Analysis of the surface chemistry of oxidized polyethylene: comparison of XPS and ToF‐SIMS

Abstract

A series of low-density polyethylene (LDPE) surfaces, chemically modified using a number of oxidative techniques employed for adhesion enhancement (pretreatments), have been studied by time-of-flight (ToF) SIMS and XPS. The methods consisted of corona discharge, flame, electrochemical, chromic acid, acid dichromate and acid permanganate treatment. All except flame treatment were performed under mild and fairly severe conditions to yield a range of surface chemistries. The XPS analysis, using high energy resolution and a refined approach to C 1s curve-fitting, provided some new insights into the quantitative assessment of the type and concentration of functional groups. Both positive and negative ion ToF-SIMS spectra were obtained at high mass resolution. The oxygen-containing fragments were identified by accurate mass analysis and subjected to a detailed comparison with the XPS results. No convincing relative intensity correlations could be identified that would allow particular secondary ion fragments to be associated strongly with particular functional groups (in this multi-functional surface situation). Inorganic residues resulting from wet chemical treatments were also investigated and here the two techniques were found to be more complementary.

Flame treatment of low-density polyethylene: Surface chemistry across the length scales

“…The oxygen concentration increased with an increasing number of treatments. The surface concentration of oxygen was found to be 10.71% (take-off angle was 608) whereas 12% was detected by Briggs et al in an independent study (take-off angle was 908) [41]. The LDPE film treated 200 times was rinsed for 1 min in a solution of ethanol and water and this procedure resulted in a drop in the O concentration as observed by XPS.…”

“…As has been proposed elsewhere [41,43], flame treatment introduces hydroxyl, carbonyl, and carboxyl groups on the surface of PE films. In addition to giving qualitative atomic concentrations on the sample surface, XPS spectra can also provide chemical bonding information.…”

Surface morphology and chemistry of Prunus laurocerasus L. leaves: a study using X-ray photoelectron spectroscopy, time-of-flight secondary-ion mass spectrometry, atomic-force microscopy and scanning-electron microscopy

“…With decreasing BE the four components have relative peak areas of 1.9, 3.4, 7.6 and 87.1%, respectively. The curve fitting of complex C 1s peaks of this type (resulting from surface oxidation of polyethylene) has been discussed in detail elsewhere (Briggs and Fairley 2002;Briggs et al 2003). It is sufficient to note here that because the hydrocarbon component is inherently asymmetric on the high-BE side the relative intensity of the C-O component is subject to considerable uncertainty and may well be overestimated in this case.…”

Microplastic-Associated Biofilms: A Comparison of Freshwater and Marine Environments

“…To improve our knowledge of the biodegradation of plastics and plasticsorbed pollutants, such approaches could be supplemented by advanced surface analysis techniques. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) have been used to investigate abiotic weathering of plastics [96][97][98] and could be valuable for monitoring polymer biodegradation (Fig. 3).…”

“…3). Indeed, XPS can detect chemical signatures at the parts-per-thousand (‰) range [96], and SIMS (including nanoscale SIMS) has been used to trace microbial uptake of 13 C-labeled substrates in environmental samples [99,100]. While these techniques are suitable for analyzing organic compounds, X-ray diffraction (XRD) analyses are particularly useful for measurements of inorganic materials, including metals.…”