Polymeric metal coating

Details Polymeric metal coating Polymeric metal coating

1999-06-09

2001-06-12

Ceperley, Mary E. (Department: 1641)

Chemistry: analytical and immunological testing

Involving an insoluble carrier for immobilizing immunochemicals

Carrier is organic

C106S014130, C106S170460, C435S178000, C435S179000, C436S524000, C436S525000, C436S526000, C436S527000, C436S529000, C436S530000, C530S391100

Reexamination Certificate

active

06245579

ABSTRACT:

DESCRIPTION
The invention relates to polymeric thiosulfates, to a method for their manufacture and to their application to coating surfaces.
Monomeric alkylthiosulfates (R—S—SO
3
) are known as Bunte salts [H. Distler,
Angew. Chem.
1967, 79, pp 520-9]. In general they are prepared by reacting alkylbromides with sodium thiosulfate. Bunte salts are widely applicable. For instance they are used ass insecticides or fungicides, also as radiation protectants and paint additives. Except for polystyrene derivatives [Tabushi et al,
J. Chem. Soc. Japan,
Ind. Chem. Sec., 1964, 67; p 478] no polymeric thiosulfates are known to date in the literature. Nor are any applications of organic thiosulfates known regarding the making of ultrathin films.
The Langmuir-Blodgett technique [F. Embs, D. Funhoff, A. Laschewsky, U. Licht, H. Ohst, W. Prass, H. Ringsdorf, G. Wegner, R. Wehrmann,
Adv. Mater.
1991, 3, pp 25-31] is used to prepare ultrathin films on solid hydrophobic substrates. However this procedure is unusually costly and suitable only for small, planar surfaces. Moreover this procedure is unsuitable for coating complex structures such as hollow bodies. Moreover depositing layers of polyelectrolyte on charged substrates [G. Decher, J. Schmitt, L. Heiliger, H. U. Siegmund, German Patent application P 433,107.6; G. Decher, J-D. Hong,
Makromol. Chem.,
Macromol. Symp. 1991, 46, pp 321-7] is known, however it is restricted solely to coating charged surfaces. Chemical modification of reactive substrates and chemical adsorption of alkylthiols on metal surfaces is also known [L. H. Dubois, R. G. Nuzzo,
Annu. Rev. Phys. Chem.,
1992, 43, pp 437-463; R. G. Nuzzo, F. A. Fusco, D. L. Allara,
J. Am. Chem. Soc.
1987, 109, pp 2358-2368]. The known chemical adsorption of monomeric thiols, for instance alkylthiols, on surfaces of precious and semi-precious metals offers the advantage of being highly selective and that thereby film contamination by impurities can be substantially precluded. Using alkylthiols, it is possible for instance to deposit from solution two-dimensional crystalline monolayers onto gold surfaces. Hydrophobed gold surfaces are thus created. A hydrophilic coating also can be prepared using alkylthiols with hydrophilic end groups, for instance &agr;-&ohgr; hydroxyalkylthiols [R. G. Nuzzo, L. H. Dubois, D. L Allara,
J. Am. Chem. Soc.
1990, 112, pp 558-569]. These described thiols incur the substantial drawback that their water-solubility is low. Accordingly they require using organic solvents in order to be applicable to coating metal surfaces. A further drawback is that the layers produced using known alkylthiols are crystalline. The crystallinity of the coating entails several drawbacks. On one hand crystalline layers form a so-called domain structure. As a result the coating may only coat inadequately at the boundary surfaces of these domains. Another drawback is a risk of phase separation of the monolayers on metal surfaces if mixtures of different alkylthiols are used. Such de-mixing of the crystalline layer significantly degrades both the mechanical and the optical properties of such a coating. Furthermore the known monomeric alkylthiols are unusually smelly and most often are toxic, restricting professional application of such compounds.
Aside the thiols of low molecular weight, thiol derivatives of oligomeric carbohydrates, for instance cyclodextrin thiols, have been made to chemically adsorb [G. Nelles, M. Weisser, R. Back, P. Wohlfart, G. Wenz, S. Mittler-Neher,
J. Am. Chem.Soc.
1996, 118, pp 5039-5046]. In this procedure hydrophilic coatings of thicknesses of few nanometers were prepared. However oligomeric and polymeric thiol derivatives incur the drawback to crosslink in solution while forming S—S bonds. Moreover the synthesis of cyclodextrin thiols described to-date has been very expensive and complex.
