Surface modifiers sensitization mechanisms

A subset of electron-hole radical pairs exhibits features of Spin Correlated Radical Pair (CRRP) electron spin polarization mechanism [101] which can be observed at somewhat longer times via light/field modulated (LFM) EPR measurements. This technique is only sensitive to the light dependent part of the EPR spectrum on the time scale of the light modulation frequency (millisecond regime, insert Fig. 1.15). Using LFM EPR it was observed that both the transitions of the holes localized on the surface modifier and electrons localized on the Ti02... 

The purpose of this work was to increase the A3 selectivity at low conversion through a catalyst modification. Previous studies of phenol alkylation with methanol (the analogue reaction) over oxides and zeolites showed that the reaction is sensitive to acidic and basic properties of the catalysts [3-5]. It is the aim of this study to understand the dependence of catalyst structure and acidity on activity and selectivity in gas phase methylation of catechol. Different cations such as Li, K, Mg, Ca, B, incorporated into y-Al203 can markedly modify the polarisation of the lattice and consequently influence the acidic and basic properties of the surface [5-8] which control the mechanism of this reaction. 

The first BioCD took its inspiration from the compact disc. The compact disc was invented in 1970 by Claus Campaan of Phillips Laboratory. The concept is purely digital and uses null interferometers that are far from quadrature, as appropriate for the readout of two binary intensity states. The interferometers were common-path and stable, as required for the mechanical environment of portable compact disc readers. The original BioCD used the same physics as the compact disc, but modified the on-disc microstructures to change from the digital readout to an analog readout that operated in quadrature for sensitive detection of surface-bound proteins7,8. Because the quadrature condition is established by diffraction off of microstructures on the disc, this is called the microdiffraction-class (MD-Class) of BioCD. 

The characterization of the surface chemistry of the modified polymer is one step in understanding the mechanism for cells adhesion. The next crucial step is to determine the nature and extent of chemical interactions between the overlayer of interest and the modified polymer surface. This step presents a challenge because cmrently there are no techniques available with the sensitivity to characterize chemical interactions for an atomically thin buried interface. Several approaches have been used to analyze buried interfaces. Ion sputter depth profiling (typically done with Ar ions) in conjunction with XPS can be used to evaluate a buried interface for overlayers >10 nm [2]. 

Chapter 6 takes the much studied supramolecular dye-sensitized TiC>2 as an example of an operational supramolecular interfacial device. The fundamental operation of these devices are discussed, including their mechanism of operation. The application of modified semiconductor surfaces as electrochromic devices is also considered. 

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