ToF-SIMS characterization of modified starch on fine and LWC base papers

The surface chemistry of starch-coated fine and LWC papers was studied using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The starch was modified by varying the degree of acetylation and cationization and spread onto paper surfaces by spraying or bar coating. ToF-SIMS imaging showed a substantially more uniform coating layer of starch when bar coating was used. The spatial distributions of acetyl and quaternary nitrogen functional groups were also assessed. A direct relation between the theoretical cationization/acetylation ratio and the peak ratios obtained by ToF-SIMS indicated that the starch characteristics can significantly influence the surface chemistry of paper. Furthermore, some benefits and drawbacks of this novel characterization technique, especially with regard to quantification of the spectral information, are discussed.