Bond-Breaking Efficiency of High-Energy Ions in Ultrathin Polymer Films

Abstract

Thin films of poly(methyl methacrylate) and poly(vinyl chloride) of different thickness are used to investigate the effect of spatial confinement on the efficiency of bond breaking induced by 2 MeV H^{+} and 2.1 GeV Bi ions. Effective cross sections for oxygen and chlorine loss are extracted for films down to a thickness of about 5 nm and are compared to theoretical estimations based on radial energy density profiles simulated with geant-dna. The cross sections are to a large extent thickness independent, indicating that bond breaking is dominated by short-range processes. This is in contrast to the strongly reduced efficiencies found recently for cratering induced by high-energy ions in similar ultrathin polymer films [Phys. Rev. Lett. 114, 118302 (2015)PRLTAO0031-900710.1103/PhysRevLett.114.118302].

SAXS data modelling for the characterisation of ion tracks in polymers

“…This eventually leads to the formation of tracks with a lower density compared to the surrounding matrix. 1,53,[92][93][94][95] This mass loss is the main difference between the track structure of polymers and inorganic insulators, and results in the required consideration of the transition region to successfully fit SAXS data for polymers.…”

Reliability and Comparison of Some GEANT4-DNA Processes and Models for Proton Transportation: An Ultra-Thin Layer Study

“…These CDCSs for bond-breaking represent the energy loss by length (dE/dx) [12,13] and are based on the number of specific bond-breaking at the end of an irradiation process. Additional information about the experimental data collection can be found at [14].…”

“…The CDCS was calculated based on the standard thermally activated model (STAM) [16] taking into account the radial deposited energy profile simulated to generate the probability energy deposition function which was adjusted to estimate the activation energy density value for a specific bond-break in N positions [14]. The simulated-calculated CDCS was compared to experimental ones for 2 MeV H þ on PMMA and PVC ultra-thin films.…”

“…DNAopt1 presents larger number of electrons interactions for thicknesses larger than 40 nm with the exception of 20 MeV incident kinetic energy protons beam where the DNAopt2 presents a number of electrons interactions similar to DNAopt1. This behaviour can be explained by the process and model classes evoked by all physics lists evaluated and the maximum kinetic transferred energy to the electrons which was estimated [14] as 4.34 keV for incident protons of 2 MeV, 10.92 keV for incident protons of 5 MeV, 21.90 keV for incident protons of 10 MeV and 44.03 keV for incident protons of 20 MeV. Under these conditions, all transport process classes can be evoked for electrons G4DNAElastic (for DNA and DNAopt2,3,4,and 5) or G4eMultipleScattering (for DNAopt1), G4DNAExcitation, G4DNAIonisation, G4DNAVibExcitation and G4DNAAttachment.…”

Fabrication, thermal analysis, and heavy ion irradiation resistance of epoxy matrix nanocomposites loaded with silane-functionalized ceria nanoparticles

“…13–15 Structural damage and property changes in nanofiller-loaded polymer matrix composites under various irradiation conditions have been well studied, especially for epoxy resins that are commonly used in nuclear energy applications. 16–18 However, the impacts of nanofillers on radiolytic damage processes within the polymer matrix are not well understood. 19–22 Building a detailed mechanistic understanding of heavy ion irradiation damage formation and recovery in nanostructured epoxy matrix composites is needed to guide the development of advanced materials solutions for applications in extreme environments.…”