Surface Characterization and Thermodynamics of Adsorption of Congo Red-gelatin Laver-by-Laver Growth

  • Rosemary S. Turingan Advanced Physical Chemistry Research Laboratory, Institute of Chemistry, University of the Philippines, Diliman, Quezon City
  • Ma. Cecilia P. Garcia Advanced Physical Chemistry Research Laboratory, Institute of Chemistry, University of the Philippines, Diliman, Quezon City
  • Leon M. Payawan Jr Advanced Physical Chemistry Research Laboratory, Institute of Chemistry, University of the Philippines, Diliman, Quezon City
  • M. Cynthia Goh Department of Chemistry, University of Toronto, Ontario
Keywords: layer-by-layer growth, Congo Red, Gelatin, adsorption isotherm, contact angle, spectroscopy, Atomic Force Microscopy

Abstract

Gelatin, a denatured fonn of collagen was made cationic at a pH below its isoelectric point. With Congo Red as an anionic bolamphiphile, layer-by-layer assembly of dye-polyelectrolyte was made possible through electrostatic alternate adsorption. Effects of pH, concentration, and ionic strength were investigated to attain the optimum conditions for layer growth. Films fabricated were characterized using UV-Spectroscopy, Atomic Force Microscopy (AFM), and contact angle measurements. The extent of layer build-up was correlated with the dye's absorbance at A = 497 nm and it was found out that as more layers were deposited, a corresponding increase in absorbance was observed. Surface topology was studied through AFM and comparative contact angle measurements of the undeposited and deposited substrate were conducted. An increase in the wettability was associated with the adsorption of the hydrophilic layers on glass. Adsorption isotherms were constructed through the relation between amount adsorbed as a function of the bulk sample concentration.
How to Cite
Turingan, R. S., Garcia, M. C. P., Payawan Jr, L. M., & Goh, M. C. (1). Surface Characterization and Thermodynamics of Adsorption of Congo Red-gelatin Laver-by-Laver Growth. KIMIKA, 17(2), 65-70. https://doi.org/10.26534/kimika.v17i2.65-70
Section
Research Articles