SURFACE-ANALYSIS BY LASER IONIZATION APPLIED TO POLYMERIC MATERIAL

Single-photon ionization surface analysis by laser ionization (SPI-SALI) coupled with a static primary ion beam or a soft laser beam for desorption is a promising new method for the characterization of polymer surfaces. SPI-SALI combines nonresonant photoionization of desorbed or sputtered neutral atoms and molecules with analysis by time-of-flight mass spectrometry in ultrahigh vacuum. Stimulated desorption is accomplished by an ion source (Cs+, Ar+, or Ga+), electron gun, or laser-induced desorption (CO2 or Nd:YAG). Single-photon ionization using 118-nm light is useful for identifying polymer material, such as polyethylene glycol, polystyrene, polydimethyl siloxane, and many others, by the ease of the monomer identification.