Gas Separation Membranes
A gas separation membrane comprising the following layers: (i) a porous support layer; and (ii) a discriminating layer comprising groups of the Formula (1): M—(O—) x , wherein: M is a metal or metalloid atom; O is an oxygen atom; and x has a value of at least 4; optionally (iii) a layer which comprises a fluorinated polymer; and optionally (iv) optionally a protective layer; wherein: (a) the porous support layer (i) comprises less than 10 mg/m 2 of monovalent metal ions; (b) the discriminating layer (ii) comprises a surface comprising at least 10 atomic % of M of Formula (1) groups, wherein M is as hereinbefore defined; and (c) when layer (iii) is present, layer (ii) is located between layers (i) and (iii).
1 - 23 . (canceled)
24 . A gas separation membrane
comprising the following layers:
(i) a porous support layer comprising a porous support material and a polysiloxane gutter layer (GL) and/or a precursor layer comprising a crosslinkable polysiloxane polymer;
(ii) a discriminating layer formed by plasma treatment of the surface of said polysiloxane gutter layer (GL) and/or precursor layer comprising groups of the Formula (1):
M—(O—) x Formula (1)
wherein:
M is a metal or metalloid atom;
O is an oxygen atom; and
x has a value of at least 4;
optionally (iii) a layer which comprises a fluorinated polymer; and
optionally (iv) optionally a protective layer;
wherein:
(a) the porous support layer (i) comprises at least 0.1 mg/m 2 and less than 10 mg/m 2 of monovalent metal ions;
(b) the discriminating layer (ii) comprises a surface comprising at least 10 atomic % of M of Formula (1) groups, wherein M is as hereinbefore defined; and
(c) when layer (iii) is present, layer (ii) is located between layers (i) and (iii).
25 . The gas separation membrane according to claim 24 wherein layer (ii) further comprises one or more compounds of Formula (2):
M—(O—) z Formula (2)
wherein:
M is a metal or metalloid atom;
O is an oxygen atom; and
z has a value of 1, 2 or 3.
26 . The gas separation membrane according to claim 24 wherein each M independently is silicon, titanium, zirconium or aluminium.
27 . The gas separation membrane according to claim 24 wherein the discriminating layer comprises a surface comprising less than 50 atomic % of M of Formula (1) groups.
28 . The gas separation membrane according to claim 24 wherein M is silicon and the discriminating layer comprises a surface comprising 10 to 30 atomic % of M of Formula (1) groups.
29 . The gas separation membrane according to claim 24 wherein the gutter layer is located between the support layer and the resin precursor layer and the resin precursor layer is located between the gutter layer and layer (ii).
30 . The gas separation membrane according to claim 24 wherein layer (iii) has an average thickness of 1 to 150 nm.
31 . The gas separation membrane according to claim 24 wherein layer (ii) has been formed by a process comprising use of atmospheric glow discharge plasma.
32 . The gas separation membrane according to claim 24 wherein layer (iv) is present and comprises a polysiloxane.
33 . A gas separation module comprising a gas separation membrane according to claim 24 .
34 . A method of using a gas separation membrane according to claim 24 for separating gases and/or for purifying a feed gas.
35 . A process for forming a gas separation membrane according to claim 24 .
36 . The process according to claim 35 wherein the discriminating layer (ii) is formed by a plasma deposition process using an atmosphere comprising air or oxygen.
37 . A method of using a gas separation module according to claim 33 for separating gases and/or for purifying a feed gas.