing a compound having a siloxane bond, in which the resin layer containing a compound having a siloxane bond satisfies the following Expressions 1 and 2,
0.9 ≥A/B≥ 0.63, and Expression 1
Expression 2 B≥ 1.7 Expression 2
in Expressions 1 and 2, A is 1.15 or more and represents an O/Si ratio that is a ratio of the number of oxygen atoms relative to the number of silicon atoms contained in the resin layer containing a compound having a siloxane bond at a depth of 10 nm from the surface of the resin layer containing a compound having a siloxane bond, and B represents an O/Si ratio that is a ratio of the number of oxygen atoms relative to the number of silicon atoms in the surface of the resin layer containing a compound having a siloxane bond,
Condition 3: a gas separation membrane which has a resin layer containing a compound having a siloxane bond, in which a minimum value Si 0 of the proportion of peaks of Si 2+ and Si 3+ to peaks of all Si in ESCA depth analysis of the resin layer containing a compound having a siloxane bond is in a range of 1% to 40%, and
Condition 4: a gas separation membrane which has a resin layer containing a compound having a siloxane bond, in which positron lifetime τ3 of a third component in a case where the positron is implanted at a strength of 1 keV from the surface of the resin layer containing a compound having a siloxane bond is in a range of 3.40 to 4.20 ns.
2. The gas separation membrane according to claim 1 , which satisfies Condition 1.
3. The gas separation membrane according to claim 2 ,
wherein the compound having a siloxane bond includes at least a repeating unit represented by the following Formula (2) or a repeating unit represented by the following Formula (3),
in Formulae (2) and (3), R 11 represents a substituent, the symbol “*” represents a binding site with respect to # in Formula (2) or (3), and the symbol “#” represents a binding site with respect to * in Formula (2) or (3).
4. The gas separation membrane according to claim 2 ,
wherein the compound having a siloxane bond includes a repeating unit represented by the following Formula (1),
in Formula (1), R's each independently represent a hydrogen atom, an alkyl group having 1 or more carbon atoms, an aryl group, an amino group, an epoxy group, a fluorinated alkyl group, a vinyl group, an alkoxy group, or a carboxyl group, and n represents an integer of 2 or greater.
5. The gas separation membrane according to claim 4 ,
wherein the surface of the resin layer containing a compound having a siloxane bond includes a compound which has a siloxane bond having a repeating unit represented by Formula (1) described above and at least a repeating unit represented by the following Formula (2) or a repeating unit represented by the following Formula (3);
in Formulae (2) and (3), R 11 represents a substituent, the symbol “*” represents a binding site with respect to # in Formula (2) or (3), and the symbol “#” represents a binding site with respect to * in Formula (2) or (3).
6. The gas separation membrane according to claim 2 ,
wherein the ratio of the number of carbon atoms relative to the number of silicon atoms in the surface of the resin layer containing a compound having a siloxane bond is 1.6 or less.
7. The gas separation membrane according to claim 2 ,
wherein B is 1.95 or greater, and
B represents an O/Si ratio that is a ratio of the number of oxygen atoms relative to the number of silicon atoms in the surface of the resin layer containing a compound having a siloxane bond.
8. The gas separation membrane according to claim 2 ,
wherein AB is 0.65 or greater, and
A represents an O/Si ratio that is a ratio of the number of oxygen atoms relative to the number of silicon atoms contained in the resin layer containing a compound having a siloxane bond at a depth of 10 nm from the surface of the resin layer containing a compound having a siloxane bond, and
B represents an O/Si ratio that is a ratio of the number of oxygen atoms relative to the number of silicon atoms in the surface of the resin layer containing a compound having a siloxane bond.
9. The gas separation membrane according to claim 2 , further comprising:
a layer which contains a polyimide compound.
10. The gas separation membrane according to claim 2 ,
wherein the thickness of the layer containing a polyimide compound is in a range of 0.03 to 0.3 μm.
11. The gas separation membrane according to claim 2 ,
wherein the thickness of the resin layer which contains a compound having a siloxane bond is in a range of 0.1 to 5 μm.
12. The gas separation membrane according to claim 2 ,
wherein the resin layer containing a compound having a siloxane bond includes a compound having a repeating unit that contains at least silicon atoms, oxygen atoms, and carbon atoms.
13. The gas separation membrane according to claim 2 , further comprising:
a support.
14. The gas separation membrane according to claim 2 ,
wherein the gel fraction of the gas separation membrane is 45% or greater.
15. The gas separation membrane according to claim 1 which satisfies Condition 3.
16. The gas separation membrane according to claim 15 ,
wherein a difference Δ1 between a ratio Si 10 of peaks of Si 2+ and Si 3+ relative to peaks of all Si at a depth of 10 nm from the position having a minimum value Si 0 of the proportion of peaks of Si 2+ and Si 3+ relative to peaks of all Si and the minimum value Si 0 of the proportion of peaks of Si 2+ and Si 3+ relative to peaks of all Si in ESCA depth analysis of the resin layer containing a compound having a siloxane bond is in a range of 50% to 90%.
