Polymer systems suitable for blood-contacting surfaces of a biomedical device, and methods for forming

• US 4,861,830 A
• Filed: 06/22/1987
• Issued: 08/29/1989
• Est. Priority Date: 02/29/1980
• Status: Expired due to Term

• Current Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Original Assignee: Th. Goldschmidt AG (Rag-Stiftung)
• Inventors: Ward, Robert S. Jr.
• Primary Examiner(s): Briggs, Sr., Wilbert J.
• Application Number:
  US07/065,416
• Time in Patent Office: 799 Days
• Field of Search: 525/458, 525/453, 525/464, 525/474, 525/92, 525/403, 525/424, 525/431, 525/440, 523/112, 523/113
• US Class Current: 525/92.00A
• CPC Class Codes: A61L 33/062 Mixtures of macromolecular compounds
• CPC Class Codes: A61L 33/068 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds A61L33/062 takes precedence
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/61 Polysiloxanes
• CPC Class Codes: C08G 77/455 containing polyamide, polyesteramide or polyimide sequences
• CPC Class Codes: C08G 77/458 containing polyurethane sequences
• CPC Class Codes: C08G 77/46 containing polyether sequences
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/12 containing polyether sequences

Abstract

A polymer admixture is formed from a base polymer and thermoplastic copolymer additive including polar hard segments and polar and nonpolar soft blocks in graft or block copolymer form. The polymer admixture is characterized by increased contact angle hysteresis and is formed into blood and tissue-contacting surfaces of a biomedical device or into textiles. A preferred additive comprises a segmented block copolymer having polydialkylsiloxanes as nonpolar soft blocks, and a polyurethane as hard segments and a polyalkylene oxide as a polar soft block.

Claims

1. In a method of forming a thermoplastic modified solid polymer the steps of thoroughly blending a minor portion of a thermoplastic polymer additive throughout a major portion of base polymer, whole said polymer additive and base are in fluid form, to form a polymer admixture, said additive comprising an essentially linear first segmented copolymer chain;

said additive characterized by a γ

_c less than said base polymer and said segmented copolymer characterized by the presence of at least one polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature or crystalline melting temperature below 37°

C. with the proviso that said base polymer is not a polycarbonate of 4,4'"'"'-diphenyldimethylmethane.

2. A method according to claim 1 wherein said additive further comprises a second essentially linear polymer chains chemically bonded to said segmented copolymer chain said second polymer chain being selected from a polar homopolymer or a second segmented polymer, said second segmented copolymer characterized by the presence of at least one polar block segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a polar soft block having a glass transition temperature or crystalline melting temperature below 37°

C. and solidifying said polymer admixture.

3. The method of claim 2 wherein said nonpolar soft block is characterized by a γ

_c less than 30 dyne/cm. and a tendency to exude, and said polar hard segments lower, said tendency to exude.

6. The method of claim 1, 2, 4 or 5 in which the base polymer is selected from the group consisting of a polyurethane, polyester-polyether, polyester, polyether-polyamide, polyamide, styrene-isoprene, styrene-butadiene, thermoplastic polyolefin, styrene-saturated olefin, polyester-polyester, ethylenevinyl acetate, ethylene-ethylacrylate, ionomers, or thermoplastic polydiene.

7. The method of claim 2 or 5 in which said polar soft blocks are independently selected from the group consisting of polyalkylene oxide-copolyalkylene oxides, polyvinylalkanoates and polyalkylene oxides, and said nonpolar soft blocks are selected from the group consisting of polydialkylsiloxanes, polyfluoroalkyl alkylsiloxanes, polyolefins, polydienes and polyfluorocarbons.

8. The method of claim 1, 2, 4 or 5 in which said nonpolar soft block is poly(dimethylsiloxane).

9. The method of claim 1, 2, 4, or 5 in which said segmented copolymer chain comprises a nonpolar soft block of a polydialkylsiloxane, and a polar hard segment of a polyurethane.

