Self-cleaning surfaces

For example, Asuri and his co-workers (Asuri et al., 2007) reported that the proteases attached to the surface of SWCNTs can create self-cleaning surfaces that resist protein adsorption. This kind of SWCNT-enzyme composite exhibited 30 times higher overall catalytic activity than control composites where the proteases were conjugated to a non-nanoscale graphite support. Importantly, the enzymes preserved more than 90% of their initial activity over 30% days in the liquid buffer, with only negligible amounts of enzymes leaching out. The result demonstrates that the nanocomposites of SWCNTs and polymers can act as hosts for enzymes and can prevent protein contamination on the surface of medical devices. We consider that SWCNTs may have the function as biocatalyst to improve the enzyme activity attached to the surface of CNTs. Our previous work also indirectly hints that CNTs could improve the bioactivity of enzymes such as Taq enzyme Cui et al. (2004). However, there are also adverse reports. CNTs can... 

Figure 1 Estimated number of scientific manuscripts on titanium dioxide photocatalysis per year, categorized according to water treatment (empty triangles), air treatment (filled diamonds), self-cleaning surfaces (empty circles).

The Lotus Effect simulates the properties of the lotus flower in nature, by microstructured hydrophobic protrusions which enable surfaces to clean themselves by water in motion. By making use of innovative technologies, the Lotus Effect can be used on many different products. For example, self-cleaning surfaces could be used for self-adhesive films, injection moulded parts or painted components in the construction industry, for facade elements or window frames, for traffic facilities such as road signs, and not to forget cars themselves. 

Design of self-cleaning surfaces for technical applications Lotus-Effect ... 

Spiropyran molecules have also been utilized as reverse wettable surfaces, whereby, a hydrophilic surface may be photomodulated to a hydrophobic surface and vice versa. Lygeraki et al. utilized the polar (mercocyanine, zwitterionic open-form) and nonpolar (spiropyran closed-form) properties of the spiropyran-merocyanine photo-chromic transformation to photomodulate surface wettability. 6-N02 BIPS (10 wt %) was added to a poly(methy 1 methacrylate) host matrix and patterned to produce reverse wettable surfaces. However, reversibility is limited to 6-8 irradiation cycles because of degradative photooxidation [22], Reverse wettable surfaces are commercially important as they may enhance drug delivery or function as a self-cleaning surface. 

The cements containing active photocatalytic titania nanoparticles have widespread applications to create environmentally clean surfaces. These applications include self-cleaning surfaces, anti-soiling, depollution of VOCs and NOx contaminants and antifungal/microbial activities [521-528]. The relevant photocatalytic processes may occur both at the air-solid interface and at the liquid-solid interface. 

Nanosheets, Nanofibers, NS-Ti02, Sol-gel process. Nanoclays, Doped-Ti02, Hydrothermal process. Photocatalysis, Electrocatalysis, Solar cell. Lithium batteries. Antibacterial surfaces. Self-cleaning surfaces, Photocatalytic cancer treatment, H2 production. Environmental remediation. Immobilized 7702. 

From an economic view, ETFE-fods are to be assessed positively. The production costs of fods are relatively low. Due to their self-cleaning surface properties, maintenance costs in the form of cleaning of the building envelopes are lower compared to glass. The energy costs for the stabilising pressures of pneumatic fod cushions are also relatively low due to the low pressures (ETFE-fod cushions constitute a low pressure system with pressures usually lower than 1000 Pa). 

Biomimetic textiles are under development and these include hydrophobic, self-cleaning surfaces analogous to the behaviour of leaf surfaces occurring in nature, such as the lotus plant, and flexible, translucent thermal insulated membranes analogous to the behaviour of the polar bear s fur (Stegmaier and Planck, 2007). 

Within the disciplines of architecture and engineering, biomimetics is playing a more and more important role in research into lightweight constructions and technical surfaces. In the development of self-cleaning surfaces, fagade colours like Lotosan have been established in the market of products for the building industry [8-10]. 

This type of species is important for photocatalysis because it provides a surface sink for photogenerated electrons. Additionally, this type of species is particularly important with respect to the wetting properties of Ti02, which is of importance to self-cleaning surfaces. 

The same fundamental phenomenon, that is, the great increase in wettability on UV illumination, can be used in two broad areas of applications, that is, self-cleaning surfaces and antifogging or antibeading surfaces. Both of these areas are treated briefly. 

Surface wettability is a significant factor in determining the physical and chemical properties of materials. Superhydrophobic surfaces have found application in a variety of settings, including self-cleaning surfaces, prevention of snow sticking, oxidation and heat conduction processes and others [1-3], Considering the... 

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