17. The gas separation membrane according to claim 15 ,
wherein a difference Δ2 between a ratio Si 20 of peaks of Si 2+ and Si 3+ relative to peaks of all Si at a depth of 20 nm from the position having the minimum value Si 0 of the proportion of peaks of Si 2+ and Si 3+ relative to peaks of all Si and the minimum value Si 0 of the proportion of peaks of Si 2+ and Si 3+ relative to peaks of all Si in ESCA depth analysis of the resin layer containing a compound having a siloxane bond is in a range of 55% to 90%.
18. The gas separation membrane according to claim 15 ,
wherein the thickness of the resin layer containing a compound having a siloxane bond is in a range of 150 to 900 nm.
19. The gas separation membrane according to claim 15 , further comprising:
a support.
20. The gas separation membrane according to claim 1 which satisfies Condition 4.
21. The gas separation membrane according to claim 20 ,
wherein relative strength 13 of the third component in a case where the positron is implanted at a strength of 1 keV from the surface of the resin layer containing a compound having a siloxane bond is in a range of 13% to 41%.
22. The gas separation membrane according to claim 20 ,
wherein when positron lifetime τ3 of the third component in a case where the positron is implanted at a strength of 1 keV from the surface of the resin layer containing a compound having a siloxane bond is set to X and positron lifetime τ3 of the third component in a case where the positron is implanted at a strength of 3 keV from the surface of the resin layer containing a compound having a siloxane bond is set to Y, the expression of 0.88≤X/Y≤0.99 is satisfied.
23. The gas separation membrane according to claim 20 , further comprising:
a layer which contains a polyimide compound.
24. The gas separation membrane according to claim 23 ,
wherein the thickness of the layer containing a polyimide compound is in a range of 0.03 to 0.3 μm.
25. The gas separation membrane according to claim 20 ,
wherein the thickness of the resin layer which contains a compound having a siloxane bond is in a range of 0.1 to 5 μm.
26. The gas separation membrane according to claim 20 ,
wherein the resin layer containing a compound having a siloxane bond includes a compound having a repeating unit that contains at least silicon atoms, oxygen atoms, and carbon atoms.
27. The gas separation membrane according to claim 20 , further comprising:
a support.
28. A gas separation membrane module comprising:
the gas separation membrane according to claim 1 .
29. A gas separator comprising:
the gas separation membrane module according to claim 28 .
30. A method of producing a gas separation membrane which satisfies the following Condition P1 or P4,
Condition P1: a method of producing a gas separation membrane including an oxygen atom permeating treatment of allowing oxygen atoms to permeate into a resin layer precursor containing a compound having a siloxane bond,
wherein the oxygen atom permeating treatment is a plasma treatment using carrier gas having an oxygen flow rate of 10 cm 3 (STP)/min or greater at an input power of 75 W or greater, and
Condition P4: a method of producing a gas separation membrane including an oxygen atom permeating treatment of allowing oxygen atoms to permeate into a resin layer precursor containing a compound having a siloxane bond,
wherein the oxygen atom permeating treatment is a plasma treatment using carrier gas having an oxygen flow rate of 45 cm 3 (STP)/min or greater and using anode coupling at an input power of 75 W or greater.
31. The method of producing a gas separation membrane according to claim 30 which satisfies Condition P1.
32. The method of producing a gas separation membrane according to claim 31 ,
wherein the resin layer containing a compound having a siloxane bond includes a compound having a repeating unit that contains at least silicon atoms, oxygen atoms, and carbon atoms.
33. The method of producing a gas separation membrane according to claim 31 ,
wherein the resin layer containing a compound having a siloxane bond is formed on a support.
34. A gas separation membrane which is produced using the method of producing a gas separation membrane according to claim 31 .
35. The method of producing a gas separation membrane according to claim 30 which satisfies Condition P4.
36. The method of producing a gas separation membrane according to claim 35 ,
wherein the resin layer containing a compound having a siloxane bond includes a compound having a repeating unit that contains at least silicon atoms, oxygen atoms, and carbon atoms.
37. The method of producing a gas separation membrane according to claim 35 ,
wherein the resin layer containing a compound having a siloxane bond is formed on a support.
38. The method of producing a gas separation membrane according to claim 30 , wherein the wattage of plasma processing is 75 W or more and the time for irradiation with radiation of plasma processing is 30 seconds or less.
39. The gas separation membrane according to claim 1 , wherein the value of A is 1.3 or more.
40. The method of producing a gas separation membrane according to claim 30 , wherein the wattage of plasma processing is 110 W or more and the material of the resin layer containing a compound having a siloxane bond is polydimethylsiloxane (PDMS).