10. The method of claim 6 in which said base polymer is a segmented polyurethane.

11. The method of claim 10 in which said base polymer is a reaction product of polymeric ether glycols, a diisocyanate, and a difunctional chain extending agent with active groups selected from the group consisting of amines, hydroxy, and mixtures thereof.

12. The method of claim 1 or 5 in which said base polymer and said polar hard segments of said first and second claims are formed of the same type of homopolymer.

13. The method of claim 1, 2, 4 or 5 further comprising the step of annealing said polymer admixture.

14. The method of claim 1, 2, 4 or 5 in which less than about 2 volume % polymer additive is added to said base polymer based on the total polymer admixture.

15. The method of claim 2 or 5 in which said polymer additive comprises at least about 20 volume % of said homopolymer.

16. The method of claim 2 or 5 in which said polymer additive comprises about 20 to 80 volume % of said polar and nonpolar soft blocks.

17. The method of claim 1, 2, 4 or 5 in which said polymer additive comprises about 80 to 20 volume % of said polar hard segments.

18. The method according to claim 6 wherein said base polymer is a thermoplastic polyolefin admixed with plasticizers.

19. The method according to claim 6 wherein said base polymer is polyvinyl chloride.

20. The method of claim 1, 2, 4 or 5 in which said polymer admixture is deposited as a film onto a biomedical device or component thereof.

21. The method of claim 1, 2, 4 or 5 in which said additive and base polymer are in molten form during dispersion and solidify on cooling.

22. The method of claim 1, 2, 4 or 5 in which said polymer admixture is dissolved in solvent during mixing and said solvent is removed to solidify said polymer mixture.

23. The method of claim 1, 2, 4 or 5 in which said base polymer comprises a curable thermosetting fluid polymer which is solidified by curing.

24. The method of claim 1, 2, 4 or 5 in which said modified solid polymer is formed into an exposed blood and tissue-contacting surface of a biomedical device, or component thereof.

25. The method according to claim 24 wherein said surface comprises fibers.

27. The method of claim 1, 2, 4 or 5 in which no greater than about 5 volume % of said polymer additive is dispersed in at least 95% of said base polymer.

4. In a method of forming a thermoplastic modified solid polymer the steps of thoroughly blending a minor portion of a thermoplastic polymer additive throughout a major portion of a base polymer, while said polymer additive and base polymer are in fluid form, to form a polymer admixture, said additive comprising an essentially linear first segmented copolymer chain;

said additive characterized by a γ

_c less than said base polymer and said segmented copolymer characterized by the presence of at least one polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature or crystalline melting temperature below 37°

C., wherein said soft blocks control the surface properties of said modified solid polymer, with the proviso that said base polymer is not a polycarbonate of 4,4'"'"'-diphenyldimethyl- methane.

5. A method according to claim 4 wherein said additive further comprises a second essentially linear polymer chains chemically bonded to said segmented copolymer chain said second polymer chain being selected from a polar homopolymer or a second segmented polymer, said second segmented copolymer characterized by the presence of at least one polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a polar soft block having a glass transition temperature or crystalline melting temperature below 37°

C. and solidifying said polymer admixture.

26. The method according 1, 2, 4 or 5 wherein said modified solid polymer is formed into a textile or component of the same.

28. In a method of forming a polymer admixture, the steps of

(a) thoroughly dispersing no greater than about 5 volume % of a copolymer additive throughout at least 95 volume % of a base polymer, while said copolymer additive and base polymer are in fluid form, to form a polymer admixture, said copolymer additive comprising a nonpolar soft poly (dialkysiloxane) segment component chemically bonded to a polar hard polyurethane segment, said copolymer additive being characterized by a γ

_c less than said base polymer admixture being characterized by a γ

_c between about 10 and 35 dyne/cm., and

(b) solidifying said polymer admixture.

