Stock material or miscellaneous articles – Composite – Of metal
Patent
1991-03-25
1992-10-06
Beck, Shrive
Stock material or miscellaneous articles
Composite
Of metal
428517, 428458, 428520, 427488, B32B 2708, B32B 1508, B05D 306
Patent
active
051530724
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to methods of controlling the chemical structure of thin films formed by plasma deposition, and to films produced by these methods.
BACKGROUND OF THE INVENTION
Plasma deposition of thin organic films has increased in importance in a number of areas of technology in recent years. Overlayer films on solid substrates can be produced without exposing the solids to solvents or high energy radiation. Films deposited by this method show many desirable characteristics including ease of preparation, uniformity, conformal coverage of complex substrates, excellent adhesion to a variety of substrates and the ability to generate unique chemistries. In addition, the overlayer films do not penetrate significantly into the substrate and, therefore, do not affect the mechanical properties of the substrate. These films are typically free of leachable components and can be designed to prevent leachable components in the substrate from diffusing out.
The primary disadvantage of plasma deposited films is that they are of illdefined chemistry. Because of the complexity of the composition of the plasma phase and the many possible reaction mechanisms that may lead to the incorporation of a particular atom or functional group into the growing film, the final film obtained from these types of depositions is hard to predict or control. Participating reactions have been grouped into plasma phase and surface reactions, and generalized mechanistic schemes for these reactions have been developed. H. Yasuda, J. Polym. Sci. Macromol. Rev., 16, 199-14 293 (1981). During a plasma deposition, an organic compound (precursor), which may or may not be polymerizable by traditional methods, is dissociated and rearranged to produce a new structure and finally deposited onto a substrate in a chemical environment that is typically quite different from the original. For example, if an organic amine is introduced into the plasma environment with the intent of introducing amine fuctionalities on the film surface, a wide range of nitrogen containing organic functional groups will actually be obtained. Consequently, chemical tailoring of films by this method has often been quite laborious and typically phenomenological in approach.
Bell and coworkers were among the first groups to study the effects of deposition variables on film chemistry. K. Nakajima, A. T. Bell, and M. Shen, J. Apl. Polym. Sci., 23,2627-2637 (1979). They produced films under conditions where the dominant functional group is --CF.sub.2 --. They noted that these conditions also favored low deposition rates, and that at conditions which produce higher deposition rates, the number of --CF.sub.2 -- groups decreases and a more crosslinked polymer is formed. However, they did not disclose or suggest that a temperature differential between substrate and deposition chamber could be employed to control chemistry of the deposited film.
The dependence of film chemistry on operational variables has thus far been mainly expressed in terms of the degree of precursor fragmentation that occurs between the time of exposure to the plasma and the incorporation into the film matrix. Thus, if a functional group of interest is to be incorporated into a film without fragmentation or rearrangement, the operational parameters of the deposition must be identified which affect fragmentation and these must be tailored to prevent extensive fragmentation.
Clark and coworkers also studied the effects of deposition variables on film chemistry. D. T. Clark, Pure & Appl. Chem., 54, 415-438 (1982);D. T. Clark and M. Z. Abrahman, J. Polym. Sci., Polym. Chem. Ed., 20, 691-706 (1982); and D. T. Clark and M. Z. Abrahman, J. Polym. Sci., Polym. Chem. Ed., 20 1729-1744 (1982). Using X-ray photoelectron spectroscopy (XPS) analysis of various types of fluorocarbon deposits, they were able to show that the films deposited at low power levels incorporated precursor with a low degree of functional group (e.g., aromatic) fragmentation than at high power levels. They also showed that higher
REFERENCES:
patent: 3475307 (1969-10-01), Knox et al.
patent: 4132829 (1979-01-01), Hudis
patent: 4212719 (1980-07-01), Osada et al.
patent: 4419382 (1983-12-01), Sliemers
patent: 4424311 (1984-01-01), Nagaoka et al.
patent: 4656083 (1987-04-01), Hoffman et al.
patent: 4705612 (1987-11-01), Shimomura et al.
patent: 5002794 (1991-03-01), Ratner et al.
