Abstract
Scanning Probe Microscope (SPM), that is, Atomic Force Microscope equipped with a detection system for various mechanical features was applied to observe separated domains of SB-latex and starch in their blend film based on the different levels of “hardness” between the two binder regions. This method has a merit that there is no need to stain SB-latex with Osmium or Bromide, and starch with Iodine. Besides, it permits us to observe samples at very high inplane resolutions and in atmospheric circumstances. Empirically, the elastic modulus image of SPM showed small particles 0.2 μm in diameter that seem to be uncoalesced latex particles on a surface. But, those particles were hardly seen in the topographic image presumably because the particles are buried in the film with the coalescence interface shape mostly maintained. The phase mode image in the tapping mode revealed stripes running at 1.5 gm intervals, which are likely to correspond to domains of the two binders. Transmission electron microscopy confirmed that the stripes are due to the alternate separated domains. Thus, SPM, when applied to coated paper, has a feasibility to assess SB-latex and starch distributions in coatings.
