Lm. Kukreja et P. Hess, PHOTOACOUSTIC DETECTION OF THE DECOMPOSITION KINETICS OF POLYMERS - INTERPRETATION OF ACOUSTIC-SIGNALS, Applied surface science, 80, 1994, pp. 399-402
Citations number
12
Categorie Soggetti
Physics, Condensed Matter","Chemistry Physical","Materials Science, Coatings & Films
A broadband piezoelectric PVDF foil transducer was used for time-resol
ved detection of the acoustic signals generated by laser-induced ablat
ion of polyimide. The fast signal observed within the time resolution
of the detection system of several nanoseconds was assigned to thermoe
lastic excitation. The second, strongly fluence-dependent acoustic sig
nal with a delay varying between 5 and 500 ns was observed for the fir
st time and interpreted as due to the recoil momentum of the ablating
species. The corresponding delay times measured for polyimide and KrF
(248 nm) and XeCl (308 nm) radiation correlate with the deposited ener
gy density. This interpretation is not in agreement with previous assi
gnments and points to much longer delays for the ejection of particles
at low fluences.