29. A biomedical device or component of the same, including a blood-compatible, blood-contacting surface formed of a polymer admixture comprising at least 95 volume % of a base polymer and no greater than 5 volume % of a polymer additive comprising a first homopolymer component chemically bonded to at least a second homopolymer component of a different type than said first component, said polymer additive being dispersed throughout said base polymer and being characterized by a γ

_c less than said base polymer, said polymer admixture being characterized by a γ

_c between about 10 and 35 dyne/cm.

30. The biomedical device of claim 29 in which said first component is characterized by a γ

_c less than 30 dyne/cm. and a tendency to exude, and said second component lowers said tendency to exude.

31. The biomedical device of claim 29 in which said first component is a homopolymer selected from the group consisting of polydialkylsiloxanes, polyfluoroalkyl alkylsiloxanes, polyalkylene oxides, polyolefins, polydienes and polyfluorocarbons.

32. The biomedical device of claim 29 in which said first component is poly(dimethylsiloxane).

33. The biomedical device of claim 29 in which said first component is a polydialkylsiloxane and said second component is a polyurethane.

34. The biomedical device of claim 29 characterized by blood compatibility in the form of a blood contact device or component thereof.

35. The biomedical device of claim 29 characterized by blood compatibility in the form of a blood contact layer adhered to the surface of a blood contact device.

36. The biomedical device of claim 29 in which a portion of said polymer additive is in the form of a continuous layer on the surface of a blood contact device.

37. The biomedical device of claim 29 in which a portion of said polymer additive comprises a linear multiblock copolymer with blocks of at least said first and second component on the surface of a blood contact device.

38. The biomedical device of claim 29 in which a portion of said polymer additive comprises a graft copolymer with a substrate formed of said first component and pendant chains formed of said second component on the surface of a blood contact device.

39. The biomedical device of claim 29 in which a portion of said polymer additive comprises a graft copolymer with a substrate formed of said second component and pendant chains formed of said first component on the surface of a blood contact device.

40. A modified solid polymer blend formed of a base polymer and a solid thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising a first essentially linear segmented copolymer chain and a second essentially linear polymer chain chemically bonded to said segmented copolymer chain, said second polymer chain comprising a polar homopolymer;

said additive characterized by γ

_c less than said base polymer and said first segmented copolymer chain characterized by the presence of at least one polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature or crystalline melting temperature below 37°

C.;

said polar homopolymer characterized by the presence of at least one second polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., said polar hard segments independently selected from the group consisting of a polyurethane and polycarbonate of 4,4'"'"'-diphenylmethylmethane, wherein said nonpolar and polar soft blocks control the surface properties of said modified solid polymer blend.

41. A modified, solid polymer and a solid thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising an essentially linear segmented copolymer chain;

said additive characterized by γ

_c less than said base polymer and said segmented copolymer chain characterized by the presence of at least one polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature below 37°

C. said additive further comprising a second essentially linear polymer chain chemically bonded to said segmented copolymer chain, said second polymer chain selected from a polar homopolymer or a second segmented copolymer, said second segmented copolymer or polar homopolymer characterized by the presence of at least one second polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., said polar hard segments independently selected from the group consisting of a polyurethane and a polyurethaneurea, and said second segmented copolymer further characterized by the presence of a polar soft block having a glass transition temperature or crystalline melting temperature below 37°

C. with the proviso that said base polymer is not a polycarbonate of 4,4'"'"'-diphenyldimethylmethane; and

wherein said base polymer and said polar hard segments are formed of the same type of homopolymer.

42. A method of forming an exposed blood-contacting surface of biomedical device or component thereof of low surface free energy and increased contact angle hysteresis comprising the steps of

(a) reacting up to about 2 volume % of a reactive polysiloxane oligomer with at least 98 volume % of a base polymer, while said oligomer and base polymer are in fluid from to form a fluid polymer admixture of at least 95 volume % pure base polymer and no greater than 5 volume % of a copolymer of said base polymer and said oligomer, and

(b) solidifying said polymer admixture, said copolymer comprising an essentially linear segmented copolymer chain;

said copolymer characterized by a γ

_c less than said base polymer and said segmented chain characterized by the presence of at least one polar hard polyurethane or polyurethaneurea segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar polysiloxane soft block having a glass transition temperature or crystalline melting temperature below 37°

C. with the proviso that said base polymer is not a polycarbonate of 4,4'"'"'-di-phenyldimethylmethane and said polymer admixture being characterized by a γ

_c between about 10 and 35 dyne/cm.

