Laser Irradiation of Polymer-Doped Cryogenic Matrices

Interactions between intense (10¹⁹ photons/cm² per shot) UV laser light and doped ice matrices were studied by the Matrix-Assisted Pulsed Laser Evaporation (MAPLE) deposition technique. Water, isopropanol, acetone and toluene ice matrices have been used as hosts for the biotechnologically important polymer – polyethylene glycol (PEG). The polymer–matrix system was irradiated under vacuum conditions with high-intensity laser beam at 355 nm in the fluence range 2–10 J/cm². We have explored the ejection of material from the ices in terms of light absorption by the matrix and photochemical interactions between matrix and polymer molecules during the irradiation process. The transfer of polymer from the matrix to a substrate has been studied on the basis of deposition rates measured with a quartz crystal microbalance (QCM) and Fourier-Transform Infrared (FTIR) spectra recorded from the deposits.