Photo-oxidation resistance

On the contrary, the organoclay improved the photo-oxidation resistance of the OMMT-fiUed PE/PA blends [141] and PVC-laponite nanocomposites [142]. 

Fig. 37. Resist images obtained with a cross-linking monocomponent TSI resist (PHOST polymer), cross-linked by photo-oxidation using light at 193-nm wavelength. After exposure, the film was treated with a vapor of dimethyl silyl dimethyl amine and then plasma developed using O2—RIE (122).

Johnson, M.P., Havaux, M., Triantaphylides, C., Ksas, B., Pascal, A.A., Robert, B., Davison, P.A., Ruban, A.V., and Horton, P. 2007. Elevated zeaxanthin bound to oligomeric LHCII enhances the resistance of arabidopsis to photo-oxidative stress by a lipid protective, anti-oxidant mechanism. J. Biol. Chem. 282 22605-22618. 

The most frequently used substances for n-doping of hematite are oxides of silicon and titanium. Photo-oxidation of water at Si- and Ti-doped hematite has accordingly been studied extensively [1, 6, 7, 12, 18, 20, 21, 61]. In general, the conductivity is improved by these dopants. However, there seems to be a limit for the improvement by doping. For example, concentrations over 0.5 atom percent of titanium in hematite have been stated to have no effect on the resistivity [7]. 

Organic layers are deposited mainly by thermal evaporation or spin coating from solutions for small molecule or polymeric materials, respectively. Metal layers are usually made by thermal evaporation. All layers should be chemically stable, especially under the device operating conditions, and resistant to oxidation or photo-oxidation. 

In most cases, the iodide-triiodide redox couple has been employed (presumably because of its success in shuttling the photo-oxidized dye in the sensitization experiments) although other redox electrolytes e.g., SCN /(SCN)2 , [342] have also been employed. For the chalcogenide films, sodium selenosulfite was employed [319]. It must be noted that, aside from losses due to the surface recombination and back-reactions, an additional loss component from the increase in film resistance must also be recognized especially as the film thickness is increased. The resistance loss manifests as a deterioration in the photovoltage and fill factor. 

Methacrylates are exceptionally stable to ultraviolet (UV) light and to oxygen owing to the absence of tertiary hydrogens on the polymer chain which prevent photo-oxidative and thermo-oxidative attack. Acrylate ester polymers are somewhat less resistant to both UV light and thermal oxidation owing to the presence of tertiary hydrogen atoms. 

Highly oriented PP monofilaments (drawn to break at 25 ) are more resistant to photo-oxidation than medium drawn fiber ( x5 orientation at 230 C) as measured both by oxidation product build up and mechanical deterioration (2 ). Both types of PP monofilaments also show crack formation during photooxidation CFlgure 7). The lower orientation material shows quite wide, deep cracks whereas the fully oriented fiber shows many short, narrow cracks for... 

Dioxane is a cyclic ether compound that is miscible with water in all proportions and is also moderately volatile. It is resistant to hydrolysis and microbial degradation, but may undergo photolysis at water and soil surfaces. An estimate of the half-life for abiotic degradation in water with addition of ozone was 60 h. The half-life for photo-oxidation in air was 3.4 h. 1,4-Dioxane has a low adsorption potential and a high mobility/leaching potential in soil/water systems. No bioaccumulation of this chemical is expected. 

Cresol-formaldehyde, phenol-formaldehyde, and chlorinated cresol-formaldehyde novolac resins all undergo photo-oxidation upon UV-irradiation in air. The change of the carbon core level signals is shown in Fig. 8. The new IR band at about 1720 cm-, corresponding to formation of a carbonyl group, is also found after photo-oxidation of novolac resin. These oxidized layers of the novolac film are limited to a very shallow superficial surface only about 500 A thick, even after long deep UV irradiation, as discussed below in reference to photostabilization of resist images. 

---