43. The method according to claim 42 wherein said surface comprises fibers.

44. The method of claim 42 in which said polymer admixture is formed into a textile or component thereof.

45. In method of forming the exposed blood-contacting surface of a biomedical device, or components thereof, the steps of

(a) thoroughly dispersing no greater than about 5 volume % of a polymer additive throughout at least 95 volume % of a base polymer, while said polymer additive and base polymer are in fluid form, to form a polymer admixture, said polymer additive comprising a thermoplastic segmented block copolymer characterized by the presence of at least one polar hard segment of from 1 to 10 repeating monomer units, said segment selected from the group consisting of a polyurethane and a polyurethaneurea and having a glass transition temperature or crystalline melting temperature above 37°

C. and a nonpolar soft block having a glass transition temperature or a crystalline melting temperature below 37°

C., said polymer additive being characterized by a γ

_c between about 10 and 35 dyne/cm; and

(b) solidifying said polymer mixture and

(c) depositing said polymer mixture as a film onto a biomedical device or component thereof.

46. The method of claim 45 which said additive and base polymer are in molten form during dispersion and solidify on cooling.

47. The method of claim 45 in which said polymer admixture is dissolved in solvent during mixing and said solvent is removed to solidify said polymer admixture.

48. The method of claim 45 said base polymer comprises a curable thermosetting fluid polymer which is solidified by curing.

49. A polymeric blood-contacting surface of a biomedical device or component thereof comprising at least 95 volume % of a base polymer and no greater than 5 volume % of a solid polymer additive comprising a poly(dialkysiloxane) block chemically bonded to a polyurethane segment of from 1 to 10 repeating monomer units said polymer additive being dispersed throughout said base polymer and being characterized by a γ

_c less than said base polymer, said polymer admixture being characterized by a γ

_c between about 10 and 35 dyne/cm.

50. A modified solid polymer blend formed of a base polymer including end groups capable of hydrogen bonding or reacting with proteins and a solid thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising a first essentially linear segmented copolymer chain and a second essentially linear polymer chain chemically bonded to said first segmented copolymer chain, said second polymer chain being selected from a polar homopolymer or a second segmented copolymer

said additive characterized by a γ

_c less than said base polymer and said first segmented copolymer chain characterized by the presence of at least one polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature or crystalline melting temperature below 37°

C.;

said second segmented copolymer or polar homopolymer characterized by the presence of at least one second polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and said second segmented copolymer further characterized by the presence of a polar soft block having a glass transition temperature or crystalline melting temperatures below 37°

C., said polar hard segments independently selected from the group consisting of a polyurethane and a polyurethaneura wherein said nonpolar and polar soft blocks control the surface properties of said modified solid polymer blend; and

said base is selected from the group consisting of a polyurethane, polyester, polyesterether, polyamide, polyether-polyamide, styrene-isoprene, styrene-butadiene, thermoplastic polyolefin, styrene-saturated olefin, polyester-polyester, ethylenevinyl acetate, ethylene-ethylacrylate, ionomers and thermoplastic polydiene.

