Dyestuff Diffusion in Oriented Polypeptide Membranes

Abstract

Diffusion of dyestuff in "oriented" poly(γ-methyl L-glutamate), poly(γ-butyl L- glutamate), and poly(γ-hexyl L-glutamate) membranes was studied. The three poly peptide membranes differ in the widths of the diffusion paths between helical rods. The diffusion of the dyestuff observed as the reduced concentration gradient in the membrane was calculated on the assumption of a concentration-dependent diffusion coefficient. This dependence corresponds to the diffusion with a Langmuir-type ad sorption of dyestuff. The coefficient obtained in the direction parallel to the helical rod is a few times larger than that in the perpendicular direction. The reduced con centration gradient proceeds quickly to the inner part of the membrane when the side chain region is wide. Using electropositive methylene blue and electronegative alizarine red S and acid blue 45, the effects of the electrostatic and structural nature of the dyestuff on the diffusion were examined. Alizarine red S may diffuse rapidly with low concentration dependence, and methylene blue may diffuse slowly with high concen tration dependence. The behavior with acid blue 45 is intermediate.

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References

Crank, J. , "The Mathematics of Diffusion," Clarendon Press , Oxford 1975, p. 112.

Fougnot, C. , and Jozefonvicz, J. , Solution Behavior of Homopolymers and Random Copolymers of L-methionine and S-ethyl-L-cysteine, J. Polym. Sci. C39, 199-209 (1972).

Kinoshita, T. , Okazaki, N. , Takizawa, A. , and Tsujita, Y. , Sorption and Permeation of Poly(n-hexyl L-glutamate)—Organic Solvent Systems, Polymer 20, 791-796 (1979).

Kinoshita, T. , Taniguchi, T. , Washizu, S. , Takizawa, A. , and Tsujita, Y. , Characteristics of Water in Polypeptide Membrane , Polymer J. 12, 475-481 (1980).

Kinoshita, T. , Yamashita, T. , Iwata, T. , Takizawa, A. , and Tsujita, Y. , Ionic Salt Permeabilities and Membrane Potentials of Glutamic Acid-Methyl-L-Glutamate Copolymer Membranes, J. Macromol. Sci. Phys. B22, 1-18 (1983).

Matsukura, T. , Kinoshita, T. , Takizawa, A. , and Tsujita, Y. , Effects of Orientation of Helical Rod and of Electrostatic Nature of Dyestuff on Diffusion in Polypeptide Membrane, Sen-I Gakkaishi 36, T-484-T-492 (1982).

Matsushima, N. , Hikichi, K. , and Kaneko, M. , X-Ray Scattering of Synthetic Poly(α-amino Acid)s in the Solid State, I: Transition and Poly(γ-benzyl L-glutamate) and Poly(γ-methyl L-glutamate), Polymer J. 7, 44-49 (1975).

Takizawa, A. , Hamada, T. , Okada, H. , Imai, S. , and Kadota, S. , Permeability of a Series of Alcohols Through Poly(γ-methyl-D-glutamate), Polymer 15, 157-161 (1974).

Takizawa, A. , Hamada, T. , Okada, H. , Kadota, S. , and Nonoyama, H. , Permeability of Water Vapor and Carbon Dioxide Gas Through Poly (n-alkyl glutamate) , J. Appl. Polymer Sci. 18, 1443-1450 (1974 ).

10.

Takizawa, A. , Taniguchi, T. , Yamamoto, I. , and Tsujita, Y. , Water and Water Vapor Permeation and Solute Separation through Poly(n-alkyl L-Glutamate) Membranes, J. Macromol. Sci. B13, 203-214 (1977).

11.

Wagner, C. , On the Solution of Diffusion Problems Involving Concentration—Dependent Diffusion Coefficients, J. Metals 4, 91-96 (1952).