This paper provides a description of the transmission function of an X‐ray photoelectron spectroscopy (XPS) instrument operating with exchangeable Al Kα (1486.6 eV) and Ag Lα (2984.3 eV) sources. Both sources use the same quartz crystal monochromator and illuminate the same area of the sample. The transmission‐function–corrected data from sputter cleaned gold provides a useful reference material to calibrate other instruments of the same type. Sensitivity factors for Ag Lα and Al Kα are calculated from photoionisation cross sections and electron effective attenuation lengths. These compare well with previous experimental values and data acquired from ionic liquids. The intensity of the Ag Lα source is found to be approximately 50 times lower than the Al Kα source. This, coupled with generally lower photoemission efficiencies, results in noisier data or extended acquisition times. However, there are clear advantages to using the Ag Lα source to analyse certain elements where additional core levels can be accessed and for many technologically important elements where interference from Auger electron peaks can be eliminated. The combination of calibrated data from both sources provides direct and easily interpreted insight into the depth distribution of chemical species. This could be particularly important for topographic samples, where angle resolved experiments are not always helpful. We also demonstrate, using thin coatings of chromium and carbon, that the inelastic background in Ag Lα wide‐scan spectra has a significantly increased information depth compared with Al Kα.

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An instrument has been developed for monitoring cure processes under microwave heating conditions. The main function of the instrument was a calorimeter for performing microwave thermal analysis. A single model resonant cavity was used as the heating cell in the microwave calorimeter. Thermal analysis measurements were obtained by monitoring the variation in the microwave power that was required to maintain controlled heating of the sample. The microwave thermal analysis data were analogous to conventional differential scanning calorimetry measurements. The dielectric properties of the sample, as a function of the extent of cure, have been obtained using perturbation theory from the changes in resonant frequency and quality factor of the microwave cavity during heating. Additionally, remote sensing fibre-optic probes have been employed to measure real time in situ infrared spectra of the sample during the cure reaction. In this paper, we describe the design and operation of the microwave calorimeter. Examples of experimental results are also presented.

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Mechanically robust photocatalytic titanium oxide coatings can be deposited using reactive magnetron sputtering. In this article, we investigate the effect of doping on the activity of reactively sputtered TiO 2 . Silver, copper and stainless steel targets were used to co-deposit the dopants. The films were characterised using XRD, SEM and EDX. Adhesion and mechanical properties were evaluated using scratch testing and nano-indentation, respectively, and confirmed that the coatings had excellent adhesion to the stainless steel substrate. All coatings showed superhydrophilicity under UV irradiation. A methylene blue degradation test was used to assess their photocatalytic activity and showed all coatings to be photoactive to varying degrees, dependent upon the dopant, its concentration and the resulting coating structure. The results demonstrated that copper doping at low concentrations resulted in the coatings with the highest photocatalytic activity under both UV and fluorescent light irradiation.

The cure of an epoxy resin system, based upon a diglycidyl ether of bisphenol-A (DGEBA) with HY917 (an acid anhydride hardener) and DY073 (an amine-phenol complex that acted as an accelerator), was investigated using a conventional differential scanning calorimeter and a microwave-heated power-compensated calorimeter. Dynamic cure of the epoxy resin using four different heating rates and isothermal cure using four different temperatures were carried out and the degree of cure and reaction rates were compared. The cure kinetics were analyzed using several kinetics models. The results showed different activation energies for conventional and microwave curing and suggested different reaction mechanisms were responsible for curing using the two heating methods. Resins cured using conventional heating showed higher glass transition temperatures than did those cured using microwave heating. Kinetics analysisThe reactions taking place in an uncatalyzed acid anhydride-cured epoxy system include monoester, diester, and ether formation, as seen in Scheme 1. 12Correspondence to: R. J. Day (richard.day@manchester.ac.uk).

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ABSTRACT:The cure of a commercial epoxy resin system, RTM6, was investigated using a conventional differential scanning calorimeter and a microwave-heated calorimeter. Two curing methods, dynamic and isothermal, were carried out and the degree of cure and the reaction rates were compared. Several kinetics models ranging from a simple nth order model to more complicated models comprising nth order and autocatalytic kinetics models were used to describe the curing processes. The results showed that the resin cured isothermally showed similar cure times and final degree of cure using both conventional and microwave heating methods, suggesting similar curing mechanisms using both heating methods. The dynamic curing data were, however, different using two heating methods, possibly suggesting different curing mechanisms. Near-infrared spectroscopy showed that in the dynamic curing of RTM6 using microwave heating, the epoxy-amine reaction proceeded more rapidly than did the epoxy-hydroxyl reaction. This was not the case during conventional curing of this resin.