51. A modified, solid polymer formed of a base polymer including end groups capable of hydrogen bonding or reacting with proteins and a solid thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising an essentially linear segmented copolymer chain;

said additive characterized by γ

_c less than said base polymer and said segmented copolymer chain characterized by the presence of at least one polar hard segment having a glass transition temperature of crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature below 37°

C. said additive further comprising a second essentially linear polymer chain chemically bonded to said segmented copolymer chain, said second polymer chain being selected from a polar homopolymer or a second segmented copolymer, said second segmented copolymer or polar homopolymer characterized by the presence of at least one second polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., said polar hard segments independently selected from the group consisting of a polyurethane and a polyurethaneurea, and said second segmented copolymer further characterized by the presence of polar soft block having a glass transition temperature or crystalline melting temperature below 37°

C.; and

said base polymer is selected from the group consisting of a polyurethane, polyester, polyester-polyether, polyamide, polyether-polyamide, styrene-isoprene, styrene-butadiene, thermoplastic polyolefin, styrene-saturated olefin, polyester-polyester, ethylene-vinyl acetate, ethylethylacrylate, ionomers, and thermoplastic polydiene.

52. A modified solid polymer blend formed of a base polymer comprising a segmented block polymer and a solid thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising a first essentially linear segmented copolymer chain and a second essentially linear polymer chain chemically bonded to said first segmented copolymer chain, said second polymer chain being selected from a polar homopolymer or a second segmented copolymer

said additive characterized by a γ

_c less than said base polymer and said first segmented copolymer chain characterized by the presence of at least one polar hard segment having a glass transition temperatures or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature or crystalline melting temperature below 37°

C.;

said second segmented copolymer or polar homopolymer characterized by the presence of at least one second polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and second segmented copolymer further characterized by the presence of a polar soft block having a glass transition temperature or crystalline melting temperature below 37°

C., said polar hard segments independently selected from the group of a polyurethane and a polyurethaneurea wherein said nonpolar and polar soft blocks control the surface properties of said modified solid polymer blend; and

said base polymer is selected from the group consisting of a polyurethane, polyester, polyester-polyether, polyamide, polyether-polyamide, styrene-isoprene, styrene-butadiene, thermoplastic polyolefin, styrene-saturated olefin, polyester-polyester, ethylenevinyl acetate, ethylene-ethylacrylate, ionomers and thermoplastic polydiene.

53. A modified, solid polymer formed of a base polymer comprising a segmented block copolymer and a solid thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising an essentially linear segmented copolymer chain;

said additive characterized by a γ

_c less than said base polymer and said segmented copolymer chain characterized by the presence of at least one polar hard segment having a transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature below 37°

C. said additive chemically bonded to said segmented copolymer chain, said second polymer chain being selected from a polar homopolymer or a second segmented copolymer, said second segmented copolymer or polar homopolymer characterized by the presence of at least one second polar hard segment having a glass transition temperature or crystalline melting temperature 37°

C., said polar hard segments independently selected from the group consisting of a polyurethane and a polyurethaneurea, and said second segmented copolymer further characterized by the presence of a polar soft block having a glass transition temperature or crystalline melting temperature below 37°

C.; and

said base polymer is selected from the group consisting of a polyurethane, polyester, polyester-polyether, polyamide, polyether-polyamide, styrene-isoprene, styrene-butadiene, thermoplastic polyolefin, styrene, saturated olefin, polyester-polyster, ethylene-vinyl acetate, ethylethylacrylate, ionomers, and thermoplastic polydiene.

54. A modified solid polymer blend formed of a segmented polyurethane base polymer and a solid thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising a first essentially linear segmented copolymer chain and a second essentially linear polymer chain chemically bonded to said first segmented copolymer chain, said second polymer chain being selected from a polar homopolymer or a second segmented copolymer

said additive characterized by a γ

_c less than base polymer and said first segmented copolymer chain characterized by the presence of at least one polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature or crystalline melting temperature below 37°

C.;

said second segmented copolymer or polar homopolymer characterized by the presence of at least one second polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and said second segmented copolymer further characterized by the presence of a polar soft block having a glass transition temperature or crystalline melting temperature below 37°

C., said polar hard segments independently selected from the group consisting of a polyurethane and a polyurethaneurea with the proviso that said base polymer is not a polycarbonate of 4,4'"'"'-diphenylmethylmethane, wherein said nonpolar and polar soft blocks control the surface properties of said modified solid polymer blend.