The patent document WO 88 5473 furthermore describes coating metal surfaces by chemical adsorption of mono- or poly-functional molecules. However none of the described functional groups is a thiol- or a thiolsulfate group. Instead the functional groups described therein contain halogenalkyl groups or unsaturated groups. Use of organic solvents is recommended for any such application.
Therefore it is the objective of the present invention to prepare novel compounds free of objectionable odors, having low toxicity and being substantially more soluble in aqueous media than the heretofore known compounds, and are intended to be amorphous, hydrophilic and tight coatings on metals and offering high mechanical strength and chemical resistance. Moreover such compounds shall allow coating metal surfaces in substantially more ecological, more economical and simpler manner.
This problem is solved by the implementing means stated in the claims. In particular soluble, polymeric thiosulfates are prepared having the structural units of the general formulas I and/or II
where AK is an anhydro-carbohydrate unit, the residue R
1
is a hydrogen atom, a straight-chain or a branched-chain (C
1
-C
30
) alkyl residue, a straight-chain or a branched-chain (C
2
-C
30
) alkylenoxyalkyl residue, a straight-chain or a branched-chain (C
1
-C
30
) alkanoyl residue, a straight-chain or branched-chain (C
2
-C
30
)alkylenoxoalkyl residue, a (C
2
-C
30
) alkenyl residue, a (C
2
-C
30
) alkenoyl residue, a (C
2
-C
30
) alkinyl residue, a straight-chain or branched-chain (C
5
-C
30
) cylcoalkyl residue, a substituted or unsubstituted (C
5
-C
30
) aryl residue possibly with one or more heteroatoms, or a substituted or unsubstituted (C
5
-C
30
) aryloyl residue possibly having one or several heteroatoms, where the residue R
1
each time is bound to an oxygen atom of the anhydro-carbohydrate unit and the degree of substitution x
3
is 0, 1, 2 or 3, where the residue R
2
is a bivalent spacer selected from a substituted or unsubstituted (C
1
-C
30
) alkylene residue, a substituted or unsubstituted (C
1
-C
30
) hydroxyalkylene residue, a substituted or unsubstituted (C
1
-C
30
) oxoalkylene residue, a substituted or unsubstituted (C
2
-C
30
) alkylenoxoalkylene residue, a substituted or unsubstituted (C
2
-C
30
) alkyleneoxyalkylene residue, a substituted or unsubstituted (C
2
-C
30
) hydroxyalkylenoxyalkylene residue, a substituted or unsubstituted (C
2
-C
30
) alkylenoxyhydroxyalkylene residue, a (C
2
-C
30
) alkenyl residue, a substituted or unsubstituted (C
2
-C
30
) alkinyl residue, a substituted or unsubstituted (C
5
-C
30
) cylcoalkylene residue or a substituted or unsubstituted (C
5
-C
30
) arylene residue possibly having one or several heteroatoms, where the residue R
2
each time is bound to an oxygen atom of the anhydro-carbohydrate unit and the degree of substitution x
3
is 0, 1, 2 or 3, where Y is a functional group selected from a nitrate group, an aminodeoxy group, a substituted or unsubstituted amino group, a carboxyalkyl-, a hydroxyalkyl- group, a sulfate-, a sulfonate- group, a carbonate- or xanthogenate-group, the degree of substitution x
2
being 0, 1, 2 or 3, provided that the sum of x
1
, x
2
and x
3
be ≦3 and that x
3
not be 0 over the entire polymer chain and that n be a degree of polymerization between 1 and 10,000, the coupling of the anhydrocarbohydrate units being linear, cyclic, branched or crosslinked.
Only those carbons are meant in the above stated range of carbon numbers of the particular residues which are not double-bonded to oxygen.
In a preferred implementation of the present invention, the anhydro-carbon unit AK is an anhydroglucose unit.
In case the residues R
1
and R
2
resp. denote a substituted aryl residue and a substituted aryloyl residue, these residues illustratively may be substituted by one or several halogen atoms, alkyl residues, cycloalkyl residues, mono-, di- or tri-alkylsilyl residues, mono-, di- or tri-arylsilyl residues or trifluoromethyl groups.
Compared with other polymeric sulfur compounds, the polymeric thiosulfates of the invention offer good solubilities in polar s

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