Gas plasma polymerized permselective membrane

Claim 3

The method according to claim 1 wherein the porous substrate is in the form of a hollow fiber, film, sheet, tube, flat plate or wall member of a device.

Claim 4

The method according to claim 2 wherein the glow discharge is induced by means of a radiofrequency discharge.

Claim 5

The method according to claim 2 wherein the permselective composite membrane has an oxygen permeability of at least about 1.5×10 -4 cm 3 /cm 2 -sec-cmHg and an oxygen/nitrogen selectivity of greater than 2.3.

Claim 6

The method according to claim 4 wherein the fully alkylated disiloxane consists essentially of hexamethyl disiloxane.

Claim 7

The method according to claim 2 wherein the porous substrate is brought into contact a multiple number of times with the gas plasma.

Claim 10

The method according to claim 7 wherein the glow discharge is induced by means of a radiofrequency discharge.

Claim 11

The method according to claim 7 wherein the disiloxane is present in the gaseous blend at a partial pressure of 0.01 to 1.5 Torr.

Claim 12

The method according to claim 9 wherein the oxygen is at a partial pressure ratio of 0.1 to 2.0 relative to the disiloxane.

Claim 13

The method according to claim 10 wherein oxygen is added to the gaseous blend in the form of air.

Claim 14

A membrane comprising: a porous substrate having a contiguous coating of a plasma polymerizate comprising a polysiloxane deposited thereon from a gas plasma comprising a fully alkylated disiloxane and added oxygen, wherein the plasma polymerizate has been deposited at a rate that is increased due to presence of the added oxygen in the gaseous blend, thereby generating a permselective composite membrane.

Claim 15

A membrane comprising: a porous substrate having a contiguous coating of a plasma polymerizate comprising a polysiloxane deposited thereon from a gas plasma comprising a fully alkylated disiloxane and added oxygen, wherein the plasma polymerizate has been deposited at a rate that is increased due to presence of the added oxygen in the gaseous blend, thereby generating a permselective composite membrane.

Claim 16

The membrane according to claim 12 wherein the fully alkylated disiloxane has a formula R 1 R 2 R 3 Si--O--SiR 1 R 2 R 3 where R 1 , R 2 , and R 3 are individually either methyl or ethyl groups.

Claim 17

The membrane according to claim 13 wherein R 1 , R 2 , and R 3 are methyl groups.

Claim 18

The membrane according to claim 12 wherein the polysiloxane polymerizate coating has an oxygen permeability of at least about 1.5×10 -4 cm 3 /cm 2 -sec-cmHg and an oxygen/nitrogen selectivity ratio of greater than 2.3.

Claim 19

The membrane according to claim 15 wherein the porous substrate is a hollow fiber.

Claim 20

The membrane according to claim 16 wherein the hollow fiber consists essentially of polypropylene.

Claim 21

The membrane according to claim 12 wherein the porous substrate has pore sizes in the range of at least about 10 angstroms to at most about 6000 angstroms.

Claim 22

A module for separating gaseous mixtures comprising: a shell means having spaced end portions and defining an elongated chamber therebetween, a plurality of permselective composite hollow fiber membranes having an oxygen permeability of at least about 1.5×10 -4 cm 3 /cm 2 -sec-cmHg and an oxygen/nitrogen selectivity ratio of greater than 2.3, the membranes comprising a porous hollow fiber substrate having a plasma polymerizate comprising a polysiloxane deposited on a surface thereof, the plasma polymerizate being deposited from a gas plasma formed by glow discharge through a gaseous blend comprising a fully alkylated disiloxane and added oxygen, the plasma polymerizate having been deposited at a rate that is increased due to presence of the added oxygen in the gaseous blend, wherein the membranes extend in a substantially parallel relationship within the elongated chamber, the membranes defining an intracapillary space within the hollow fibers and an extracapillary space outside the hollow fibers, fluid communication between the intracapillary and extracapillary spaces being only by means of permeation through the polysiloxane polymerizate coating, means for communicating a gaseous fluid with the extracapillary space, and means for removing a gaseous permeate from the intracapillary space.

Claim 23

A module for separating gaseous mixtures comprising: a shell means having spaced end portions and defining an elongated chamber therebetween, a plurality of permselective composite hollow fiber membranes having an oxygen permeability of at least about 1.5×10 -4 cm 3 /cm 2 -sec-cmHg and an oxygen/nitrogen selectivity ratio of greater than 2.3, the membranes comprising a porous hollow fiber substrate having a plasma polymerizate comprising a polysiloxane deposited on a surface thereof, the plasma polymerizate being deposited from a gas plasma formed by glow discharge through a gaseous blend comprising a fully alkylated disiloxane and added oxygen, the plasma polymerizate having been deposited at a rate that is increased due to presence of the added oxygen in the gaseous blend, wherein the membranes extend in a substantially parallel relationship within the elongated chamber, the membranes defining an intracapillary space within the hollow fibers and an extracapillary space outside the hollow fibers, fluid communication between the intracapillary and extracapillary spaces being only by means of permeation through the polysiloxane polymerizate coating, means for communicating a gaseous fluid with the extracapillary space, and means for removing a gaseous permeate from the intracapillary space.

Claim 24

The module according to claim 19 wherein the porous hollow fiber substrate has pore sizes in the range of at least about 10 angstroms to at most about 6000 angstroms.

Claim 25

The module according to claim 20 wherein the porous hollow fiber substrate consists essentially of polypropylene.

Claim 26

The module according to claim 21 wherein the fully alkylated disiloxane is hexamethyl disiloxane.

Claim 27

An article comprising a substrate having at least one surface, the surface being coated with a plasma polymerizate comprising a polysiloxane, the plasma polymerizate being deposited on the surface from a gas plasma formed from a gaseous blend comprising a vapor of a fully alkylated disiloxane and oxygen, the disiloxane vapor being present in the gaseous blend at a partial pressure of at least about 0.01 Torr to at least about 1.5 Torr, the oxygen being present at a partial pressure ratio of at least about 0.1 to at least about 2.0 relative to the disiloxane vapor, the plasma polymerizate being deposited at an increased rate due to presence of the oxygen in the gaseous blend.

Claim 28

An article comprising a substrate having at least one surface, the surface being coated with a plasma polymerizate comprising a polysiloxane, the plasma polymerizate being deposited on the surface from a gas plasma formed from a gaseous blend comprising a vapor of a fully alkylated disiloxane and oxygen, the disiloxane vapor being present in the gaseous blend at a partial pressure of at least about 0.01 Torr to at least about 1.5 Torr, the oxygen being present at a partial pressure ratio of at least about 0.1 to at least about 2.0 relative to the disiloxane vapor, the plasma polymerizate being deposited at an increased rate due to presence of the oxygen in the gaseous blend.

Claim 29

The article according to claim 23 wherein the plasma polymerizate is deposited at a rate that is increased by at least about 29 percent to at least about 240 percent due to presence of the oxygen in the gaseous blend.

Claim 30

The article according to claim 23 wherein the plasma polymerizate is deposited at a rate of at least about 486 to at least about 2484 angstroms per minute.

Claim 31

The article according to claim 24 wherein the plasma polymerizate is deposited at a rate of at least about 486 to at least about 2484 angstroms per minute.