55. A modified solid polymer according to claim 54 wherein said segmented polyurethane is a reaction product of polymeric ether glycols, a diisocyanate, and a disfunctional chain extending agent with active groups selected from the group consisting of amines, hydroxy, and mixtures thereof.

56. A modified, solid polymer formed of a segmented polyurethane base polymer and a solid thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising an essentially linear segmented copolymer chain;

said additive characterized by a γ

_c less than said base polymer and said segmented copolymer chain characterized by the presence of at least one polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature below 37°

C. said additive further comprising a second essentially linear polymer chain chemically bonded to said segmented from a polar homopolymer or a second segmented copolymer, said second segmented copolymer or polar homopolymer characterized by the presence of at least one second polar hard segment having a glass transition temperature or crystalline melting temperature above 37°

C., polar hard segments independently selected from the group consisting of a polyurethane and a polyurethaneurea, and said second segmented copolymer further characterized by the presence of a polar soft block having a glass transition temperature or crystalline melting temperature below 37°

C. with the proviso that said base polymer is not a polycarbonate of 4,4'"'"'-diphenyldimethylmethane.

57. A modified solid polymer according to claim 56 wherein said segmented polyurethane is a reaction product of polymeric ether glycols, a diisocyanate, and a difunctional chain extending agent with active groups selected from the group consisting of amines, hydroxy, and mixtures thereof.

58. A modified solid polymer formed of a bas polymer formed of a homopolymer and characterized by a glass transition temperature below 140°

C. and a thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising an essentially linear segmented copolymer chain;

said additive characterized by γ

_c less than said base polymer and said segmented copolymer chain characterized by the presence of at least one polar hard segment formed of said same homopolymer comprising said base polymer and having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature or crystalline melting temperature below 37°

C. with the proviso that said base polymer is not a polycarbonate of 4,4'"'"'-diphenyldimethylmethane.

59. A modified solid formed of a base formed of a homopolymer, and a thermoplastic segmented block copolymer additive blended with said base polymer said modified solid polymer characterized by a relative contact angle hysteresis greater than that of said base polymer,

said additive comprising an essentially linear segmented copolymer chain;

said additive characterized by a γ

_c less than said base polymer and said segmented copolymer chain characterized by the presence of at least one polar hard segment formed of said same homopolymer comprising said base polymer and having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature or crystalline melting temperature below 37°

C. with the proviso that said base polymer is not a polycarbonate of 4,4'"'"'-diphenyldimethylmethane.

60. A modified solid polymer formed of a base polymer formed of a homopolymer, and a thermoplastic segmented block copolymer additive blended with said base polymer,

said additive comprising an essentially linear segmented copolymer chain;

said additive characterized by a γ

_c less than said base polymer and said segmented copolymer chain characterized by the presence of at least one polar hard segment formed of said same homopolymer comprising said base polymer and having a glass transition temperature or crystalline melting temperature above 37°

C., and a nonpolar soft block having a glass transition temperature or crystalline melting temperature below 37°

C. with the proviso that said base polymer is not a polycarbonate of 4,4'"'"'-diphenyldimethylmethane;

wherein said soft blocks control the surface properties of said modified solid polymer.

61. A blood-contacting surface of a biomedical device or component of said device comprising a polymer admixture of low surface free energy, said admixture formed by

(a) reacting about 0.0002 to 2 volume % of a homopolymer additive with at least 98 volume % of a base polymer, while said homopolymer additive and base polymer are in fluid form to form a fluid polymer admixture of at least 95 volume % pure base polymer and no greater than 5 volume % of a copolymer of said base polymer and said homopolymer additive, and

solidifying said polymer admixture, said additive polymer being characterized by a γ

_c less than said base polymer and said polymer admixture being characterized by a γ

_c between about 10 and 35 dyne/cm.