Chemical damage in poly(phenylene sulphide) from fast ions: Dependence on the primary-ion stopping power

Abstract

Thin poly͑phenylene sulphide͒ foils were bombarded with fast atomic ions ͑ 4 He, 12 C, 16 O, 32 S, 79 Br, 127 I͒ in the energy range between 2.5 to 78 MeV. In order to maintain the same ion track size for all impacting ions, their initial velocity was kept constant at 1.1 cm/ns. Under these conditions the deposited energy density in a single ion track changes as a result of the varying stopping power (dE/dx) of the projectiles in the material. Fourier transform infrared spectroscopy and UV-visible spectroscopy were used to characterize the irradiated targets. Damage cross sections ͑ ͒ for different chemical bonds, such as C-S and ring C-C bonds, are extracted from the IR data. For all analyzed IR bands, the values of scale roughly with the square of dE/dx ͑energy density in a single ion track͒. The absorption of the irradiated samples in the visible and UV region increases as a function of fluence. The rate of increase of absorption at a particular wavelength scales also as (dE/dx) n with nϷ2. The observed nonlinear dependence of the damage cross sections on the deposited energy density is considered in the light of two models: a statistical model based on the fluctuations of the energy deposited by the primary ions ͑hit theory͒ and an activation ͑thermal spike͒ model. It is found that the damage cross section is not determined directly by the initial deposited energy density distribution. The best agreement between experiment and theory is obtained when transport of the deposited energy occurs.

Measurement of MeV Ion Track Structure in an Organic Solid

“…The radial variation of the mean deposited energy density at the time of ejection obtained here appears to be less steep than the theoretical r 22 dependence obtained for the initial energy density in the track of fast ions in a gas. This dependence is in rough agreement with recent modeling of ion tracks in polymers [25].…”

“…The effect on the velocity distributions should be small, as ͗y 2 x ͘ and ͗y x ͘ increase slowly with dE͞dx, the stopping power [24]. However, previous data on the damage cross section obtained for polymer films indicate an increase in the cross sections of up to a factor of 2 for 55 MeV I bombardments compared to 78 MeV I ions [25]. To account for these differences the radii in Fig.…”

“…3(a) and 3(b) that the near-surface energy density in the track produces fragmentation and ejection processes that are closely intertwined. The local energy density triggers the fast "hot" chemistry responsible for bond rearrangement in the track [25]. However, the dependence of the mean velocity of the ions with the place of emission indicates ejection occurs in response to the volume force arising from the energy density gradient in the track [26].…”

Removal of arsenic(III) and arsenic(V) on chemically modified low-cost adsorbent: batch and column operations

“…4, a number of absorption peaks for SCC observed at 3,424, 2,927, 2,858, 1,576, 1,420, 1,260 and 781 cm -1 represent N-H stretching of primary aromatic amine, [CH 2 asymmetrical stretching, symmetrical stretching [CH 2 group, skeletal vibration of aromatic C=C, deformational vibration of =C-H of alkenes, C-N stretching of aromatic primary amine and -C-H out of plane deformation of aromatic compounds, respectively (Kemp 1996;Furniss et al 2005;Ghosh 2006). After treatment with thioglycolic acid, a significant decrease of these bands was noted in the spectrum of TSCC along with two new peaks at 1,702 and 1,094 cm -1 indicating C=O stretching of saturated acid (Furniss et al 2005;Ghosh 2006) and C-S axial stretching (Papaleo et al 1996) of thioglycolic acid. Moreover, the absence of the characteristic frequency at 1,420 cm -1 also shows the existence of structural disorder which has been explained as a result of chemical interaction between alkene groups of SSC and thioglycolic acid at its surface.…”

SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence – Application to luminescence degradation of a fast plastic scintillator

“…More specifically, under low <(dE/dx) e > irradiations, aromatic polymers show a very good radiation resistance, orders of magnitude higher than those of aliphatic compounds. However, it has been shown that in several aromatic polymers (polystyrene [26,27], polycarbonate [28], polyethylene terephthalate [29] and poly(pphenylene sulphide) [30,31]) that the disruption rate of chemical bonds is strongly enhanced when increasing the ion stopping power. Such effect is hence expected in BC-400 which has an aromatic polymer matrix.…”