The effect of the molecular size on the absorption spectra of macromolecules

• Published in: Macromolecules Vol. 20; no. 12; pp. 3070 - 3075
• Main Author: Garcia-Rubio, L. H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.12.1987
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Chemical solution; Experimental test; Influence; Polymer; Styrene polymer; Molecular weight; Absorption spectrum
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma00178a022

The applications of the theory of scattering of electromagnetic radiation to the estimation of the absorption coefficients of macromolecules such as polystyrene resins yield values for the absorption coefficients that are considerably different from those obtained from the direct application of Beer--Lambert law. The differences in absorption coefficients can be explained in terms of the size and the optical properties of the macromolecules. The effects of the molecular size on the absorption spectra of macromolecules are reported, using as a basis the theory of electromagnetic radiation. As a result of this investigation, the conditions for the strict correspondence between Mie theory and Beer--Lambert law have been derived. A sensitivity analysis is conducted to define the limits of application of Beer--Lambert law and the conditions required to extract size information from transmission measurements in the region of intrinsic chromophore absorption. As case studies, the UV/vis spectra of well-characterized polystyrene standards have been investigated. 19 ref.--AA