UV/ozone treatment

Recently, Genzer and coworkers [85] presented an interesting new approach for the preparation of stable silane-based SAM systems. As a substrate, cross-linked polydimethylsiloxane (PDMS) was oxidized by UV/ozone treatment to yield a thin sihcon dioxide surface. The surface was then treated with fluorinated alkyltrichlo-rosilanes from the gas phase while being mechanically stretched by a certain length Ax. After modification, the elastomer was allowed to relax resulting in a mecdianically assembled monolayer (MAM) at the surface (Fig. 9.8). 

Fig. 9.8 Schematic illustration of the preparation of mechanically assembled monolayers (MAMs). (A) A cross-linked PDMS film is (B) mechanically stretched by Ax (C), oxidized by UV/ozone treatment to yield a thin Si02 sur-...

When the effects of UV/ozone treatment on the degradation of protocatechuic acid were compared with the rates of six other advanced oxidation processes (AOPs), the UV/ozone process ranked second behind only the UV /03/H202 process in terms of oxidation kinetics. The combination of UV irradiation and ozone was more effective than either UV or ozone alone in terms of degradation rates of protocatechuic acid. The contribution of different reaction pathways in a combined system will be discussed in detail in Chapter 14. 

Adams, C.D., Fusco, W., and Kanzelmeyer, T., Ozone, hydrogen peroxide/ozone and UV/ozone treatment of chromium- and copper-complex dyes decolorization and metal release, Ozone Sci. Eng., 17, 149-162, 1995. 

Vollmuth, S. and Niessner R., Degradation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans during the UV/ozone treatment of pentachlo-rophenol-containing water, Toxicol. Environ. Chem., 61, 27-41, 1997. 

On the other hand, the progress of wet-processes as preparative techniques of metal oxide films has been remarkable. The so-called soft solution process that provides oxide layers by means of electrochemical oxidation of a metal surface is expanding as a synthetic method of various mixed metal oxides with controlled thickness [2], The two-dimensional (2D) sol-gel process based on the hydrolysis of metal alkoxides at the air/water interface has been reported as a preparative technique of ultrathin oxide films (Fig. 6.1a) [3]. It is also known that LB films of metal complexes of long-chain alkyl carboxylic acid can be converted to metal oxide films after removal of organic component by oxygen plasma [4] and UV-ozone treatments (Fig. 6.1b) [5]. Preparation of metal oxide... 

Sample Preparation Spin-coating and UV Ozone Treatment [28]... 

The effect of the surface treatment for longer UV—ozone treatment times (60 min, water contact angle <30°) in terms of adherence and the laterally inhomogeneous distribution of pull-off forces provide evidence for the successful and complete oxidation of the previously hydrophobic PDMS surfaces. Upon storage in ambient conditions, one can observe that the forces gradually increase in heterogeneity with... 

Finally, XPS shows no traces of other elements. In particular, neither Cl nor S were detected, which is important since the PS particles contain sulfate groups and NaCl was added to the particle suspension during the preparation all of these elements can influence the catalytic activity dramatically [1]. In circumstances where the O2 plasma may be causing irreversible damage to the sample, care has to be taken, for example, to avoid volatilization of the catalyst (as with Ru). A milder way of removing the PS mask is to employ an UV/ozone treatment, i.e., irradiation of the sample, kept in pure O2 or air, with a UV lamp creating ozone [108],... 

Here, we give an example where the electrochemical and electrocatalytic properties of nanostructured Pt catalysts supported on glassy carbon, prepared with colloidal lithography, were tested with oxidation of preadsorbed CO, so-called CO-stripping, as a test reaction [99]. The Pt nanoparticles were prepared as described in Fig. 4.11, except that the polystyrene particles were removed by UV-ozone treatment. The particles had an average diameter of 122 11 nm and were about 40 nm high. There was no indication (by AFM... 

Hole injection from the anode into the HTL depends upon the energy barrier at this interface. The higher the barrier, the larger the voltage required to induce injection. Therefore, in order to reduce the barrier (i.e., increase anode work function) and facilitate hole injection, for the typical anode material, indium tin oxide (ITO), various treatments of the surface are used, such as oxygen (O2) plasma treatment UV/ozone treatment treatment with polymerization of and CF4/O2 plasma treatment. ... 

The use of UV/ozone treatment to break down the surfactant at room temperature in air has also been shown to completely remove surfactant from the pores both for mesoporous powders, and for thin films. Silica condensation is promoted by the UV light, simultaneously with surfactant removal. UV light in conjunction with dilute hydrogen... 

Fig. 66. Octadecyltrichlorosilane molecule (OTS, CigH37Cl3Si) (length = 26 A) (a) AFM noncontact topography image of self-assembled OTS film on Si c/Si(lll) 1.0 /xm, A/ = —54 Hz (at 740 Hz), amplitude = 0.2 V. The apparent height of the islands is 16 A, (b) Simultaneously acquired damping image (c). The Si surface was activated by UV/ozone treatment prior to exposure. The time of exposure was 20 s and the age of the OTS solution 10 min.

Clark T, Ruiz JD, Fan El, Brinker CJ, Swanson BJ, Parikh AN. 2000. A new application of uv ozone treatment in the preparation of substrate supported, mesoporous thin films. Chem Mater 12 3879 3884. 

The micropatterning of PAMAM dendrimers relies on (xCP with a hy-drophilized stamp. An UV/ozone treatment increases the surface energy of the PDMS [159,160] and thus provides the necessary homogeneous loading of the stamp (Fig. 16). Contact mode AFM height and friction images recorded on micropatterned dendrimer surfaces show that elevated areas... 

Najafi, E., Kim, J.Y, Han, S.H., and Shin, K. (2006) UV-ozone treatment of multi-walled carbon nanotubes for enhanced organic solvent dispersion. Colloids Surf, A, 284, 373-378. 

Effects of UV/ozone treatment of a polymer dielectric surface on the properties of pentacene thin films for organic transistors. /. Appl. Phys., 104 (1), 013715. 

Golczak, S., Kanciurzewska, A., Langer, J.J., and Fahlman, M. (2009) Degradation of microporous polyaniline film by UV-ozone treatment. Polym. Degrad. Stab., 94 (3), 350-354. 

Silicon wafers were cleaned by ultra-sonication in CHCI3 and ultraviolet (UV)/ ozone treatment. QCM chips (optically polished square-shaped AT-cut quartz crystals (1x1 cm ) with gold electrodes) (Seiko EG G, Seiko Instruments Inc.) were similarly cleaned. On the cleaned chip, Cr and then Si02 were deposited in vacuum with the thicknesses of 5 and 40 nm, respectively. 

The use of UV in the presence of ozone is illustrated by the conversion of portions of PDMS surfaces to more hydrophilic SiO. - UV/ozone treatments were also used to make poly(vinylmethylsiloxane) surfaces more hydrophilic, but only about one-twentieth the PDMS exposure time was required. Such treatments have also improved the permeability of PDMS membranes. ... 

Studies of this restructuring process have been carried out on PDMS with surfaces made hydrophilic by UV/ozone treatment, oxygen plasma, or corona discharge. In these cases, changes in surface composition were determined using chemical force microscopy,Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy, or atomic force microscopy. ... 

Egitto, F. D. Matienzo, L. J., Transformation of Polyfdimethylsiloxane) into Thin Surface Films of SiO by UV/Ozone Treatment. Part I Factors Affecting Modification. J. Mater. Sci. 2006, 41, 6362-6373. 

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