Sage Journals: Discover world-class research

Abstract

A method based on laser scanning confocal microscopy (LSCM) has been developed for simultaneously obtaining the diffusion coefficient D and the ratio of the convection mass transfer coefficient h_m and the partition coefficient K. This new method, which is demonstrated for a nylon film dyed with a disperse dye, is nondestructive and much faster than previously used methods for obtaining D that neglect the boundary layer effects. Although based on the fluorescence of dyes, this technique is successfully used with real dyes (not model dyes) at industrially relevant concentrations. LSCM is used to quantita tively measure the relative concentration profiles of a dye through a film, and corrections are made for the strong absorption of the incident laser light as it passes through the film. The data are then modeled using known mass transfer relationships to simultaneously obtain D and the ratio h_m/K. Since K is measured in a separate experiment, all three mass transfer parameters are determined.

Get full access to this article

View all access options for this article.

References

Boulton, J. , and Morton, T.H. , Application of Vat Dyes to Viscose Rayon, III: Application of Vat Dyes and Viscose Rayon, J. Soc. Dyers Colour. 55, 481-487 (1939).

Carr, W.W. , Michielsen, S. , Mock, G. , and McCall, B. , Fundamental Investigations of Ultrasonic Effects in Textile Wet Processing, National Textile Center Annual Report: Project G95-13, pp. 173-180, 1997.

Crank, J. , "The Mathematics of Diffusion," 2nd ed., Clarendon Press, Oxford, London, 1975.

Etters, J. Nolan , The Diffusional Boundary Layer: Some Implications for the Dyeing Technologist , J. Soc. Dyers Colour, 97, 170-179 (1981).

Garvie, W.M. , and Neale, S.M. , Absorption of Dyestuffs by Cellulose, VII: Analysis of the Diffusion of Sky Blue FF through Single and Multiple Membranes , Trans. Faraday Soc. 34, 335 (1938).

Hill, A.V. , The Diffusion of Oxygen and Lactic Acid through Tissues, Proc. R. Soc. 104 Ser. B, 39 (1928).

Incropera, F.P. , and Dewitt, D.P. , Fundamentals of Heat and Mass Transfer , 3rd ed., John Wiley & Sons , NY, 1990.

McBain, J.W. , The Mechanism of Adsorption ("Sorption") of Hydrogen by Carbon, Z. Physik. Chemie 68, 471 (1910).

McFarland, E.G. , Michielsen, S. , and Carr, W.W. , Use of a Laser Scanning Confocal Microscope to Obtain Concentration Profiles of a Diffusant in a Polymer Film, Appl. Spectros. 55(4), 481-489 (2001).

10.

McGregor, R. , Peters, R.H. , and Varol, K. , The Physico-chemical Hydrodynamics of Dyeing, I: An Experimental Study of the Convective Diffusion of a Dye to an Absorbing Surface, J. Soc. Dyers Colour. 86(10), 437-442 (1970).

11.

McGregor, R. , Peters, R.H. , and Varol, K. , The Physico-chemical Hydrodynamics of Dyeing II—The Sorption of Disperse Dyes by Films of Methoxymethylnylon 6,6 , J. Soc. Dyers and Colour, 86(10), 442-445 (1970).

12.

McGregor, R. , Nounou, A.E. , and Peters, R.H. , The Effect of Rate of Flow on the Sorption of Dye by a Nylon Fabric from Aqueous Solutions, J. Soc. Dyers Colour. 86, 246-254 (1974).

13.

Michielsen, S. , Aberrations in Confocal Spectroscopy of Polymeric Materials: Erroneous Thicknesses and Intensities, and Loss of Resolution. J. Appl. Polym. Sci. 80, 1662-1669 (2001 ).

14.

Peters, R.H. , Petropoulos, J.H. , and McGregor , R. , A Study of the Diffusion of Dyes in Polymer Films by a Microdensitomeric Tectinique . J. Soc. Dyers Colour. 77, 704 (1961).

15.

Sasaki, H. and Morikawa, H. , Diffusion of an Acid Dye in a Multiple Porous Membrane Assembly, Textile Res. J. 62, 509-516 (1992).

16.

Sasaki, H. , Yanai, E. , and Araki, H. , Correcting Fabric Dyeing Rates by Evaluating Contact Points of Yarns , Textile Res. J. 63, 614-618 (1993).

17.

Sekido, M. , lijima, T. , and Takahashi, A. , Diffusion of Dyes into Nylon Film, A., Kogyo Kagaku Zasshi 68, 524 (1965).

18.

Smith, C.B. , and Thakore, K.A. , Effect of Ultrasound on Fiber Reactive Dye Hydrolysis, Textile Chem. Color. 23(10), 23-25 (1991).

19.

Song, Y. , Study of Dye Diffusion in Fibers by Laser Scanning Confocal Microscopy , Doctoral thesis, North Carolina State University. 1999.

20.

Song. Y. , Srinivasarao, M. , Tonelli. A.. and McGregor. R., Laser Scanning Confocal Microscopy Study of Dye Diffusion in Fibers. Macromolecules 33(12). 5443-5447 (2000).

21.

Thakore. K.A. , Application of Ultrasonics in Dyeing of Cotton Fabrics with Direct Dyes, Part II: Diffusion Kinetics. Ind. J. Textile Res. 13, 208-212 (1988).

22.

Thakore, K.A. Smith, C.B. , and Hite. D. , The Effects of Ultrasound and the Diffusion Coefficient of C.I. Direct Red 81 in Cellulose . Textile Chem. Color. 22, 21-22 (1990).

Determining Diffusion and Convective Mass Transfer Coefficients in Dyeing a Thin Flat Film

Abstract

Get full access to this article

References