109. Preparation and Properties of Infrared Heat-Sensitive Polymer Nanoparticles

Polymer nanoparticles containing near-infrared absorbing dye (maximum absorption at about 830 nm) were prepared by a two-staged emulsion copolymerization of styrene (ST), acrylonitrile (AN), and benzoic acid in the presence of sodium dodecyl sulfate. After the two-staged polymerization process, the conversion rate can be increased to 96 % or higher. The emulsion was stable, and little precipitation was observed. The prepared polymer nanoparticle was characterized with TEM, UV-Vis spectroscopy, DSC, and TGA. Thin coatings were prepared with the IR830-containing emulsion and a small amount of other additives. The polymer nanoparticles in the coating would keep the original spherical structure and clear outline could be observed, provided that the coating was dried at a proper temperature, such as at 100 °C or at a lower temperature. However, the infrared dye-containing polymer nanoparticles would be readily fused under image-wise IR laser exposure (exposure dose: 200 mJ/cm2). As a result, the laser-exposed areas of the coating firmly adhered to the substrate and showed enough resistance to water flushing, whereas the non-exposed areas were easy to develop.