C hapter 10 nanomaterial product Forms and Functions
414
Obviously, unless direct washing is done, the cleaning process is
quite slow at best and does not work well. Products of this type
need UV light and are not suitable for interior applications. They
work best for small organic matter and when there is periodic
washing via rain or other means. They do not work well for really
large deposits of any kind (bird droppings remain problematic).
With thick organic deposits, however, normal cleaning is made
much easier.
Use of these kinds of self-cleaning surfaces also helps prevent streaking and generally reduces the need for harsh detergents in cleaning.
In many senses, this general kind of technology yields surfaces that
are perhaps better described as “easy to clean” than “self-cleaning,” even though some of the latter action surely occurs. These
“easy-to-clean” actions have consequences that go beyond visual
appearances. As noted in Chapter 11 on environmental impacts,
huge amounts of effort and energy go into cleaning large surfaces
in buildings and other forms of construction, and sometimes environmentally doubtful substances are used to aid in cleaning. Any
advances in reducing cleaning problems save not only human effort
and energy but could potentially help in reducing environmental
problems as well.
self-cleaning paints, textiles, and other materials
Many other material forms use self-cleaning technologies. Paints
that are relatively thick in comparison to the thin coatings on glass
are also touted as having self-cleaning properties and are based on
similar technical principles (see Figure 10.12). Titanium dioxide,
zinc oxide, and other kinds of nanoparticles are used in paints to
provide the photocatalytic action that loosens foreign particles to
be carried away by water runoff. Titanium dioxide has long been
used as a pigment in paints, but nanosized particles show greater
photocatalytic actions than do the normal pigment-sized particles
because of their greater relative surface area. The subsequent runoff
process can be enhanced using either hydrophilic effect.
These kinds of paints can be applied to many kinds of base materials, including metals. Applications that occur in a factory circumstance, as is common in metal panels used in vehicles, façade
elements in buildings, and other products, are invariably better than
simple hand painting or spraying. As with self-cleaning glasses, the
self-cleaning processes are slow and do not work equally effectively
with all kinds of surface deposits, but they do reduce the effort
needed to clean the surfaces when necessary. Self-cleaning paints
are being widely explored for use in automobile finishes. In all
414
Obviously, unless direct washing is done, the cleaning process is
quite slow at best and does not work well. Products of this type
need UV light and are not suitable for interior applications. They
work best for small organic matter and when there is periodic
washing via rain or other means. They do not work well for really
large deposits of any kind (bird droppings remain problematic).
With thick organic deposits, however, normal cleaning is made
much easier.
Use of these kinds of self-cleaning surfaces also helps prevent streaking and generally reduces the need for harsh detergents in cleaning.
In many senses, this general kind of technology yields surfaces that
are perhaps better described as “easy to clean” than “self-cleaning,” even though some of the latter action surely occurs. These
“easy-to-clean” actions have consequences that go beyond visual
appearances. As noted in Chapter 11 on environmental impacts,
huge amounts of effort and energy go into cleaning large surfaces
in buildings and other forms of construction, and sometimes environmentally doubtful substances are used to aid in cleaning. Any
advances in reducing cleaning problems save not only human effort
and energy but could potentially help in reducing environmental
problems as well.
self-cleaning paints, textiles, and other materials
Many other material forms use self-cleaning technologies. Paints
that are relatively thick in comparison to the thin coatings on glass
are also touted as having self-cleaning properties and are based on
similar technical principles (see Figure 10.12). Titanium dioxide,
zinc oxide, and other kinds of nanoparticles are used in paints to
provide the photocatalytic action that loosens foreign particles to
be carried away by water runoff. Titanium dioxide has long been
used as a pigment in paints, but nanosized particles show greater
photocatalytic actions than do the normal pigment-sized particles
because of their greater relative surface area. The subsequent runoff
process can be enhanced using either hydrophilic effect.
These kinds of paints can be applied to many kinds of base materials, including metals. Applications that occur in a factory circumstance, as is common in metal panels used in vehicles, façade
elements in buildings, and other products, are invariably better than
simple hand painting or spraying. As with self-cleaning glasses, the
self-cleaning processes are slow and do not work equally effectively
with all kinds of surface deposits, but they do reduce the effort
needed to clean the surfaces when necessary. Self-cleaning paints
are being widely explored for use in automobile finishes. In all