SUBSTRATE SURFACE MODIFICATION UTILIZING A DENSIFIED FLUID AND A SURFACE MODIFIER

1 . A method of modifying the surface properties of a polymeric substrate, comprising:

providing a densified fluid having at least one silicone and/or fluorine-containing compound dispersed or dissolved therein;

providing a polymeric substrate having a surface capable of incorporating the at least one silicone and/or fluorine-containing compound in a manner that enhances one or more surface properties of the polymeric substrate;

positioning the polymeric substrate in a reactor;

introducing into the reactor the densified fluid having the at least one silicone and/or fluorine-containing compound dispersed or dissolved therein; and

maintaining the reactor under conditions such that the compound transfers from

the densified fluid into the surface of the polymeric substrate.

2 . The method of claim 1 , wherein the densified fluid is introduced into the reactor under subcritical conditions.

3 . The method of claim 1 , wherein the densified fluid is introduced into the reactor under supercritical conditions.

4 . The method of claim 2 , wherein the subcritical conditions are maintained in the reactor for a controlled period of time, whereupon the conditions in the reactor are adjusted to supercritical conditions.

5 . The method of claim 1 , wherein the densified fluid comprises densified carbon dioxide.

6 . The method of claim 1 , wherein the silicone and/or fluorine-containing compound includes a polar functional group.

7 . The method of claim 6 , wherein the functional group comprises a polar group.

8 . The method of claim 6 , wherein the functional group is selected from the group consisting of hydroxyl, amino, carboxylic acid, nitro, thio, urea, and urethane.

9 . The method of claim 1 , wherein the densified fluid comprises densified carbon dioxide.

10 . The method of claim 1 , wherein the polymeric substrate is catheter tubing.

11 . The method of claim 1 , which is effective to lower the surface tension of a surface of the polymeric substrate.

12 . (canceled)

13 . A method for modifying the surface properties of catheter tubing, comprising:

treating the catheter tubing with a densified fluid having a surface modifying agent dispersed or dissolved therein, so as to impregnate the catheter tubing with the surface modifying agent and thereby reduce the surface tension of an external surface of the catheter tubing.

14 . The method of claim 13 wherein the densified fluid comprises densified CO2.

15 . The method of claim 14 wherein the densified fluid comprises supercritical CO 2 .

16 . The method of claim 13 wherein the catheter tubing is comprised of an elastomeric polymer.

17 . The method of claim 16 wherein the catheter tubing is comprised of a polyurethane elastomer or a nylon elastomer.

18 . The method of claim 13 wherein said treating is effective to increase the lubricity of the external surface of the catheter tubing.

19 . The method of claim 13 wherein said treating is effective to reduce the thrombogenicity of the external surface of the catheter tubing.

20 . The method of claim 13 wherein the surface modifying agent is a silicone-containing or fluorine-containing compound.

21 . The method of claim 20 wherein the surface modifying agent is a silicone oil.

22 . The method of claim 21 wherein the surface modifying agent is a hydroxyl functional silicone oil.

23 . The method of claim 20 wherein the surface modifying agent is a compound having the formula

—(CF 2 ) n —R;

—(O—CF 2 —CF 2 ) n —R; or

—{CF(CF 3 )—CF 2 ) n ,—R;

wherein: n is equal to 1 to about 100, and

R is —OH;

—NH 2 ;

—COOH

—COOCH 3 ; or

—OCOC(CH 3 )═CH 2 .

24 . The method of claim 20 wherein the surface modifying agent is a compound having the formula

—{Si(CH 3 ) 2 —O} n —Si(CH 3 ) 2 —R 1

wherein: n=1 to about 100, and

R 1 is —OH;

—NH 2 ;

—COOH;

—(CH 2 CH 2 O) m H, where m=1 to about 20;

—OCOC(CH 3 )=CH 2 ; or

—(CH 2 ) p O(CH 2 ) q OH, where p and q each=1 to about 6, and can be the same as or different from each other.

25 . The method of claim wherein the surface modifying agent is a compound having the formula

HOCH 2 CH 2 OCH 2 CH 2 CH 2 —Si(CH 3 ) 2 —O—{Si(CH 3 ) 2 —O} n —Si(C H 3 ) 2 —R 2

wherein —R 2 is a C 1 to C 10 alkyl group.

26 . A medical device, comprising a polymeric substrate having a silicon-containing or fluorine-containing surface modifying agent dispersed in the polymeric substrate and effective to reduce the surface tension of a surface of the substrate.

27 . The medical device of claim 26 , which is a catheter, and wherein the polymeric substrate is tubing of the catheter.

28 . The medical device of claim 26 , wherein the polymeric substrate is comprised of an elastomeric polymer.

29 . The medical device of claim 28 , wherein the elastomeric polymer is comprised of a polyurethane elastomer or a nylon elastomer.

30 . (canceled)

31 . The medical device of claim 26 wherein the surface modifying agent is a silicone oil.

32 . The medical device of claim 31 wherein the surface modifying agent is a hydroxyl functional silicone oil.

33 . The medical device of claim 26 wherein the surface modifying agent is a compound having the formula

—(CF 2 ) n —R;

(O—CF 2 —CF 2 ) n —R; or

—{CF(CF 3 )—C F 2 } n —R;

wherein: n is equal to 1 to about 100, and

R is —OH;

—NH 2 ;

—COOH;

—COOCH 3 ; or

—OCOC(CH 3 )=CH 2 .

34 . The medical device of claim wherein the surface modifying agent is a compound having the formula

—{Si(CH 3 ) 2 —O} n —Si i (CH 3 ) 2 —R 1

wherein: n=1 to about 100, and

R 1 is —OH;

—NH2;

—COOH;

—(CH 2 CH 2 O) m H, where m=1 to about 20;

—OCOC(CH 3 )═CH 2 ; or

—(CH 2 ) p O(CH 2 ) q OH, where p and q each=1 to about 6, and can be the same as or different from each other.

35 . The medical device of claim 26 wherein the surface modifying agent is a compound having the formula

HOCH 2 CH 2 OCH 2 CH 2 CH 2 —Si(CH 3 ) 2 —O—{Si(CH 3 ) 2 —O} n —Si(CH 3 ) 2 —R 2

wherein —R is a C 1 to C 10 alkyl group.