Yasuda et al., "Plasma Polymerization Investigated by the Substrate Temperature Dependence," Journal of Polymer Science: Polymer Chemistry Edition, 23:87-106 (1985).
Sherman, A., "Plasma-Assisted Chemical Vapor Deposition Processes and Their Semiconductor Applications," Thin Solid Films, 113:135-149 (1984).
Munro et al., "The Influence of Power and Substrate Temperature on Chemical Composition, Determined by ESCA, of the Inductively Coupled RF Plasma Polymerization of Acrylonitrile," Journal of Polymer Science: Polymer Chemistry Edition, vol. 23, 479-488 (1985).
Czornyj, G., "The Effect of Temperature on the Morphology of Plasma Polymerized Fluorocarbon Films," ACS Org. Coatings Appl. Polym. Proc., 47:457-461 (1982).
Witt et al., "Convenient Direct Synthesis of (SN).sub.x Films From S.sub.4 N.sub.4 at Lower Temperatures," American Chemical Society, pp. 1668-1669 (1983).
Merrill et al., "Polyether Networks: Fibrinogen Adsorption and Platelet Retention," The 11th Annual Meeting of the Society for Biomaterials, 106 (1985).
Nagoaka et al., "Interaction Between Blood Components and Hydrogels With Poly(oxyethylene) Chains", Polymers as Biomaterials, 8352:361-375 (1984).
Merrill et al., "Polyethylene Oxide as a Biomaterial," American Society for Artificial Internal Organs, 2:60-64 (1983).
Ho Lee et al., "Protein-Resistant Surfaces Prepared by PEO-Containing Block Copolymer Surfactants," Journal of Biomedical Materials Research, 23:351-368 (1989).
Nojiri et al., "In vivo Protein Adsorption Onto Polymers: A Transmission Electron Microscopic Study," Trans. Am. Soc. Artif. Intern. Organs, XXV:357-361 (1989).
Maechling-Strasser et al., "Synthesis and Adsorption of a Poly(N-Acetylethyleneimine)-Polyethyleneoxide-Poly(N-Acetylethyleneimine) Triblock-Copolymer at a Silica/Solution Interface. Influence of Its Preadsorption on Platelet Adhesion and Fibrinogen Adsorption," Journal of Biomedical Materials Research, 23:1395-1410 (1989).
Andrade et al., "Surfaces and Blood Compatibility Current Hypotheses," Trans. Am. Soc. Arif. Intern. Organs, XXXIII:75-84 (1987).
Marmur et al., "Sedimentation and Adhesion of Blood Platelets Under a Centrifugal Force," Journal of Colloid and Interface Science, 104:390-397 (1985).
Nishimura et al., "Adhesion Behavior of Rat Lymphocytes on Poly(g-Benzyl L-Glutamate) Derivatives Having Hydroxyl Groups or Poly(Ethylene Glycol) Chains", Makromol. Chem., 185:2109-2116 (1984).
Akizawa et al., "Efficiency and Biocompatability of a Polyethylene Glycol Grafted Cellulosic membrane During Hemodialysis," Trans. Am. Soc. Artif. Intern. Organs, XXXV:333-335 (1989).
Bots et al., "Small Diameter Blood Vessel Prostheses From Blends of Polyethylene Oxide and Polypropylene Oxide," Biomaterials, 7(5):393-399 (1986).
Lee et al., "Surface Properties of Aqueous Peo-Containing Block Copolyme
This invention was made with government support under grant number 5 R01 HL 19419 awarded by the National Institutes of Health. The government has certain rights in this invention.
Lopez Gabriel P.
Ratner Buddy D.
Beck Shrive
King Roy V.
The Board of Regents of the University of Washington
LandOfFree
Method of controlling the chemical structure of polymeric films does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of controlling the chemical structure of polymeric films , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of controlling the chemical structure of polymeric films will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1188304