Figure 2 shows a synthetic model for this data envelope where three GL peaks have been added, then fitted using a Marquardt-Levenberg optimization algorithm. If Gaussian/Lorentzian (GL) line-shapes are added in an arbitrary way, the Curve fit yields little information about the sample other than to say that it deviates from the published data for PAA and therefore demonstrates the presence of additional chemistry at the surface. Figure 1: C 1s high-resolution spectrum taken from a polymer -based sample using a VG ESCALAB 220i at University College London, UK.Ģ The high-resolution spectrum in Figure 1 derives from poly (acrylic acid) PAA reacted with inorganic material (or partially reacted) in an acid-base reaction. A typical C 1s envelope (Figure 1) includes structure that offers chemical information about a sample, but without some initial starting point it is difficult to construct an appropriate model for such a data-envelope. 1 Curve Fitting and Polymers The availability of data from well-characterized samples such as those offered by Beamson and Briggs owe much to the popularity of XPS as a tool for understanding the chemistry of Polymers.
