UV-vis -infrared optical and AFM study of spin-cast chitosan films

Authors

W H. Nosal, Department of Electrical Engineering, University of Nebraska- Lincoln
D. W. Thompson, University of Nebraska- LincolnFollow
Sabyasachi Sarkar, Department of Chemical and Biomolecular Engineering, University of Nebrska Lincoln
Anuradha Subramanian, Department of chemical Engineering,University of Nebraska Lincoln.Follow
John A. Woollam, University of Nebraska-LincolnFollow
L Yan, Department of Electrical Engineering, University of Nebraska- Lincoln

Date of this Version

6-1-2005

Comments

This article was publishe in Colloids and Surfaces B: Biointerfaces Vol. 43, 2005, pp 131-137. Copyright © 2005 Elsevier Inc. All rights reserved. Published version of this article is available at Science Direct

Abstract

Optical properties OS spin-cast chitosan films have been determined in the infrared, visible, and ultraviolet region or the spectrum ~tsing spectroscopic ellipsometry. Optical constants for the Vvis-near IR spectra from 130 to 1700 nm were determined using Cauchy dispersion forms com-bined with Lorentzian oscillator models in the absorptive shorler wavelength regions. Infrared ndex of refraction and extinction coefficients from 750 to 4000cm-' were determined using ellip-sometric data fits to dispersion models based on harmonic oscillators. This modeling determined that optical onisotropy was present and measurable over all wavelength regions of ellipsomctric data. To obtain information on the micro- and nano-scale surface structure, tapping mode atomic force microscopy (AFM) imaging was employed to determine morphology and roughness infor-mation of dry spin-cast chitosan films.