Polymer substrate-laser interaction

Multiphase composites formed of polymer substrates coated with thin metal films show special properties and are in great demand for various applications. The metal-polymer substrate interaction and the morphological structure at the interface influence the final properties of the composites of thin metal-polymer substrates. Thus, modifying the properties of the polymer substrate by wet (acid, alkali), dry (plasma), and radiation treatments (ultraviolet radiation and laser) appears as a significant step for increasing adhesion of thin film onto polymeric substrates. 

All mass spectra were obtained with a Fourier transform ion cyclotron resonance mass spectrometer (FTMS). The theory and applications of FTMS spectrometry are well-established and will not be discussed here. In our apparatus the sample was located at one of the trap plates of the cell, inside a superconducting magnet. Two pulsed lasers were used, one for tire PFPE desorption and another for metal ion formation. Typically, 2 to 4 mj/pulse of 248 nm or 193-nm light (20 ns fwhm) from an excimer laser was softly focused to an elliptical spot with a 2-mm long axis for desorption. To create the metal ions, a 0.3-mJ pulse of 532-nm light (10 ns fwhm) from the doubled output of a Nd YAG was tightly focused. The metal substrates were prepared from foils of various metals (typically 0.010 in. tiiick). Surface preparation was not critical because the experiment was not sensitive to PFPE/metal surface interactions since the thickness of the polymer films was on the order of 1 pm. 

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