AVS 46th International Symposium
    Applied Surface Science Division Thursday Sessions
       Session AS-ThA

Paper AS-ThA6
Quantitative Analysis of Functional Groups with TOF-SIMS

Thursday, October 28, 1999, 3:40 pm, Room 6A

Session: Polymer Surfaces, Films, and Interfaces
Presenter: T. Fladung, Universität Münster, Germany
Authors: T. Fladung, Universität Münster, Germany
D. Wolany, Universität Münster, Germany
T. Gantenfort, Universität Münster, Germany
L. Wiedmann, Universität Münster, Germany
A. Benninghoven, Universität Münster, Germany
Correspondent: Click to Email
The unique identification and quantitative analysis of functional groups from plasma treated polymer surfaces with XPS and TOF-SIMS is often difficult. In this case, derivatization and subsequent quantitative XPS is well-known for a number of important functionalities. We will show that the analysis of derivatization products with TOF-SIMS can extend the limited sensitivity of XPS by several orders of magnitude and, at the same time, be made quantitative by suitable calibration. After gas phase derivatization of hydroxide groups with trifluoroacetic anhydride (TFAA), the XPS results of monofunctional model polymers can be used as standards for the calibration of SIMS data. During TOF-SIMS analysis of the model polymers after derivatization, the intensity of a characteristic set of molecular ions containing fluorine is proportional to the concentration of OH groups as determined by XPS, and can thus be taken as a quantitative measure of the surface concentration of OH groups. For polypropylene and polycarbonate samples treated in an oxygen and argon plasma, respectively, the modified surfaces were derivatized with TFAA and analyzed with XPS and TOF-SIMS. The results were used to quantitatively distinguish the OH groups from other functionalities generated by the plasma such as carbonyl or carboxyl groups. Principal component analysis was used for the comparison of SIMS spectra before and after derivatization. This seems to be a promising way to establish a direct assignment of secondary ions to specific functional groups. In this way the quantitative chemical analysis of surface functionalities by TOF-SIMS should become possible without derivatization.